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COVID-19

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COVID-19

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COVID-19
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Vaccine Products Contraindications and Precautions
COVID-19 Vaccines for Children under 12 Years Vaccine Safety
COVID-19 Vaccines for Adolescents and Adults Storage and Handling
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This page was last updated on May 15, 2022. Guidance from CDC about COVID-19 vaccines may be updated frequently. For questions about guidance issued after this date, readers are referred directly to the Centers for Disease Control and Prevention (CDC) Use of COVID-19 Vaccines in the United States Interim Clinical Considerations: www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19-vaccines-us.html.

For a comprehensive collection of COVID-19 tools and resources, visit Immunize.org's Vaccines: COVID-19 main page: www.immunize.org/covid-19. For alerts about new Immunize.org or CDC COVID-19 resources, subscribe to our weekly newsletter, IZ Express.
Disease Issues
What is COVID-19?
COVID-19 is the name given to the disease caused by infection with the SARS-CoV-2 coronavirus. This virus was first detected as a cause of human illness in late 2019 in Wuhan, China, and triggered a global pandemic that began in 2020. The virus is thought to spread mainly from person to person through respiratory droplets produced when an infected person coughs, sneezes, or talks. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. Some people who are infected have no symptoms of illness, while the severity of symptomatic illness ranges from mild to life-threatening. Older adults and people of any age with underlying medical conditions are at higher risk for severe illness.
The incubation period after exposure ranges from 2–14 days, with an average of about 5 days. People with COVID-19 are generally considered infectious up to 48 hours before symptom onset through 10 days after onset, though people with severe illness may be infectious longer. Symptoms may include fever or chills, cough, shortness of breath or difficulty breathing, fatigue, muscle or body aches, headache, new loss of taste or smell, sore throat, congestion or runny nose, nausea or vomiting, and diarrhea.
Where can I find answers to more clinical questions about COVID-19 disease, diagnosis, treatment and care of patients?
The CDC has assembled clinical questions and answers at this site: www.cdc.gov/coronavirus/2019-ncov/hcp/faq.html.
Vaccine Recommendations Back to top
Where can I find current COVID-19 vaccine recommendations?
The CDC's Advisory Committee on Immunization Practices (ACIP) has published recommendations for all COVID-19 vaccines that have received Emergency Use Authorization (EUA) or licensure from the federal Food and Drug Administration (FDA). ACIP and the CDC update vaccination recommendations frequently. Changes in CDC recommendations may be issued without an ACIP meeting or vote. All ACIP COVID-19 vaccine recommendations that have been published by CDC in MMWR can be accessed here: www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/covid-19.html.
In addition to published ACIP recommendations for the use of these vaccines, CDC maintains a website with critical interim clinical considerations for vaccination of eligible recipients: www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19-vaccines-us.html. This site is updated within days of any change to CDC recommendations.
Has CDC developed a frequently asked question (FAQ) page for COVID-19 vaccines?
Yes. CDC has an FAQ page about COVID-19 vaccines specifically for healthcare providers: www.cdc.gov/vaccines/covid-19/hcp/faq.html. This page includes CDC answers related to vaccination programs, EUA, administration, storage and handling, and safety and efficacy.
Who is recommended to receive COVID-19 vaccines?
All people age 5 years and older in the United States are recommended to receive an age-appropriate COVID-19 vaccination. Details of recommendations for each product are available here: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#recommendations.
Who is eligible to receive a booster dose of a COVID-19 vaccine?
ACIP recommends that all people who have completed primary vaccination against COVID-19 and are age 12 years or older should receive one age-appropriate COVID-19 vaccine booster dose at the appropriate interval. The mRNA COVID-19 vaccines are feasible for use in most circumstances. However, offering the Janssen COVID-19 Vaccine under the limited terms of its current FDA emergency use authorization (www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/janssen-covid-19-vaccine) is preferable to not providing any COVID-19 vaccine.
People age 18 years or older who received the single dose of Janssen COVID-19 Vaccine (Johnson & Johnson) primary vaccination should receive a single COVID-19 booster dose (use an mRNA vaccine unless not feasible) at least 2 months (8 weeks) after the Janssen COVID-19 single dose primary vaccination. Among those who are moderately or severely immunocompromised and recommended to receive an additional mRNA vaccine dose 28 days after the dose of Janssen vaccine, the booster dose (dose 3) is due at least 2 months (8 weeks) after the additional mRNA primary dose.
People age 12 years or older who received a 2-dose mRNA vaccine primary series should receive a booster dose of an age-appropriate COVID-19 vaccine at least 5 months after completing the primary series (use an mRNA vaccine unless it is not feasible). Among those who are moderately or severely immunocompromised and recommended to receive a 3-dose primary mRNA vaccine series, a booster dose (dose 4) is recommended at least 3 months after dose 3.
A second booster dose of an age-appropriate mRNA vaccine may be considered for individuals who are moderately or severely immunocompromised and age 12 years or older, as well as for individuals who are not immunocompromised and are age 50 years or older. This optional second booster dose may be given at least 4 months following the first booster dose.
For details, please review the recommendations information available at CDC's web page, "Use of COVID-19 Vaccines in the United States Interim Clinical Considerations": www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#recommendations.
I know that the authorized and recommended use of Janssen COVID-19 is now limited to certain individuals. Who may receive the Janssen COVID-19 Vaccine?
The ACIP voted in December 2021 to prefer the use of mRNA vaccines for the prevention of COVID-19 because the Janssen vaccine is associated with very rare, but serious, side effects: thrombosis with thrombocytopenia (TTS) and Guillain-Barré Syndrome (GBS). Cases of TTS have occurred among male and female adults of all ages, with the highest rate among women age 30 to 49 (about 1 case per 100,000 doses). Approximately 15% of reported TTS cases have been fatal. See the section on vaccine safety for additional information. The mRNA vaccines have not been associated with these side effects.
In light of these facts and the widespread availability of mRNA vaccines, in May 2022, FDA limited its EUA for the Janssen COVID-19 Vaccine. The EUA now states that the Janssen vaccine is available to prevent COVID-19 in individuals 18 years of age and older for whom other FDA-authorized or approved COVID-19 vaccines are not accessible or are not clinically appropriate, and individuals 18 years of age and older who elect to receive it because they would otherwise not receive a COVID-19 vaccine. For these individuals, the Janssen COVID-19 vaccine is authorized as:
a single primary vaccination dose
a single booster dose at least two months after completing primary vaccination with the vaccine
  a single booster dose following completion of primary vaccination with a different available COVID-19 vaccine. The dosing interval for the booster dose is the same as that authorized for a booster dose of the vaccine used for primary vaccination.
All people who elect to receive a Janssen COVID-19 vaccine booster should be informed about the risk and symptoms of TTS that could occur after vaccination (typically within 2 weeks after receipt) and the need to seek immediate medical care should such symptoms develop at any time.
Should people who have had COVID-19 illness be vaccinated?
Yes. Vaccination should be offered to individuals regardless of history of prior SARS-CoV-2 infection. People who are unvaccinated have a higher risk of reinfection than those who are fully vaccinated following natural infection. CDC has summarized the available data on vaccine-induced immunity and disease-induced immunity here: www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/vaccine-induced-immunity.html.
Viral testing to assess for current SARS-CoV-2 infection or serologic testing to assess for prior infection for the purposes of vaccine decision-making is not recommended. However, as with all vaccines, vaccination should be deferred until after recovery from moderate to severe illness. In addition, to minimize the risk of exposing others to SARS-CoV-2 virus, vaccination of a person diagnosed with COVID-19 generally should be deferred until criteria have been met for individuals with COVID-19 illness to discontinue isolation.
What is the difference between an "additional primary dose" of COVID-19 vaccine recommended for an immunocompromised person and a "booster dose"?
CDC defines an "additional primary dose" as a subsequent dose of vaccine administered to people who are less likely to develop a protective immune response after initial vaccination. People age 5 years or older who are moderately or severely immunocompromised should receive an additional primary dose of mRNA vaccine 4 weeks after the routinely recommended primary series.
CDC defines a "booster dose" as a subsequent dose of vaccine administered to enhance or restore protection which might have declined over time after primary series vaccination.
A "homologous booster dose" simply means that the same vaccine product used for the booster dose was administered for the primary series.
A "heterologous booster dose," sometimes referred to as a mix-and-match booster, is a vaccine product used for the booster dose that differs from the product administered for the primary series.
How does CDC define being "up to date" on COVID-19 vaccination?
CDC has used the term "fully vaccinated" to refer to people who have completed a primary COVID-19 vaccine series. CDC currently uses the term "up to date" (UTD) to refer to a person who has received all recommended doses in their primary vaccine series, and a single booster dose, when eligible. A second booster dose is not necessary to be considered up to date at this time.
Vaccine Products Back to top
What is an Emergency Use Authorization (EUA)?
Under section 564 of the Federal Food, Drug, and Cosmetic Act (FD&C Act), the FDA Commissioner may allow unapproved medical products or unapproved uses of approved medical products to be used in an emergency to diagnose, treat, or prevent serious or life-threatening diseases or conditions caused by chemical, biological, radiological or nuclear threat agents when there are no adequate, approved, and available alternatives. Vaccines that receive an EUA may later be fully licensed by the FDA.
Which vaccines are currently licensed by the FDA?
On August 23, 2021, FDA approved the 2-dose primary series of the adolescent/adult formulation of Pfizer-BioNTech COVID-19 Vaccine for individuals age 16 years and older. The brand name of this product is Comirnaty.
On January 31, 2022, FDA approved the 2-dose primary series of Moderna COVID-19 Vaccine for individuals age 18 years and older. The brand name of this product is Spikevax.
What does FDA's approval of the biologics licensure application (BLA) for Comirnaty, the Pfizer-BioNTech COVID-19 Vaccine, mean for my clinic?
On August 23, 2021, FDA approved the BLA for the adolescent/adult formulation of Pfizer-BioNTech COVID-19 Vaccine for individuals age 16 years and older; its trade name is Comirnaty. In late 2021, FDA approved a manufacturing change for Comirnaty to use a different buffer to improve the stability of the vaccine; Comirnaty made with this buffer does not require dilution. It is packaged with a gray cap and gray trim around its label. As the existing supplies of the original purple cap (dilute before use) Comirnaty are replaced by the newer gray cap (do not dilute) formulation through 2022, both formulations will be available. They are considered the same vaccine; however, vaccinators must be careful to ensure that they are stored and handled correctly because their storage and handling requirements are different.
