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Ask the Experts: COVID-19

The COVID-19 questions were last reviewed on November 16, 2025. See CDC’s Use of COVID-19 Vaccines in the United States Interim Clinical Considerations for more information. To keep up with the current available COVID-19 resources from CDC, FDA, and Immunize.org, see Immunize.org’s Checklist of Current Versions of U.S. COVID-19 Vaccine Guidance and Clinic Support Tools, updated at least monthly. For alerts about new Immunize.org or CDC COVID-19 resources, subscribe to our weekly e-newsletter, IZ Express.

Results (93)

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 spreads mainly from person to person through respiratory droplets and small particles produced when an infected person coughs, sneezes, or talks. The virus spreads easily in crowded or poorly ventilated indoor settings. Some people who are infected have no symptoms of illness, while the severity of symptomatic illness ranges from mild to life-threatening. Older adults (especially those 75 or older) 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 a median of 3–4 days during Omicron circulation, according to CDC. People with COVID-19 are generally considered potentially infectious up to 48 hours before symptom onset and up to 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. See CDC’s clinical overview: www.cdc.gov/covid/hcp/clinical-care/covid19-presentation.html.

Last reviewed: October 18, 2026

The list of underlying health conditions and other factors shown to increase the risk of severe COVID-19 illness is long. Advanced age remains the strongest risk factor. CDC provides a list of at-risk conditions at this website: www.cdc.gov/covid/hcp/clinical-care/underlying-conditions.html. The conditions are stratified by strength of published evidence.

Immunize.org provides age-appropriate standing orders templates for COVID-19 vaccination on the COVID-19 main page: www.immunize.org/vaccines/a-z/covid-19/. These templates include the broad, general list of conditions that increase the risk of severe COVID-19 found at www.cdc.gov/covid/risk-factors/index.html.

Last reviewed: October 18, 2026

Recommendations for the use of the 2026–2027 Formula COVID-19 vaccines were issued by the American Academy of Pediatrics (AAP), American Academy of Family Physicians (AAFP), American College of Obstetricians and Gynecologists (ACOG), and the Infectious Diseases Society of America (IDSA) on September 2, 2026. Their recommendations were informed by the Vaccine Integrity Project (VIP) of the University of Minnesota and the American Medical Association (AMA), which conducted a systematic review of relevant scientific literature published since the previous season’s vaccination recommendations were made. There is no preference expressed for any product: Spikevax (mRNA, age 6 months and up), Comirnaty (mRNA, age 5 years and up), mNexspike (mRNA, age 12 years and up), and Nuvaxovid (protein subunit, age 12 years and up). 

In the 2025–26 season, CDC’s recommendation was for COVID-19 vaccination following shared clinical decision-making (a conversation about individual risks and benefits of vaccination) for all people, beginning at age 6 months.  

The 2026–27 recommendations from medical societies are summarized below: 

AAP (children through age 18 years):  

  • Age 6 through 23 months: routine use in all children.  
  • Age 2 through 18 years:  
    • at high risk of severe COVID-19, or 
    • who are residents of long-term care facilities or other congregate settings, or 
    • who have never been vaccinated against COVID-19, or 
    • whose household contacts are at high risk for severe COVID-19, or 
    • who meets none of the above conditions, but whose parent or guardian desires their protection. 

AAFP (immunocompetent adults and healthcare professionals):  

  • All adults age 19 years and older should receive a dose of 2026–2027 Formula COVID-19 vaccine.  
  • Adults age 65 years or older should receive a second dose of 2026–2027 Formula COVID-19 vaccine 6 months after the first dose to sustain protection. 
  • All healthcare personnel should be age-appropriately vaccinated. 

ACOG (pregnancy): 

  • A dose of 2026–2027 Formula COVID-19 vaccine is routinely recommended for all individuals who are pregnant, contemplating pregnancy, recently pregnant, or lactating. 

IDSA (immunocompromised people): 

  • A dose of 2026–2027 Formula COVID-19 vaccine is routinely recommended for people who are immunocompromised and, if they are moderately or severely immunocompromised, who have completed an initial vaccination series.  
  • A second booster dose can be given 2 to 6 months after dose one based on shared decision making and current levels of transmission. 
  • IDSA refers readers to previous guidance from CDC for the dosing schedules for an initial vaccination series recommended for a person with a moderate or severe immunocompromising condition. IDSA’s recommendations also give guidance for optimal timing of doses for certain subgroups based upon their disease or specific treatment. 
Last reviewed: September 23, 2026

In 2026, selected major professional medical societies chose to publish recommendations independent of CDC. Their recommendations divide up the population to ensure all people are covered.  Recommendations are available from:

CDC maintains a webpage with interim clinical considerations for vaccination of eligible recipients: www.cdc.gov/covid/hcp/vaccine-considerations/. This covers important clinical details about COVID-19 vaccination. As of October 13, 2026, CDC states that the recommendations from its July 2025 immunization schedule remain in effect for the 2026–27 season; its September 23, 2026, clinical considerations incorporate current vaccine products and identify CDC-recommended uses that are off-label.