Comirnaty remains authorized for emergency use for children age 12 through 15 years, for administration of an additional primary series dose in immunocompromised people ages 12 and older, and for administration as a booster dose to all people ages 12 and older. CDC has issued emergency use instructions (EUI) for the use of this vaccine in people age 12 or older whose primary series included a COVID-19 vaccine not authorized or approved by the FDA, given either as part of a clinical trial or as partial or complete routine vaccination in another country. The EUI also addresses revaccination of people who have received hematopoietic cell transplant (HCT) therapy or CAR-T-cell therapy. EUI resources are available here: www.cdc.gov/vaccines/covid-19/eui/index.html.
For simplicity, the Ask the Experts COVID-19 section refers to Comirnaty as Pfizer-BioNTech COVID-19 Vaccine, referring, when necessary, to its two formulations as the purple cap (dilute before use) or gray cap (do not dilute) formulations to distinguish them from the orange cap (dilute before use) formulation specifically for children ages 5 through 11 years.
The FDA Fact Sheet reflects the trade name and combines information for individuals receiving the adolescent/adult formulation in accordance with its licensed indication with information for those receiving the product under the terms of its emergency use authorization (EUA).
All clinics providing the adolescent/adult Pfizer-BioNTech COVID-19 Vaccine for a recipient age 12 years or older should use the most current EUA Fact Sheet that corresponds with the correct (purple or gray cap) formulation. The current EUA Fact Sheets for healthcare providers and for recipients and caregivers in English and additional languages are available from FDA at this web page: www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/Comirnaty-and-pfizer-biontech-covid-19-vaccine.
What are the differences in the purple cap (dilute before use), gray cap (do not dilute), and orange cap (dilute before use) formulations of Pfizer-BioNTech COVID-19 Vaccine?
The purple cap (dilute before use) formulation of Pfizer-BioNTech COVID-19 Vaccine for age 12 years and older has a purple plastic vial cap over the vial stopper and purple trim on the vial label, and the EUA Fact Sheets for this formulation have a corresponding purple box around the title.
The gray cap (do not dilute) formulation of Pfizer-BioNTech COVID-19 Vaccine for age 12 years and older has a gray plastic vial cap over the vial stopper and gray trim on the vial label, and the EUA Fact Sheets for this formulation have a corresponding gray box around the title.
The purple cap and gray cap are the same vaccine (with each dose containing 30 mcg of mRNA), formulated with different buffers. As a result, they have very different storage and handling requirements. In late 2021, FDA approved a manufacturing change for Comirnaty (adolescent/adult Pfizer-BioNTech COVID-19 Vaccine) to include a formulation that uses a different buffer. The new formulation (gray cap) contains Tris buffer, a commonly used buffer in other FDA-approved vaccines and biologics. This new formulation is more stable at refrigerated temperatures for longer periods of time. The gray cap formulation does not need to be diluted before use.
The orange cap (dilute before use) formulation for ages 5 through 11 years has an orange plastic vial cap over the vial stopper and orange trim on the label, and the EUA Fact Sheets for this formulation have a corresponding orange box around the title.
The orange cap (dilute before use) formulation of Pfizer-BioNTech COVID-19 Vaccine given to children age 5 through 11 years contains the same mRNA encoding the same antigen as the purple cap and gray cap formulations, but it comes in a different package, in a different vial, with a different concentration, a different dilution volume, a different dose, and has different storage requirements. Vaccinators should practice extreme care to ensure that they follow the correct storage, preparation, and administration directions for each product to avoid vaccine handling or administration errors.
Pfizer-BioNTech has produced a table outlining the critical differences in these three formulations: www.cvdvaccine-us.com/images/pdf/Vaccine-Formulation-Presentation-Guide.pdf.
All EUA Fact Sheets for licensed and authorized Pfizer-BioNTech formulations are posted by the FDA on this website: www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/comirnaty-and-pfizer-biontech-covid-19-vaccine.
When will we have a VIS for the vaccines that have an EUA? What information am I supposed to give patients in writing?
For each COVID-19 vaccine authorized under an Emergency Use Authorization (EUA), the Food and Drug Administration (FDA) requires that vaccine recipients or their caregivers are provided with certain vaccine-specific EUA information to help make an informed decision about vaccination. This is accomplished by providing an EUA Fact Sheet for Recipients and Caregivers. The Fact Sheet is similar in purpose and content to vaccine information statements (VISs) for licensed vaccines but differs in that the EUA Fact Sheet is specific to each authorized COVID-19 vaccine, is developed by the manufacturer of the vaccine, and is authorized by the FDA. There is a separate EUA Fact Sheet for each formulation of a vaccine. For example, there are different Fact Sheets for each of the three Pfizer-BioNTech COVID-19 Vaccine formulations (orange cap, gray cap, and purple cap).
CDC has issued Emergency Use Instructions (EUI) for the use of the FDA-licensed formulations of Pfizer-BioNTech COVID-19 Vaccine (Comirnaty), or Moderna COVID-19 Vaccine (Spikevax) for certain people vaccinated with vaccines not authorized or approved by the FDA, whether given outside the United States or as part of a clinical trial. The EUI also addresses revaccination of people who have received hematopoietic cell transplant (HCT) or CAR-T-cell therapy. These instructions may differ from the FDA-approved labeling (the package insert). People vaccinated in accordance with these emergency use instructions should be given an EUI Fact Sheet at the time of vaccination. Information about CDC EUI and links to these fact sheets for providers and recipients or caregivers are available here: www.cdc.gov/vaccines/covid-19/eui/index.html.
There is no VIS for COVID-19 vaccines authorized under an EUA. FDA has issued revised fact sheets for Comirnaty and Spikevax that cover both their limited licensed indications as a primary series for people age 16 and older (Comirnaty) or age 18 and older (Spikevax) and their broader emergency use authorizations. Once a COVID-19 VIS is issued, the VIS and all available translations will be posted here: https://immunize.org/vis/.
The combined Fact Sheet for Recipients and Caregivers about Comirnaty and Pfizer-BioNTech COVID-19 Vaccine (ages 12 years and older, purple cap, dilute before use) is available here: www.fda.gov/media/153716/download.
The combined Fact Sheet for Recipients and Caregivers about Comirnaty and Pfizer-BioNTech COVID-19 Vaccine (ages 12 years and older, gray cap, do not dilute) is available here: www.fda.gov/media/153715/download.
The orange cap Pfizer COVID-19 Vaccine EUA Fact Sheet for Recipients and Caregivers (ages 5 through 11 years) is available here: www.fda.gov/media/153717/download.
The combined Fact Sheet for Recipients and Caregivers about Spikevax and Moderna COVID-19 Vaccine is available here: www.fda.gov/media/144638/download.
The Janssen COVID-19 Vaccine EUA Fact Sheet for Recipients and Caregivers is available here: www.fda.gov/media/146305/download.
What is the difference between the presentation of "booster dose only" Moderna COVID-19 Vaccine introduced in March 2022 and the other presentation?
A primary series dose of Moderna COVID-19 vaccine for individuals age 18 years and older is 100 micrograms (mcg) and a booster dose is 50 mcg. The multidose vials of FDA-licensed Spikevax and one multidose vial presentation of the authorized Moderna COVID-19 Vaccine (with a red cap) are interchangeable and may be used to deliver either a 100 mcg primary series dose in 0.5 mL volume or a 50 mcg booster dose in 0.25 mL volume.
In March 2022, the FDA authorized use of a second presentation of Moderna COVID-19 Vaccine only for booster doses. This presentation is in a multidose vial with a dark blue cap and purple outline on the vial label. Each dose contains 50 micrograms in a volume of 0.5 mL; it is not authorized for primary series (100 mcg) doses.
Vaccinators who stock both presentations should check three times to confirm that they are administering the proper product with the proper dose and dose volume for each patient.
 
What are mRNA vaccines?
Both the Pfizer-BioNTech COVID-19 Vaccine and the Moderna COVID-19 (mRNA-1273) Vaccine are lipid nanoparticle-formulated, nucleoside-modified mRNA vaccines encoding the prefusion spike glycoprotein of SARS-CoV-2, the virus that causes coronavirus disease 2019. Both mRNA vaccines have been associated with a rare occurrence of myocarditis and/or pericarditis; cases have occurred predominantly among males ages 12 through 39: see the vaccine safety section for additional information. Visit this CDC website for more details about how mRNA vaccines work: www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/mrna.html.
How well did the mRNA COVID-19 vaccines work in the clinical trials?
The FDA EUA was issued based upon the short-term effectiveness of these vaccines at preventing symptomatic illness with COVID-19. The Pfizer-BioNTech vaccine (Comirnaty) was licensed by FDA with a reported vaccine efficacy of 91.1% against symptomatic disease among recipients age 16 years or older up to 6 months after dose 2. Both Moderna and Pfizer-BioNTech vaccines maintain approximately 90% protection against severe disease for at least 6 months after vaccination. Early observational studies of short-term effectiveness in a variety of populations were consistent with the clinical trial results. Vaccine effectiveness wanes over time and can be improved by the administration of booster doses as recommended by CDC. Vaccine effectiveness may be different for new variants of COVID-19.
Please describe the Janssen COVID-19 Vaccine (Johnson & Johnson).
The Janssen vaccine is a recombinant, replication-incompetent (unable to reproduce) adenovirus serotype 26 (Ad26) vector vaccine, encoding the stabilized prefusion spike glycoprotein of SARS-CoV-2. On February 27, 2021, the FDA first issued an Emergency Use Authorization (EUA) for the Janssen COVID-19 (Ad.26.COV2.S) Vaccine (Johnson & Johnson). Due to the extremely rare risk of the serious complications of thrombosis with thrombocytopenia syndrome (TTS) or Guillain-Barre syndrome (GBS) following vaccination with this product, the Janssen COVID-19 Vaccine is currently authorized for use in individuals 18 years of age and older for whom other FDA-authorized or approved COVID-19 vaccines are not accessible or clinically appropriate, and for individuals 18 years of age and older who elect to receive the Janssen COVID-19 Vaccine because they would otherwise not receive a COVID-19 vaccine.
Primary vaccination of people who are not moderately or severely immunocompromised consists of a single dose of Janssen vaccine administered intramuscularly. A booster dose of any authorized or licensed COVID-19 vaccine is recommended at least 2 months (8 weeks) following this single dose. A second booster dose of an mRNA vaccine administered at least 4 months after the first booster dose may be considered for recipients age 50 years or older.
People age 18 years or older with moderate to severe immunocompromise who receive a primary dose of Janssen vaccine should receive an additional primary dose of an mRNA vaccine at least 28 days after the Janssen vaccine. A booster dose of any authorized or licensed COVID-19 vaccine (preferably mRNA) is recommended at least 2 months after the additional primary dose, for a total of 3 doses. A second booster dose of an mRNA vaccine may be considered 4 months after the first booster dose for all of these moderately or severely immunocompromised recipients.
How well did the Janssen COVID-19 Vaccine work in the clinical trials?
A large phase 3 trial was initiated in September 2020 and enrolled more than 43,000 individuals in multiple countries, including the United States, Brazil, and South Africa. Interim results demonstrated a 66% reduction in the risk of symptomatic COVID-19 beginning at least 14 days following vaccination; efficacy against severe disease was higher. The risk of hospitalization 14 days or more after vaccination was reduced by 93% compared to placebo recipients; no hospitalizations occurred among vaccine recipients 28 days or more after vaccination. No deaths related to COVID-19 infection occurred among vaccine recipients, while seven occurred among placebo recipients.
In the months following EUA, vaccine effectiveness against severe disease and hospitalization remained high against known variants, including the Delta variant, even as protection against milder illness appeared reduced. Receipt of a booster dose at least 2 months after the primary dose substantially increases neutralizing antibodies to levels consistent with a high degree of protection against symptomatic infection. Due to the occurrence of very rare but serious side effects, mRNA vaccines (which are not associated with these side effects) are preferred over Janssen vaccine for primary and booster vaccination of eligible recipients in the United States. Vaccine effectiveness may be different for different variants of COVID-19.
How well do COVID-19 vaccines work to prevent asymptomatic infection with SARS-CoV-2? Based on that, what can people do when they are up to date on their COVID-19 vaccinations?
Some evidence suggests that people who are up to date (UTD) with COVID-19 vaccination are less likely than the unvaccinated to have asymptomatic infection or transmit SARS-CoV-2 to others; however, the degree of protection varies depending on the variant of the virus in circulation and declines over time. CDC guidelines for UTD individuals are updated as new data become available: www.cdc.gov/coronavirus/2019-ncov/vaccines/fully-vaccinated-guidance.html.
 
Where can I obtain detailed information about the COVID-19 vaccines?
CDC has developed a "one-stop" product-specific webpage for each COVID-19 vaccine with all of the important details that immunization providers need to know.
Pfizer-BioNTech COVID-19 Vaccine (all formulations): www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/index.html.
Moderna COVID-19 Vaccine: www.cdc.gov/vaccines/covid-19/info-by-product/moderna/index.html.
  Janssen COVID-19 Vaccine: www.cdc.gov/vaccines/covid-19/info-by-product/janssen/index.html.
In addition to CDC, each company has a detailed EUA Fact Sheet for Providers.
Pfizer-BioNTech COVID-19 Vaccine (for ages 12 years and older, purple cap): www.fda.gov/media/153713/download
Pfizer-BioNTech COVID-19 Vaccine (for ages 12 years and older, gray cap): www.fda.gov/media/153715/download
  Pfizer-BioNTech COVID-19 Vaccine (for ages 5 through 11 years, orange cap): www.fda.gov/media/153714/download
  Moderna COVID-19 Vaccine (primary series and booster dose presentation, red cap, ages 18 years and older): https://eua.modernatx.com/covid19vaccine-eua/eua-fact-sheet-providers.pdf
  Moderna COVID-19 Vaccine (booster dose only presentation, dark blue cap, ages 18 years and older): https://eua.modernatx.com/covid19vaccine-eua/eua-fact-sheet-booster-providers.pdf
  Janssen COVID-19 Vaccine: www.fda.gov/media/146304/download
COVID-19 Vaccines for Children under 12 Years Back to top
What are the recommendations for COVID-19 vaccination of children younger than 12 years?
On November 2, 2021, ACIP voted to recommend COVID-19 vaccination of all children age 5 through 11 years with two 10 mcg (0.2 mL) doses of the orange cap (dilute before use) formulation of Pfizer-BioNTech COVID-19 Vaccine, administered 21 days apart.
As of January 4, 2022, children in this age group with moderate or severe immunocompromise also are recommended to receive an additional primary dose at least 28 days after dose 2. As of May 15, 2022, CDC does not recommend a booster dose following the completion of the primary series for any children in this age group at this time.
CDC has summarized the current recommended immunization schedule for all age groups in this print-ready document: www.cdc.gov/vaccines/covid-19/downloads/COVID-19-immunization-schedule-ages-5yrs-older.pdf.
Our clinic does not stock the orange cap formulation of Pfizer-BioNTech COVID-19 Vaccine for children age 5 through 11 years. Could we draw up a 10 microgram (mcg) dose out of the purple cap adolescent/adult formulation to vaccinate these children?
No. Children 5 through 11 years should only be vaccinated with a 10 mcg dose (0.2 mL) of the orange cap (dilute before use) Pfizer-BioNTech formulation specifically authorized for ages 5 through 11 years, except as permitted by the FDA when a child is within 21 days of their 12th birthday, as described in the next question.
A dose of the purple cap (dilute before use) or gray cap (do not dilute) formulation for adolescents and adults delivers 30 mcg in a 0.3 mL volume. Ten mcg (the dose for a child 5 through 11 years) would be just 0.1 mL, a volume too small to reliably deliver the correct amount intramuscularly. It is never acceptable to alter the dilution volume or to dilute a formulation that should not be diluted in order to create a larger dose volume.
My patient turns 12 years old later this month. Should they get the orange cap Pfizer-BioNTech formulation for children now or wait to get the purple or gray cap Pfizer-BioNTech vaccine formulation for adolescents and adults?
Do not wait. Ideally, children should receive the vaccine dosage and formulation authorized specifically for their age on the day of vaccination with each dose. If a child turns 12 years old between their first and second dose, they should receive the age-appropriate 30 mcg purple cap (dilute before use) or gray cap (do not dilute) Pfizer-BioNTech COVID-19 Vaccine formulation for their second dose to complete their series. However, the FDA authorization provides flexibility in this circumstance. Children who will turn age 12 years between their first and second dose in the primary regimen may receive two orange cap doses, two purple or gray cap doses, or any combination of orange cap, purple cap, or gray cap: in any of these circumstances the child is considered fully vaccinated. This is not considered an error and VAERS reporting is not indicated.
What do we know about the orange cap Pfizer-BioNTech COVID-19 Vaccine effectiveness and side effects in children ages 5 through 11 years?
Preliminary clinical trial results (initial enrollment of 2,268 children) showed that two 10-microgram (mcg) doses of orange cap (dilute before use) Pfizer-BioNTech COVID-19 Vaccine formulation for age 5 through 11 years, administered 21 days apart, reduced the risk of symptomatic COVID-19 illness by 90.9 percent for at least two months. The immune response to this dose in this age group was at least as strong as the immune response to two 30 mcg doses of the purple cap Pfizer-BioNTech COVID-19 Vaccine formulation among recipients age 16 through 25 years.
During the 7 days following vaccination, almost 9 in 10 children reported a local reaction, primarily pain at the injection site, and 2 of 3 reported a systemic reaction (most commonly fatigue or headache). The vast majority of reactions were mild or moderate and resolved within 1?2 days; reactions were milder than those reported by young adult recipients of the purple cap formulation. Systemic reactions were more likely to be reported following dose 2. No serious adverse events related to vaccination were observed in the clinical trial.
COVID-19 Vaccines for Adolescents and Adults Back to top
What ages are authorized to receive the available COVID-19 vaccines?
The orange cap (dilute before use) Pfizer-BioNTech COVID-19 Vaccine is authorized for emergency use in people ages 5 through 11 years. The purple cap (dilute before use) and gray cap (do not dilute) formulations of the Pfizer-BioNTech COVID-19 Vaccine are authorized for emergency use in people age 12 years and older; these formulations are licensed (with the brand name Comirnaty) for ages 16 years and older.
Moderna (Spikevax) is licensed and authorized for use in people age 18 and older. Janssen COVID-19 vaccines are authorized for emergency use in certain people age 18 years and older for whom vaccination with an mRNA vaccine is not feasible.
FDA authorization of additional vaccine products or authorization of current products for expanded age groups could occur if sufficient data are generated and submitted in an application to FDA.
What is the recommended interval between dose 1 and dose 2 of mRNA vaccines for people age 12 years and older and why did it change?
On February 22, 2022, CDC adjusted its recommendations to provide the option of an 8-week interval between doses 1 and 2 of mRNA vaccines for certain people ages 12 through 64 years. Large observational studies in other countries have provided evidence that an 8-week interval may result in higher antibody levels and a reduced risk of vaccine-associated myocarditis, which is most likely to occur after dose 2. For this reason, an 8-week interval may be optimal for some people ages 12 years through 64 years, especially males ages 12 through 39 years who are at the greatest risk of myocarditis after dose 2.
Shorter intervals (3 weeks for Pfizer-BioNTech; 4 weeks for Moderna) protect the recipient more quickly. Therefore, a shorter interval remains the recommended interval for the following groups:
All people who are moderately to severely immunocompromised
All children under 12 years (where the risk of vaccine-associated myocarditis is much lower)
  All adults age 65 years and older
  Others who need rapid protection due to increased concern about community transmission or risk of severe disease
What is the difference between the gray cap and purple cap formulations of Pfizer-BioNTech COVID-19 Vaccine?
The purple cap (dilute before use) and gray cap (do not dilute) are the same vaccine (with each dose containing 30 mcg of mRNA), formulated with different buffers. As a result, they have the same schedule and dosage, but very different storage and handling requirements. In late 2021, FDA approved a manufacturing change for Comirnaty (adolescent/adult Pfizer-BioNTech COVID-19 Vaccine) to include a formulation that uses a different buffer. The new formulation (gray cap) contains Tris buffer, a commonly used buffer in other FDA-approved vaccines and biologics. This new formulation is more stable at refrigerated temperatures for longer periods of time. The gray cap (do not dilute) Pfizer-BioNTech COVID-19 Vaccine is used on the same schedule and for the same ages as the purple cap (dilute before use) vaccine (ages 12 years and older). The gray cap may be stored in an ultra-low temperature (ULT) freezer for up to 12 months and in the refrigerator up to 10 weeks. It should never be stored in an ordinary freezer, nor should it be refrozen after thawing.
Distribution of the purple cap (dilute before use) formulation within the United States ended on December 23, 2021. This product may be available for use until all supplies are used or expire by sometime during the second half of 2022. It may be stored in a ULT freezer for up to 12 months, in a standard freezer for up to 2 weeks, and in a refrigerator for up to one month (31 days). It should never be refrozen after thawing.
For a table showing the differences among the 3 Pfizer-BioNTech COVID-19 Vaccine formulations, refer to this table produced by Pfizer-BioNTech: www.cvdvaccine-us.com/images/pdf/Vaccine-Formulation-Presentation-Guide.pdf.
What do we know about the Pfizer-BioNTech COVID-19 Vaccine effectiveness and side effects in children and young teens in the 12- to 15-year-old age group?
Clinical trial results demonstrated that the immune response of young adolescents in this age group to two 30 mcg doses separated by 21 days was similar to that observed in people age 16–25 years. No symptomatic cases of COVID-19 were detected among fully vaccinated people age 12–15 years. Among vaccine recipients age 12–15 years, side effects during the 7 days after vaccination were commonly reported (90.9% of vaccine recipients reported a local reaction and 90.7% reported a systemic reaction). Most reactions were mild to moderate. Pain at the injection site was the most common local reaction. One in 10 reported a side effect that interfered with daily activities. Side effects usually resolved after 1–2 days. Systemic side effects (e.g., fever, fatigue, headache, muscle pain) were more commonly reported after the second dose than after the first dose. No specific safety concerns were identified among adolescent vaccine recipients.
Special Populations Back to top
Are COVID-19 vaccines safe during pregnancy?
A growing body of evidence on COVID-19 vaccination during pregnancy has not indicated any safety or effectiveness concerns for vaccination at any stage of pregnancy; the benefits of vaccination clearly outweigh any known or potential risks of COVID-19 vaccination during pregnancy. The currently authorized or licensed COVID-19 vaccines are non-replicating vaccines and cannot cause infection in either the mother or the fetus. No evidence exists of risk to the fetus from vaccinating pregnant people with non-replicating vaccines in general. Just like the general population, mRNA vaccines are preferred during pregnancy; Janssen vaccine may be considered when mRNA vaccination is not feasible.
No safety concerns were found in animal developmental and reproductive toxicity studies of animals that received Pfizer-BioNTech, Moderna, or Janssen vaccines. Reassuring early safety data on mRNA COVID-19 vaccines administered to people during pregnancy have been published by CDC. Data from the Vaccine Adverse Events Reporting System (VAERS), the v-safe surveillance system, and the v-safe pregnancy registry have not signaled any safety concerns for pregnant people who were vaccinated or their infants. The vaccine manufacturers are following the pregnancy outcomes of people in the clinical trials who became pregnant. Additional studies in pregnant people are ongoing in order to fully evaluate pregnancy and birth outcomes.
Pregnant individuals should be vaccinated and are encouraged to enroll in CDC's voluntary COVID-19 vaccine safety surveillance system, v-safe. The v-safe pregnancy registry follows outcomes among pregnant people who are vaccinated.
Can COVID-19 vaccination lead to fertility problems?
There is currently no evidence that any of the COVID-19 vaccines affect current or future fertility. In fact, there is currently no evidence that any vaccines cause fertility problems. Many individuals have become pregnant after receiving COVID-19 vaccine; ongoing long-term studies of pregnancy outcomes following vaccination are underway.
Are COVID-19 vaccines recommended during pregnancy?
Yes. COVID-19 vaccination is recommended for all people who are pregnant, lactating, trying to get pregnant now, or planning for future pregnancy. Pregnant people are at increased risk of severe complications and death from COVID-19 compared to non-pregnant people of the same age. Those who contract COVID-19 during pregnancy also have almost twice the risk of stillbirth compared to those who do not contract COVID-19 during pregnancy. Recent studies have shown that antibodies produced after COVID-19 vaccination during pregnancy are transferred to the newborn, and COVID-19 vaccination of people who are pregnant reduces the risk of COVID-19 hospitalization in infants younger than 6 months. Pregnant people may receive a booster dose during pregnancy, if eligible.
In all populations, mRNA vaccines are preferred. Janssen vaccine may be considered if use of mRNA vaccine is not feasible. However, Janssen vaccine recipients should be aware of the rare risk of blood clots with low platelet counts (thrombosis with thrombocytopenia syndrome [TTS]) after receipt of the Janssen vaccine.
CDC, the American College of Obstetricians and Gynecologists (ACOG), and the Society for Maternal-Fetal Medicine (SMFM) all recommend vaccination of pregnant people at any stage of pregnancy.
For more details about COVID-19 vaccination during pregnancy, visit CDC's webpage, "COVID-19 Vaccines while Pregnant or Breastfeeding": www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/pregnancy.html.
Are COVID-19 vaccines recommended if the recipient is breastfeeding?
Yes. COVID-19 vaccination is recommended for people who are lactating. As with the general population, mRNA vaccines are preferred over Janssen vaccine.
There are limited data on the safety of currently available COVID-19 vaccines on the breastfed infant or milk production/excretion. However, the currently available COVID-19 mRNA and non-replicating viral vector vaccines cannot cause infection in either the lactating person or the infant. More data are needed to determine if COVID-19 antibodies present in breastmilk convey protection against SARS-CoV-2 infection for infants.
Why is an additional primary dose of mRNA vaccine recommended for some immunocompromised people?
Moderately or severely immunocompromised people age 5 years or older (Pfizer-BioNTech recipients) or 18 years or older (Moderna or Janssen recipients) should receive an additional primary dose of mRNA COVID-19 vaccine at least 28 days after completion of the initial 2-dose series or after a single primary dose of Janssen vaccine. Recipients of mRNA vaccine should receive the same brand of mRNA vaccine as the first two doses in the primary series. Janssen vaccine recipients may receive a dose of either mRNA vaccine. Side effects experienced after an additional primary dose are similar to the side effects of prior doses.
Although the benefit of the additional primary dose of mRNA vaccine for a moderately or severely immunocompromised person is not precisely known, evidence shows it is safe and can provide better protection than the standard primary series.
Immunocompromised people who receive an additional primary dose 28 days or more after dose 2 should be counseled that they may still have a reduced immune response to COVID-19 vaccination. They should be advised to continue other recommended infection prevention measures, such as wearing a face mask and avoiding crowds, to limit their risk of exposure to the SARS-CoV-2 virus.
Immunocompromised people age 12 or older who receive an additional mRNA primary series dose should receive a booster dose (a fourth dose) at least 3 months after their additional (third) primary dose. They may also receive a second booster (dose 5) at least 4 months after their first booster dose. Among age-eligible recipients, mRNA vaccines are preferred for the first booster (Janssen vaccine may be considered if mRNA vaccination is not feasible); only mRNA vaccines are authorized to be used as the second booster. Moderna vaccine recipients should receive the full 100 mcg dose when Moderna vaccine is used as an additional (third) primary dose and should receive the 50 mcg dose when Moderna vaccine is used for a booster dose.
Immunocompromised people age 18 or older who receive an additional mRNA primary dose following a primary dose of Janssen vaccine should receive a booster dose at least 2 months after the additional primary dose, for a total of three doses. They may receive a second booster 4 months after the first booster. Only mRNA vaccines are authorized for the additional primary or second booster doses; they also are preferred for the first booster dose.
Exactly which immunocompromised groups are recommended to receive an additional primary dose of mRNA vaccine?
The age groups eligible are people age 5 years or older (Pfizer-BioNTech) and people age 18 years or older (Moderna or Janssen).
The conditions and treatments that may result in moderate or severe immunocompromise in these eligible age groups include but are not limited to:
Active treatment for solid tumor and hematologic malignancies
  Receipt of solid-organ transplant and taking immunosuppressive therapy
  Receipt of CAR-T-cell or hematopoietic stem cell transplant (within 2 years of transplantation or taking immunosuppression therapy)
  Moderate or severe primary immunodeficiency (such as DiGeorge syndrome or Wiskott-Aldrich syndrome)
  Advanced or untreated HIV infection
  Active treatment with high-dose corticosteroids (in other words, 20 mg or more of prednisone or equivalent per day), alkylating agents, antimetabolites, transplant-related immunosuppressive drugs, cancer chemotherapeutic agents classified as severely immunosuppressive, tumor-necrosis factor (TNF) blockers, and other biologic agents that are immunosuppressive or immunomodulatory
Additional factors to consider in assessing the general level of immune competence in a patient include disease severity, duration, clinical stability, complications, comorbidities, and any potentially immune-suppressing treatment. A patient's clinical care team is in the best position to evaluate the degree of immunocompromise and timing of vaccination.
For additional information, please review CDC's interim clinical considerations for this population: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#immunocompromised.
I have an oncology patient who was up to date on COVID-19 vaccination but is now in need of hematopoietic cell transplant (HCT). Will she require revaccination after HCT?
Yes. According to CDC's interim clinical considerations for the use of COVID-19 vaccines, recipients of HCT or CAR-T-cell therapy who received one or more doses of COVID-19 vaccine prior to or during treatment should be revaccinated (i.e., complete primary vaccination and any recommended booster doses) for any doses received before or during treatment. Any revaccination doses should be given with an mRNA vaccine and should start at least 3 months (12 weeks) after transplant or CAR-T-cell therapy. The patient's clinical team is best positioned to determine the degree of immune compromise, need for revaccination, and appropriate timing of revaccination.
My patient receives periodic infusions of rituximab for immunosuppressive treatment of an immune system disorder. Should we try to coordinate the timing of his COVID-19 vaccinations around his infusion schedule?
According to CDC's interim clinical considerations for the use of COVID-19 vaccines, whenever possible, COVID-19 vaccines should be administered at least 2 weeks before initiation or resumption of immunosuppressive therapies. Timing of COVID-19 vaccination should take into consideration current or planned immunosuppressive therapies and optimization of both the patient's medical condition and response to vaccine.
Should I conduct serologic testing or cellular immune testing before or after offering an additional primary dose of mRNA vaccine to an immunocompromised patient?
No. Serologic testing or cellular immune testing before or after an additional primary dose (outside the context of research studies) is not recommended.
Does it matter which brand of mRNA vaccine I give to an immunocompromised person who is recommended to receive an additional primary dose?
CDC recommends that the additional primary dose be given at least 28 days after dose 2 of an mRNA vaccine or after the single primary dose of Janssen vaccine. If mRNA vaccine is used for the primary series, the 3rd dose should be the same brand as the first two doses of the primary series. However, if the same brand is unavailable, you may administer the other mRNA vaccine, if the other vaccine is authorized for the recipient's age. If using Moderna, a full 100 mcg (0.5 mL) dose should be administered as the additional primary dose. Either mRNA vaccine may be used as the additional primary dose for a recipient of a primary dose of Janssen vaccine.
My patient, age 30, has moderate immunocompromise and received an additional primary dose as recommended. Is a booster dose also recommended?
Yes. Immunocompromised people who receive a 3-dose primary series of mRNA vaccine and are age 12 years or older also should receive a booster dose at least 3 months after receiving the additional primary (3rd) dose, for a total of 4 doses. They may subsequently receive a second booster of mRNA vaccine (5th dose) 4 months after their first booster dose.
Immunocompromised people who receive a Janssen primary dose followed by an mRNA vaccine additional primary dose should receive a booster dose at least 2 months after receiving the additional primary dose, for a total of 3 doses. They may receive a second booster of mRNA vaccine (4th dose) 4 months after their first booster dose.
The first booster dose may be any age-appropriate authorized or licensed COVID-19 vaccine; an mRNA vaccine (Pfizer-BioNTech or Moderna) is preferred. Janssen vaccine may be considered if mRNA vaccination is not feasible. If using Moderna vaccine as a booster dose, administer a 50 mcg booster dose. Only mRNA vaccines are authorized for use as a second booster dose.
CDC has produced a print-ready document outlining the clinical considerations for deciding whether to give second booster dose: www.cdc.gov/vaccines/covid-19/downloads/Clinical-Considerations-Second-COVID-19-Booster-508.pdf.
My patient takes high dose steroids and received a single dose of Janssen COVID-19 Vaccine (Johnson & Johnson) in late March 2021. He fits the definition for moderate or severe immunocompromise. Should I give him an additional primary dose of Janssen vaccine?
All recipients of a primary dose of Janssen vaccine should receive an additional primary dose of either mRNA vaccine at least 28 days later. They should then receive a booster dose of COVID-19 vaccine (preferably an mRNA vaccine) at least 2 months (8 weeks) after their additional primary dose, for a total of 3 doses. When Moderna vaccine is used as an additional primary dose, administer a 100 mcg primary series dose. When Moderna vaccine is used as a booster dose, administer a 50 mcg booster dose. Only mRNA vaccines are authorized for use as a second booster dose, which may be given at least 4 months after the first booster dose.
My patient, age 45, is immunocompromised and is recommended to receive an additional primary dose of mRNA COVID-19 vaccine, but it has already been more than 6 months since his second mRNA dose. What do I do now?
The patient should receive his third primary dose now, using the same brand as the first two doses. If the primary series is Moderna, a full 100 mcg additional primary dose should be used.
The patient should be counseled to return 3 months after the third primary dose for a booster dose (dose 4) of an authorized or licensed COVID-19 vaccine, preferably an mRNA vaccine. A second booster dose may be given at least 4 months after the first booster dose. When Moderna is used as a booster dose, administer a 50 mcg dose. Booster doses are currently recommended only for people age 12 years and older.
My patient is medically complex and severely immunocompromised and our clinical team has concerns that the recommended schedule of COVID-19 vaccination for immunocompromised patients may not be adequate. Does CDC permit any latitude in the COVID-19 vaccination schedule for such patients?
CDC's interim clinical considerations now state that, on a case-by-case basis, providers caring for moderately or severely immunocompromised patients may administer mRNA COVID-19 vaccines outside of the FDA and CDC dosing intervals based on clinical judgment when the benefits of vaccination are deemed to outweigh the potential and unknown risks for the recipient. However, CDC cautions that providers should not routinely administer doses of COVID-19 vaccine beyond those recommended.
Administering Vaccines Back to top
How are COVID-19 vaccines administered?
CDC has prepared a quick reference guide for preparation and administration of each COVID-19 vaccine:
Pfizer-BioNTech COVID-19 Vaccine, age 12 years and older (purple cap, dilute before use): www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/downloads/prep-and-admin-summary.pdf.
Pfizer-BioNTech COVID-19 Vaccine, age 12 years and older (gray cap, do not dilute): www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/downloads/gray-cap-prep-and-admin-summary.pdf
  Pfizer-BioNTech COVID-19 Vaccine, age 5 through 11 years (orange cap, dilute before use): www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/downloads/Pfizer_PED_PrepAdmin.pdf.
  Moderna COVID-19 Vaccine: www.cdc.gov/vaccines/covid-19/info-by-product/moderna/downloads/prep-and-admin-summary.pdf
  Janssen COVID-19 Vaccine: www.cdc.gov/vaccines/covid-19/info-by-product/janssen/downloads/Janssen-Prep-and-Admin-Summary.pdf
Has CDC provided clinical guidance on what to do if an error occurs while administering COVID-19 vaccinations?
Yes. CDC has published an appendix to its interim clinical considerations for the use of COVID-19 vaccines to address a wide range of errors in vaccine administration. It includes a detailed table outlining actions to take after an error has occurred: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#appendix-c.
The summary table of COVID-19 vaccination errors and how to address them is also available from CDC as a print-ready document: www.cdc.gov/vaccines/covid-19/downloads/covid19-vaccine-errors-deviations.pdf.
Errors addressed include the following:
Incorrect route or site
  Incorrect age (including administration of a formulation or brand of vaccine to a person in an age group not authorized or approved for that vaccine)
  Incorrect dosing interval
  Incorrect dose (high or low)
  Administration after improper storage conditions
  Administration after the expiration/beyond use date
  Diluent errors (wrong diluent, too much or too little) with the Pfizer-BioNTech vaccines
Ask the Experts refers our readers to these CDC resources for the most current and comprehensive guidance on COVID-19 vaccine administration errors and how to manage them.
A dose of COVID-19 vaccine was administered subcutaneously instead of by the intramuscular route. Does the dose need to be repeated?
No. CDC does not recommend repeating the dose of any COVID-19 vaccine in circumstances where the dose is administered in an incorrect route or an incorrect site (i.e., not in the deltoid or anterolateral thigh).
During vaccination, the needle came loose and vaccine leaked out around it. Do we need to repeat the dose?
It depends on how much of the dose was successfully administered. If, in your judgment, the patient received at least half of the vaccine dose, do not repeat the dose. However, if you judge that less than half the dose was administered, revaccinate the recipient immediately (no minimum interval) with a full dose in the opposite arm.
Scheduling Vaccines Back to top
Where can I find the latest information on scheduling COVID-19 vaccines?
The recommended schedule of COVID-19 vaccines has evolved over time. For the current COVID-19 vaccine schedule, including graphics and charts, refer to the CDC's interim clinical considerations for COVID-19 vaccination: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#recommendations.
What is the recommended primary series schedule for mRNA COVID-19 vaccines?
In addition to the web site provided above, CDC has summarized the recommended vaccination schedule for each available product for all people age 5 years and older in a print-ready PDF document: www.cdc.gov/vaccines/covid-19/downloads/COVID-19-immunization-schedule-ages-5yrs-older.pdf.
Always check the date at the bottom of the document after new changes are announced to be sure you are using the most current version. You may also verify whether you are using the most current documents by checking Immunize.org's regularly updated Checklist of Current Versions of U.S. COVID-19 Vaccination Guidance and Clinic Support Tools: www.immunize.org/catg.d/p3130.pdf.
If a patient does not come back on time for the second dose of an mRNA COVID-19 vaccine, do we need to re-start the vaccine series?
No. Regardless of the interval, simply administer the second dose to complete the series.
What if the patient gets the second dose of an mRNA COVID-19 vaccine early?
Primary series or additional primary series doses administered more than 4 days before the recommended interval should be repeated after the recommended minimum interval between doses: 21 days between Pfizer-BioNTech dose 1 and dose 2; 28 days between Moderna dose 1 and dose 2; 28 days between dose 2 and dose 3 for patients requiring an additional primary series dose of either product. Doses administered within a grace period of 4 days or fewer from the recommended date are considered valid and do not need to be repeated. A booster dose that is administered before the recommended minimum booster dose interval does not need to be repeated.
If the second dose of mRNA COVID-19 vaccine may be given before the recommended interval because of the 4-day grace period, should we offer that option routinely?
No. People should not be scheduled to receive dose 2 earlier than recommended (21 days for Pfizer-BioNTech, 28 days for Moderna). Schedulers should offer second dose appointments beginning on the date of the recommended interval or later. CDC guidance allows for dose 2 to be given up to 4 days before the recommended interval in order to avoid missed vaccination opportunities when a recipient unexpectedly arrives early and might not return on schedule. The series never needs to be restarted due to a delay in the second dose.
If a patient inadvertently received a different brand of mRNA vaccine as a second dose, does it need to be repeated with the correct brand?
If a recipient is inadvertently given a different brand of mRNA vaccine for the second dose, the CDC does not recommend that the patient receive a repeat dose of either product.
If a patient received a dose of mRNA COVID-19 vaccine, but cannot obtain a second dose of the original brand of mRNA vaccine, what should we do?
Once a series is initiated, the first choice is to complete the mRNA COVID-19 vaccine series with the same brand. In exceptional circumstances where the same brand cannot be obtained, the series may be completed with a different mRNA brand.
Only in exceptional situations where no second dose of mRNA COVID-19 vaccine may be given, a single dose of Janssen COVID-19 vaccine may be considered at a minimum interval of 28 days from the mRNA COVID-19 vaccine dose for recipients age 18 years or older. As part of a pre-vaccination discussion, all who elect to receive a Janssen COVID-19 Vaccine booster should be informed about the risk and symptoms of thrombosis with thrombocytopenia syndrome (TTS), and the need to seek immediate medical care should TTS symptoms develop. People who receive the Janssen COVID-19 vaccine after a dose of an mRNA COVID-19 vaccine should be considered to have received a valid, single-dose Janssen vaccination–not a mixed vaccination series.
What is the recommended first and second booster dose schedule for recipients of an mRNA COVID-19 vaccine primary series?
As of January 5, 2022, ACIP recommends that all people age 12 years or older who completed a primary series of an mRNA COVID-19 vaccine should receive a booster dose of an age-appropriate COVID-19 vaccine (preferably an mRNA vaccine) at least 5 months after completing the primary series, unless they are moderately or severely immunocompromised. Those who are moderately or severely immunocompromised should receive their booster dose at least 3 months after the third dose of their primary series. Currently, CDC does not recommend a booster dose in children younger than age 12 years.
Certain people who receive a first booster dose may choose to receive a second booster dose at least 4 months after the first booster. Those eligible for a second booster dose include all people age 50 years or older and all people age 12 years or older who are moderately or severely immunocompromised. CDC has produced a print-ready document (PDF) outlining the clinical considerations for a second booster dose in certain people: www.cdc.gov/vaccines/covid-19/downloads/Clinical-Considerations-Second-COVID-19-Booster-508.pdf.
What is the recommended booster dose schedule for recipients of the Janssen (Johnson & Johnson) COVID-19 Vaccine?
People age 18 years or older who received the single dose of Janssen COVID-19 Vaccine (Johnson & Johnson) primary series should receive a single COVID-19 booster dose (an mRNA vaccine, unless use of an mRNA vaccine is not feasible) at least 2 months (8 weeks) after the Janssen COVID-19 single primary dose. Those who are moderately or severely immunocompromised and receive a single Janssen primary dose should receive an additional primary dose of mRNA vaccine at least 28 days later, followed by a booster dose at least 2 months (8 weeks) after the additional primary dose, for a total of 3 doses. A second booster dose, administered at least 4 months after the first, may be considered for those who are moderately or severely immunocompromised or those who are age 50 years or older.
CDC has produced a print-ready document (PDF) outlining the clinical considerations for a second booster dose in eligible people: www.cdc.gov/vaccines/covid-19/downloads/Clinical-Considerations-Second-COVID-19-Booster-508.pdf.
What are COVID-19 Vaccine Emergency Use Instructions (EUI) and to whom do they apply?
CDC has issued emergency use instructions (EUI) for the use of the FDA-licensed mRNA vaccines (adolescent/adult Pfizer-BioNTech COVID-19 Vaccine [Comirnaty] or Moderna COVID-19 Vaccine [Spikevax]), that differ from the FDA-approved package insert. These instructions apply to certain people who received primary series COVID-19 vaccination with vaccines not authorized or approved by the FDA (either in another country or as part of a clinical trial) and to people who may need revaccination following hematopoietic cell transplant (HCT) or CAR-T-cell therapy.
Vaccine schedule guidance is provided by age for the general population and for individuals with moderate or severe immunocompromise.
All CDC EUI resources, including the Pfizer-BioNTech and Moderna EUI Fact Sheets for Healthcare Providers, as well as those for recipients and caregivers (available in English and Spanish), are at this site: www.cdc.gov/vaccines/covid-19/eui/index.html.
We have a patient who was vaccinated with a COVID-19 vaccine in another country. What do we do?
CDC has issued a detailed set of emergency use instructions (EUI) that provides a legal framework for the use of licensed COVID-19 vaccines to vaccinate people who have received vaccines not authorized or licensed in the United States. A key factor in determining next steps is whether or not the vaccine administered in another country is listed for emergency use by the World Health Organization (WHO-EUL), which signals that the vaccine has been reviewed and considered acceptable for use by WHO experts.
CDC has outlined each vaccination option on its website. For specific cases, please review CDC's detailed EUI table here: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#appendix-a.
A list of the vaccines that have already received WHO-EUL status is available here: https://extranet.who.int/pqweb/vaccines/vaccinescovid-19-vaccine-eul-issued.
My patient was vaccinated in a clinical trial with a vaccine that is not yet authorized for use by the FDA. How should we evaluate his need for vaccination now?
People vaccinated as part of a clinical trial with a vaccine not authorized or approved for use in the United States are covered under the CDC's Emergency Use Instructions (EUI).
CDC has provided specific guidance for evaluating the current vaccination needs of people who participated in a COVID-19 vaccine clinical trial here: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#appendix-b.
What should be done if a patient scheduled for vaccination is exposed to COVID-19 and quarantined or is isolated for suspected or confirmed SARS-CoV-2 infection?
In general, the people scheduled for COVID-19 vaccination who are exposed to SARS-CoV-2 virus and quarantined should reschedule vaccination after their quarantine period has ended in order to avoid the risk of exposing vaccinators to the virus.
People diagnosed with SARS-CoV-2 infection before a scheduled vaccination should defer vaccination until after recovery and the end of the isolation period to avoid the risk of exposing vaccinators to the virus. Early in 2021, when vaccines were scarce, such individuals were advised to defer vaccination up to 90 days after infection to allow the targeted use of scarce vaccines for more susceptible people at high risk; however, no waiting period for vaccination beyond recovery is recommended now that vaccine supply is not constrained.
Residents or patients with a known COVID-19 exposure in congregate healthcare settings (e.g., long-term care facilities) or congregate non-healthcare settings (e.g., correctional facilities, homeless shelters) may be vaccinated. In these settings, exposure to and transmission of SARS-CoV-2 can occur repeatedly for long periods of time, and healthcare personnel and other staff are already in close contact with residents. People residing in congregate settings (healthcare and non-healthcare) who have had an exposure and are awaiting SARS-CoV-2 testing results may be vaccinated if they do not have symptoms consistent with COVID-19. Vaccinators should employ appropriate infection prevention and control procedures.
Can COVID-19 vaccine recipients be given other vaccines at the same visit?
Yes. COVID-19 vaccines and other vaccines may be administered without regard to timing.
Until May 2021, COVID-19 vaccines were recommended to be administered alone, with a minimum interval of 14 days before or after administration of any other vaccines. This was out of an abundance of caution and not due to any known safety concerns or concerns about interference with effectiveness. Limited data are available for COVID-19 vaccines administered simultaneously with other vaccines: a study of COVID-19 vaccine coadministered with high-dose inactivated influenza vaccine showed no difference in the immune response to either vaccine and no significant increase in local or systemic side effects when compared to administering the vaccines at separate visits. Extensive experience with non-COVID-19 vaccines has demonstrated that the immune response and side effects following vaccination are generally similar when vaccines are administered simultaneously and when vaccines are administered alone.
My patient is due for a second dose of recombinant zoster vaccine (Shingrix, GSK). However, the patient is eligible to receive COVID-19 vaccine and wants to be vaccinated against COVID-19 as soon as possible. What should we advise our patient about scheduling the second Shingrix dose?
Your patient may choose to receive the vaccines at the same visit or separately, without regard to the timing interval. It is unknown whether side effects would be increased with coadministration. In general, when deciding whether to coadminister other vaccines with COVID-19 vaccine, you should consider whether the patient is behind or at risk of becoming behind on recommended vaccines, their risk of vaccine-preventable disease (e.g., during an outbreak or occupational exposures), and the reactogenicity profile of the vaccines.
When multiple vaccines are administered at a single visit, administer each injection in a different injection site. For adolescents and adults, the deltoid muscle may be used for more than one injection, though injection sites should be at least one inch apart. It is generally preferable to administer reactogenic vaccines such as Shingrix and COVID-19 vaccine in different arms, if possible. If the patient prefers both injections in the same deltoid, that is also acceptable.
Immunize.org has developed a one-page guide to administering multiple intramuscular vaccinations to an adult at one visit: www.immunize.org/catg.d/p2030.pdf.
A patient had a routine tuberculin skin test (TST) placed the day before the patient's appointment for a COVID-19 vaccine. Should we proceed with vaccination or do we need to reschedule?
CDC now advises that COVID-19 vaccination should not be delayed because of testing for tuberculosis (TB) infection. Testing for TB infection with one of the immune-based methods, either the tuberculin skin test (TST) or an interferon-gamma release assay (IGRA), can be done before, after, or during the same encounter as COVID-19 vaccination: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#special-populations.
How does the use of monoclonal antibodies or convalescent plasma to treat or prevent COVID-19 affect the scheduling of COVID-19 vaccination?
In February 2022, CDC updated its guidance on the scheduling of COVID-19 vaccination around monoclonal antibodies or convalescent plasma. CDC now recommends that COVID-19 vaccination does NOT need to be delayed following receipt of monoclonal antibodies or convalescent plasma.
In people who previously received a COVID-19 vaccine, administration of tixagevimab/cilgavimab (Evusheld, AstraZeneca) for pre-exposure prophylaxis (PrEP) should be deferred for at least two weeks after vaccination, per the product's emergency use authorization.
Contraindications and Precautions Back to top
Please describe the contraindications for each COVID-19 vaccination.
We refer our readers to CDC's updated set of contraindications and precautions to vaccination with COVID-19 vaccines, located in table 4 of its interim clinical considerations for the use of COVID-19 vaccines in the United States: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#contraindications.
What are the precautions to COVID-19 vaccination?
We refer our readers to CDC's updated set of contraindications and precautions to COVID-19 vaccination, located in table 4 of its interim clinical considerations for the use of COVID-19 vaccines: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#contraindications.
Can people who are immunocompromised or who have autoimmune disease be vaccinated with mRNA COVID-19 vaccines?
Yes, they may be vaccinated as long as they do not have a contraindication to vaccination. Antibody testing is not recommended to assess for immunity to SARS-CoV-2 following COVID-19 vaccination.
People should be counseled about the unknown vaccine effectiveness in immunocompromised populations and the potential for reduced immune responses. They should maintain other practices, such as wearing a mask in public and avoiding crowds, to reduce their risk of exposure to SARS-CoV-2. Children and adults age 5 years or older with moderate or severe immunocompromise who have received a 2-dose primary series of mRNA or a single primary dose of Janssen vaccine are recommended to receive an additional primary dose of mRNA vaccine at least 28 days later.
If age 12 years or older, after receiving a 3-dose primary series of mRNA primary series, the patient should receive an age-appropriate booster dose (preferably an mRNA vaccine) 3 months later. If age 18 years or older, after receiving a Janssen vaccine and an additional mRNA vaccine, the patient should receive a booster dose (preferably an mRNA vaccine) 2 months later. If age 12 or older, a second booster dose may be given at least 4 months following the first booster dose. See detailed considerations for vaccination of people with moderate or severe immunocompromise here: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#immunocompromised.
Are there any common types of allergies that are neither contraindications nor precautions to vaccination?
Allergic reactions (including severe allergic reactions) not related to vaccines (COVID-19 or other vaccines) or injectable therapies, such as allergic reactions related to food, pet, venom, or environmental allergies, or allergies to oral medications (including the oral equivalents of injectable medications), are not a contraindication or precaution to COVID-19 vaccination. The vial stoppers of COVID-19 vaccines are not made with natural rubber latex, and there is no contraindication or precaution to vaccination for people with a latex allergy. COVID-19 vaccines do not contain eggs, gelatin, or metals.
A self-limited, delayed-onset local reaction around the injection site ("COVID arm") has been reported by some mRNA vaccine recipients several days after vaccination (see next question). This type of reaction is not a precaution or contraindication to future doses of the same vaccine.
A vaccine recipient reported experiencing a red, itchy, swollen patch of skin that developed several days after vaccination around the injection site of her first COVID-19 vaccine dose. It resolved after a few days. Is this a contraindication? Should this alter our plans for dose two?
This condition is not rare and is also known as "COVID arm". She should receive dose two as recommended. Individuals with only a delayed-onset local reaction (e.g., redness, induration, itching) around the injection site area after the first vaccine dose do not have a contraindication or precaution to the second dose.
These delayed-onset local reactions are sometimes quite large but are self-limited. It is not known whether individuals who experienced a delayed-onset injection site reaction after the first dose will experience a similar reaction after the second dose. However, these reactions are not believed to represent an increased risk for anaphylaxis after a subsequent dose. Thus, individuals with such delayed injection site reactions after the first mRNA COVID-19 vaccine dose should receive the second dose using the same vaccine product as the first dose and at the recommended interval, preferably in the opposite arm.
Patients who experience "COVID arm" may take an antihistamine if it is itchy or a pain medication such as acetaminophen or a non-steroidal anti-inflammatory (NSAID) if it is painful.
Patients concerned about the risk of allergic reaction or side effects following COVID-19 vaccination are asking if they should take acetaminophen, aspirin, and/or antihistamines before receiving COVID-19 vaccination. What does CDC advise?
Medications to reduce fever and pain (e.g., acetaminophen, non-steroidal anti-inflammatory drugs) may be taken to treat post-vaccination local or systemic symptoms, if medically appropriate. However, routine administration of such medications before vaccination is not recommended because information on the impact of such use on COVID-19 vaccine-induced antibody responses is not available at this time.
Administration of antihistamines before COVID-19 vaccination to prevent allergic reactions is not recommended. Antihistamines do not prevent anaphylaxis, and their use might mask cutaneous symptoms, which could delay diagnosis and management of anaphylaxis.
It is not recommended that people take aspirin or an anticoagulant before vaccination with the Janssen COVID-19 vaccine or any other FDA-authorized COVID-19 vaccine unless they take these medications as part of their routine medications.
Is COVID-19 vaccination contraindicated in a patient who has had immune-mediated thrombosis with thrombocytopenia syndrome (TTS)?
It is contraindicated to administer Janssen COVID-19 Vaccine to persons with a history of TTS following receipt of the Janssen COVID-19 Vaccine or any other adenovirus vector-based COVID-19 vaccines (e.g., AstraZeneca COVID-19 Vaccine, which is not authorized or approved in the United States). Individuals who have experienced TTS following Janssen COVID-19 Vaccine may be vaccinated with a booster dose of mRNA vaccine 2 months (8 weeks) after receipt of the Janssen vaccine, if their clinical condition is stabilized. Individuals with a history of an episode of an immune-mediated TTS, such as HIT, should be offered an mRNA COVID-19 vaccine.
Additional clinical considerations concerning the use of Janssen COVID-19 Vaccine are available from CDC here: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#considerations-Janssen.
My patient has a history of deep venous thrombosis (DVTs). Is that a precaution or contraindication to vaccination with the Janssen COVID-19 Vaccine?
Venous thromboembolism (VTE), defined as deep vein thrombosis, pulmonary embolism, or both, are common. The biologic mechanisms for VTE (as well as arterial thrombi) differ from the underlying immune-mediated mechanism for thrombosis with thrombocytopenia syndrome (TTS). Experts believe that the presence of risk factors for VTE does not make individuals more susceptible to TTS after vaccination with the Janssen vaccine. As with the general population, mRNA vaccines are preferred over Janssen vaccine for these recipients.
Is there a precaution or contraindication against vaccination of children or adults who have recovered from COVID-19 Multisystem Inflammatory Syndrome (MIS-C or MIS-A)?
There are limited data on the safety of COVID-19 vaccines in people who have had MIS-C or MIS-A from SARS-CoV-2 infection and who have not yet received COVID-19 vaccine. Case-by-case consultation with their clinical team or a specialist (e.g., specialist in infectious diseases, rheumatology, or cardiology) is strongly encouraged. CDC continues to update its clinical considerations for vaccination of children or adults who have experienced MIS-C or MIS-A. Visit this link for the most current clinical considerations for vaccination of children and adults who have experienced this syndrome following SARS-CoV-2 infection: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#infection.
My patient had an episode of myocarditis 5 years ago. Is a history of myocarditis a contraindication or precaution to vaccination with an mRNA vaccine?
CDC guidance is that people who have a history of myocarditis or pericarditis unrelated to mRNA COVID-19 vaccination (e.g., due to SARS-CoV-2 or other viruses) may receive any currently FDA-approved or FDA-authorized COVID-19 vaccine after the episode of myocarditis or pericarditis has completely resolved. This includes resolution of symptoms attributed to myocarditis or pericarditis, as well as no evidence of ongoing heart inflammation or sequelae as determined by the person's clinical team.
For mRNA COVID-19 vaccines, history of myocarditis or pericarditis after a dose of an mRNA COVID-19 vaccine is a precaution to vaccination with any COVID-19 vaccine.
For additional information about myocarditis and mRNA COVID-19 vaccines, visit www.cdc.gov/vaccines/covid-19/clinical-considerations/myocarditis.html.
My patient has a history of Guillain-Barré syndrome (GBS). Is that a contraindication or precaution to vaccination with any COVID-19 vaccine?
People with a history of GBS can receive any currently FDA-authorized or licensed COVID-19 vaccine; as with the general population, mRNA vaccines are preferred to the Janssen COVID-19 Vaccine. Vaccine safety monitoring suggests an elevated risk of GBS in the 42 days following the Janssen COVID-19 Vaccine, with the highest risk observed in people ages 40 through 64 years. Most reports of GBS have been in males. The risk of this very rare outcome is clearly outweighed by the benefits of vaccination with a COVID-19 vaccine, including Janssen COVID-19 Vaccine in exceptional situations when vaccination with an mRNA vaccine is not possible.
Vaccine Safety Back to top
What side effects are expected after vaccination with mRNA vaccines?
Recipients of mRNA COVID-19 vaccines often experience local (e.g., pain, swelling, redness at the injection site, localized swollen lymph nodes in the armpit of the vaccinated arm) or systemic (e.g., fever, fatigue, headache, chills, body and joint aches) post-vaccination symptoms. Depending on vaccine product (Pfizer-BioNTech vs. Moderna), age group, and vaccine dose, approximately 80–91% of vaccinated people develop at least one local symptom and 55–91% develop at least one systemic symptom following vaccination.
Most systemic post-vaccination symptoms are mild to moderate in severity, occur within the first three days of vaccination, and resolve within 1–3 days of onset. These symptoms are more frequent and severe following the second dose and among younger people compared to older people. Children age 5 through 11 years who receive the reduced dose (10 mcg) orange cap Pfizer-BioNTech COVID-19 Vaccine reported milder side effects, including less fever, than individuals age 12 years and older who receive the 30 mcg adolescent/adult dose.
What common side effects are expected after vaccination with Janssen COVID-19 Vaccine (Johnson & Johnson)?
Recipients of the Janssen viral vector vaccine in the phase 3 clinical trial often experienced local or systemic post-vaccination symptoms, though the majority of reported symptoms were mild to moderate in severity and resolved within 1 to 3 days after vaccination. The frequency of any local reaction was higher in participants aged 18 to 59 years than participants age 60 years or older (59.8% vs 35.4%). Pain at the injection site was the most frequently reported solicited local reaction. The frequency of systemic reactions was higher in participants age 18–59 years than participants 60 years or older (61.5% vs 45.3%). For both age groups, fatigue and headache were the most commonly reported systemic reactions. Fever was more common in participants 18–59 years (12.8%) compared to those 60 years or older (3.1%).
What is the thrombosis with thrombocytopenia syndrome, called TTS, associated with the Janssen COVID-19 Vaccine?
TTS is a rare, immune-mediated syndrome that involves acute venous or arterial thrombosis (blood clot) and new onset thrombocytopenia (low platelet count) in patients with no recent known exposure to heparin. The onset of TTS is typically 1 to 2 weeks following vaccination; treatment with heparin, a common anticoagulant used to treat blood clots, worsens the condition. In the U.S., the majority of people with TTS after Janssen COVID-19 vaccination had clots located in cerebral venous sinuses; clots occurred in other unusual locations including in the portal vein and splenic vein, and also included a combination of venous and arterial thromboses.
Cases of TTS following administration of the Janssen COVID-19 Vaccine have been reported in males and females, in a wide age range of individuals 18 years and older, with the highest reporting rate (approximately 1 case per 100,000 doses administered) in females ages 30-49 years; overall, approximately 15% of TTS cases have been fatal.
Based on an updated risk-benefit analysis, including the risk of TTS, use of mRNA COVID-19 vaccines is preferred over the Janssen COVID-19 vaccine for all vaccine-eligible people. The FDA EUA for Janssen vaccine limits its authorized use to people for whom mRNA vaccines are clinically inappropriate or those for whom mRNA vaccination is not feasible. All people who elect to receive a Janssen COVID-19 vaccine booster should be informed about the risk and symptoms of TTS that could occur after vaccination (typically within 2 weeks after receipt), the need to seek immediate medical care should such symptoms develop at any time, and the availability of mRNA COVID-19 vaccines instead of the Janssen COVID-19 Vaccine.
What are the symptoms of TTS and where can I learn more about treatment?
Cases of TTS following administration of the Janssen COVID-19 Vaccine have been reported in males and females, in a wide age range of individuals 18 years and older, with the highest reporting rate (approximately 1 case per 100,000 doses administered) in females ages 30-49 years; overall, approximately 15% of TTS cases have been fatal. Symptom onset typically begins 1 to 2 weeks after vaccination. People should seek medical attention right away if they have any of the following symptoms after receiving the Janssen vaccine:
Shortness of breath
  Chest pain
  Leg swelling
  Persistent abdominal pain
  Severe or persistent headaches or blurred vision
  Easy bruising or tiny blood spots under the skin beyond the site of the injection
Treatment of TTS is different from the treatment of typical blood clots; heparin should be avoided in any patient suspected of TTS until the diagnosis can be ruled out.
For additional clinical guidance, see the CDC Health Alert Network Report from April 13, 2021: emergency.cdc.gov/han/2021/han00442.asp and treatment guidelines from the American Society for Hematology: www.hematology.org/covid-19/vaccine-induced-immune-thrombotic-thrombocytopenia.
Have any COVID-19 vaccines been associated with Guillain-Barré syndrome (GBS)?
Vaccine safety monitoring indicates an increased risk of GBS within 42 days of vaccination with the Janssen COVID-19 Vaccine, with the highest risk among people ages 40 through 64. Most reports have been in males. Although the chance of GBS occurring is extremely low, Janssen vaccine recipients should be counseled to seek medical attention promptly if symptoms of GBS occur, such as progressive muscle weakness. Currently, no association has been observed between GBS and mRNA COVID-19 vaccines.
Patients with a history of GBS may receive Janssen COVID-19 Vaccine if vaccination with an mRNA vaccine is not possible, but, as with the general population, mRNA vaccines should be administered unless use of an mRNA vaccine is not feasible.
Patients who experienced GBS after Janssen COVID-19 vaccination should be informed of the recommendation for a booster dose 2 months after the first dose and the preferred option to receive an mRNA vaccine. Discussions with the clinical team for the patient are encouraged to assist decision-making.
I have both mRNA and Janssen vaccines available. Now that mRNA vaccines are preferred and FDA has limited the use of Janssen vaccine, when should I offer the Janssen vaccine?
Use of mRNA COVID-19 vaccines is preferred over the Janssen COVID-19 vaccine for all vaccine-eligible people except in situations where use of an mRNA vaccine is not feasible, as described below:
When there is a contraindication to mRNA COVID-19 vaccines (e.g., severe allergic reaction after a previous dose or to a component of an mRNA COVID-19 vaccine)
  When a person would otherwise remain unvaccinated for COVID-19 due to lack of access to mRNA COVID-19 vaccines
  When a person refuses mRNA vaccination and chooses to receive the Janssen COVID-19 Vaccine despite the safety concerns identified
All people who elect to receive a Janssen COVID-19 vaccine booster should be informed about the risk and symptoms of TTS that could occur after vaccination (typically within 2 weeks after receipt), the need to seek immediate medical care should such symptoms develop at any time, and the availability of mRNA COVID-19 vaccines instead of the Janssen COVID-19 Vaccine.
Can COVID-19 vaccination lead to fertility problems?
There is no evidence that any of the COVID-19 vaccines affect current or future fertility.
Tell me about mRNA COVID-19 vaccines and the risk of myocarditis and pericarditis.
A rare risk for myocarditis (inflammation of the heart muscle) and/or pericarditis (inflammation of the tissue surrounding the heart) has been observed following receipt of mRNA COVID-19 vaccines. These rare cases of myocarditis or pericarditis have occurred most frequently in adolescent and young adult males within the first week after receiving the second dose of an mRNA COVID-19 vaccine. The risk appears lower following a booster dose. Myocarditis has been rarely reported in children ages 5 through 11 years after COVID-19 vaccination; it is unclear whether there is an increased risk due to vaccination in that age group. Most patients with myocarditis after mRNA COVID-19 vaccination have been hospitalized for short periods, with most completely recovering from their acute symptoms. CDC is assessing long-term outcomes in people with myocarditis after mRNA COVID-19 vaccination.
People receiving mRNA vaccines, especially males age 12 through 39, should be counseled about the risk of myocarditis or pericarditis and advised to seek medical attention promptly if they develop chest pain, shortness of breath, or feelings of a fast, fluttering, or pounding heartbeat.
Evidence from other countries indicates that waiting 8 weeks to administer the second mRNA dose can significantly reduce the risk of myocarditis following dose 2; antibody levels after dose 2 may also be higher when given after an 8-week interval. CDC now recommends that an 8-week interval may be optimal for some people age 12 through 64 years. CDC does not recommend the 8-week dose interval for children under 12 years, or for people who need rapid protection from COVID-19, including adults 65 or older, people with moderate to severe immunocompromise, and in circumstances where rapid protection is desired due to high levels of circulating COVID-19.
CDC has published additional clinical considerations for the evaluation and care of patients with myocarditis or pericarditis following mRNA vaccination: www.cdc.gov/vaccines/covid-19/clinical-considerations/myocarditis.html.
How should patients with allergies presenting for COVID-19 vaccination be evaluated?
Serious allergic reactions, such as anaphylaxis, in the minutes following vaccination are rare but are possible with any vaccine. Every vaccination site should have staff available who are trained and equipped to recognize and respond to signs of anaphylaxis in a vaccine recipient. See this CDC website for additional information about preparing for the management of anaphylaxis: www.cdc.gov/vaccines/covid-19/clinical-considerations/managing-anaphylaxis.html?anaphylaxis-management.html.
Anaphylaxis following vaccination with mRNA COVID-19 vaccines is reported at a rate of approximately 2 to 5 cases per million doses administered.
An immediate allergic reaction to any component or previous dose of an mRNA COVID-19 vaccine is a contraindication to vaccination with both the Pfizer-BioNTech and Moderna vaccines; however, use of the Janssen viral vector vaccine may not be contraindicated (see the COVID-19 section on contraindications and precautions for details). Please see this CDC chart of vaccine components designed to assist the triage of patients with various health conditions or allergies: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#appendix-f.
How long should patients be observed for signs of an immediate allergic reaction following vaccination with a COVID-19 vaccine?
People with a history of an immediate allergic reaction of any severity to a vaccine or injectable therapy and people with a history of anaphylaxis due to any cause should be observed for 30 minutes. People with a contraindication to a different type of COVID-19 vaccine should be observed for 30 minutes following vaccination (for example, people with a contraindication to mRNA COVID-19 vaccines who receive Janssen viral vector vaccine should be observed for 30 minutes following Janssen vaccination). All other people should be observed for 15 minutes.
Where can I find the latest information on allergic reactions and COVID-19 vaccines?
Visit this CDC website for the latest information: www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/allergic-reaction.html.
I have heard that the FDA has specific reporting requirements for healthcare providers who administer COVID-19 vaccines under EUA. What are they?
Adverse events that occur in a recipient following COVID-19 vaccination should be reported to the Vaccine Adverse Event Reporting System (VAERS). Vaccination providers are required by the FDA to report the following that occur after COVID-19 vaccination under Emergency Use Authorization:
All vaccine administration errors
  Serious adverse events, including TTS, GBS, or myocarditis
  Cases of Multisystem Inflammatory Syndrome (MIS-C or MIS-A)
  Cases of COVID-19 that result in hospitalization or death
Reporting is encouraged for any other clinically significant adverse event even if it is uncertain whether the vaccine caused the event. Information on how to submit a report to VAERS is available at https://vaers.hhs.gov or by calling 1-800-822-7967.
How is the safety of COVID-19 vaccines being monitored?
Multiple national surveillance systems are being used to monitor the safety of new COVID-19 vaccines in different ways. Please see this CDC website for additional information on each system: www.cdc.gov/coronavirus/2019-ncov/vaccines/safety.html.
What is v-safe?
CDC's v-safe program is a smartphone-based tool that uses text messaging and web surveys to provide personalized health check-ins after a person receives a COVID-19 vaccination. It also provides second dose reminders. Participation is voluntary; pregnant individuals are especially encouraged to participate in the v-safe pregnancy registry. Vaccine recipients may sign up for the program after receiving the first dose. For more information, visit www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/vsafe.html.
Is compensation for an injury resulting from an EUA COVID-19 vaccine available through the National Vaccine Injury Compensation Program (VICP)?
No. The COVID-19 vaccines are not part of the VICP. The COVID-19 vaccines are part of a similar program called the Countermeasures Injury Compensation Program (CICP). For more information, visit this web page: www.hrsa.gov/cicp.
Storage and Handling Back to top
Where can I find details about the storage and handling of COVID-19 vaccines?
You may find guidance on the storage and handling of each authorized or licensed COVID-19 vaccine in the CDC's Vaccine Storage and Handling Toolkit addendum on COVID-19 vaccines: www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.
CDC also has produced a printable quick reference guide summarizing the storage and handling requirements for each authorized COVID-19 vaccine: www.cdc.gov/vaccines/covid-19/downloads/covid19-vaccine-quick-reference-guide-2pages.pdf
Immunize.org has assembled key COVID-19 vaccine storage and handling resources in its section on Clinic Resources and Tools at our "Vaccines: COVID-19" main page: www.immunize.org/covid-19/#tools.
How do we keep track of the Pfizer-BioNTech COVID-19 Vaccine storage requirements?
The storage and handling requirements of each formulation of the Pfizer-BioNTech COVID-19 vaccine are different, they have changed over time, and they require close attention to detail to avoid errors. Pfizer-BioNTech has produced a summary table comparing and contrasting the three available formulations of its COVID-19 vaccine: www.cvdvaccine-us.com/images/pdf/Vaccine-Formulation-Presentation-Guide.pdf.
The purple cap (dilute before use) formulation of Pfizer-BioNTech COVID-19 Vaccine for people age 12 years and older may be stored long term in an ultra-low temperature freezer (ULT, between -80°C and -60°C [-112°F and -76°F]) for up to 12 months after the manufacturing date on the label. It is permissible to store the vaccine in a standard freezer between -25°C and -15°C (-13°F to 5°F) for up to 2 weeks before use or before storing in the refrigerator. Once thawed, it may be stored at refrigerated temperatures, between 2°C and 8°C (36°F and 46°F), for up to 1 month (31 days). Storage and handling information is summarized for the purple cap (dilute before use) formulation: www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/downloads/storage-summary.pdf.
The gray cap (do not dilute) formulation of Pfizer-BioNTech COVID-19 Vaccine for people age 12 years and older may be stored in a ULT freezer between -80°C and -60°C [-112°F and -76°F]) for up to 12 months. This formulation may not be stored in a standard freezer at any time. Once thawed, it may be stored at refrigerated temperatures, between 2°C and 8°C (36°F and 46°F), for up to 10 weeks. Thawed vaccine should not be refrozen. Storage and handling information is summarized for the gray cap (do not dilute) formulation: www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/downloads/gray-cap-storage-summary.pdf.
The orange cap (dilute before use) Pfizer-BioNTech COVID-19 Vaccine for children age 5 through 11 years may be stored in a ULT freezer for up to 12 months. It may not be stored in a standard freezer at any time. It may be stored at refrigerated temperatures between 2°C and 8°C (36°F and 46°F) for up to 10 weeks. CDC has created a thorough storage and handling summary specifically for the orange cap formulation: www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/downloads/Pfizer_PED_StorageHandling_Summary.pdf.
Contact the manufacturer before discarding any vaccine past its expected expiration date to verify that its expiration date has not been extended. The CDC COVID-19 Vaccine Expiration Date Tracking Tool may be used to record updated expiration dates for COVID-19 vaccines in inventory. www.cdc.gov/vaccines/covid-19/downloads/expiration-tracker.pdf.
Under what conditions may we transport COVID-19 vaccines? Is transport of a partial vial or predrawn syringe ever permissible?
Although routine transportation of vaccines to different facilities is not generally recommended, there are times when this is necessary. CDC recommends transporting COVID-19 vaccine in vials and always with a continuous temperature monitoring device to ensure adherence to authorized storage times and temperatures. Because liquid mRNA COVID-19 vaccines should not be shaken vigorously, it is preferred to transport vials in their solid frozen state or to initiate transport while frozen, if they are not already thawed. Never re-freeze vaccine that is already thawed. Moderna recommends that thawed vials of liquid be cushioned to minimize agitation during transport. A partially used vial may be transported (e.g., in the process of vaccinating homebound individuals), but cannot be transferred from one provider to another nor can it be transported across state lines. Details are provided in the 2022 CDC Vaccine Storage and Handling Toolkit addendum on COVID-19 vaccines: www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.
There may be instances when the only option is to transport vaccine in a predrawn syringe. CDC refers to the U.S. Pharmacopeia (USP) guidance for transporting predrawn vaccine in syringes in the USP COVID-19 Vaccine Toolkit: Operational Considerations for Healthcare Practitioners. The complete document provides detailed guidance on COVID-19 vaccine transport and is available for download from this site: www.usp.org/covid-19/vaccine-handling-toolkit.
Back to top
This page was updated on May 15, 2022.
This page was reviewed on May 15, 2022.
 
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