Due to political interference with the work of CDC since early 2025, many healthcare professionals have favored medical society recommendations. Immunize.org continues to reference and support CDC guidance when the published information remains valid. Most of the content of the CDC clinical considerations is unchanged and remains relevant guidance for clinicians that may not readily be found elsewhere.

All of CDC’s Advisory Committee on Immunization Practices (ACIP) vaccine recommendations published in MMWR can be accessed here: www.cdc.gov/acip-recs/hcp/vaccine-specific/covid-19.html. FDA provides current package inserts here: www.fda.gov/vaccines-blood-biologics/approved-products/vaccines-licensed-use-united-states.

Last reviewed: October 18, 2026

AAP routinely recommends vaccination for all children age 6 through 23 months. For ages 2 through 18 years, AAP recommends vaccination for children at increased risk of severe COVID-19, residents of congregate settings, children who have never been vaccinated, and those with high-risk household contacts. AAP recommends offering vaccination to other children whose parent or guardian desires protection. CDC uses shared clinical decision-making for children age 6 months through 17 years without moderate or severe immunocompromise; CDC recommends vaccination for all adults starting at age 18.

Both AAP and CDC recommend vaccination for children with moderate or severe immunocompromise. AAP’s 2026 schedule explicitly permits additional doses based on shared clinical decision-making at least 2 months after the last dose. AAP lists a 2-month minimum for post-initial-series doses in immunocompromised adolescents, including mNexspike; CDC lists 3 months for mNexspike and allows case-by-case dosing outside its intervals. For immunocompetent adolescents receiving mNexspike, AAP specifies at least 12 weeks after the last dose; CDC specifies 3 months (although in either case, a dose of mNexspike administered at least 2 months after the most recent dose should be considered valid and not repeated). See https://doi.org/10.1542/peds.2026-079045, www.aap.org/ImmunizationSchedule, and www.cdc.gov/covid/hcp/vaccine-considerations/routine-guidance.html.

Last reviewed: October 18, 2026

ACOG recommends COVID-19 vaccination during pregnancy and permits vaccination in any trimester, emphasizing receipt as soon as a dose is due to protect maternal and infant health. ACOG also recommends vaccination for eligible postpartum and lactating patients.

CDC’s September 2026 clinical considerations recommend vaccination for all adults, but its pregnancy and breastfeeding section emphasizes product-specific data in FDA package inserts. Previous versions of CDC recommendations have emphasized the evidence for the safety and benefits of COVID-19 vaccination during pregnancy; however, changes made to the website since 2025 have resulted in this information being removed from CDC’s website. As a result, CDC’s guidance no longer echoes ACOG’s strong pregnancy-specific recommendation, although no evidence supports a change in previous conclusions on the safety and effectiveness of the vaccine during pregnancy. See www.acog.org/clinical-information/maternal-immunization-schedule and www.cdc.gov/covid/hcp/vaccine-considerations/special-situations-and-populations.html.

Last reviewed: October 18, 2026

As of October 13, 2026, the American Academy of Family Physicians (AAFP) and CDC agree on routine updated vaccination of adults and on two seasonal doses 6 months apart for adults age 65 years and older. AAFP’s guidance covers nonpregnant immunocompetent adults beginning at age 19 years and specifically recommends vaccination of healthcare personnel. CDC’s adult recommendation begins at age 18 years.

AAFP recommends offering the updated vaccine as soon as it is available. See AFP guidance at www.aafp.org/assets/image/upload/v1788277985/pdf_2026_through_2027_influenza_rsv_sars_covid_2_guidance.pdf and CDC recommendations at www.cdc.gov/covid/hcp/vaccine-considerations/routine-guidance.html

Last reviewed: October 18, 2026

IDSA strongly recommends age-appropriate vaccination for adults and children with compromised immunity, and recommends that household members and close contacts be up to date. CDC also recommends vaccination for people age 6 months and older with moderate or severe immunocompromise. IDSA and CDC recommend an initial vaccination series for people with moderate or severe immunocompromise. IDSA references the schedule originally approved by ACIP in 2023–24 and which was the basis for the dosing tables published on CDC’s website at: www.cdc.gov/covid/hcp/vaccine-considerations/immunocompromised.html.

IDSA emphasizes timing by disease and treatment. For example, IDSA suggests vaccination at least 2 weeks before solid-organ transplantation or at least 3 months afterward, and consideration of at least 3–6 months after B-cell-depleting treatment in relevant groups. IDSA supports vaccination during treatment when optimal timing is not feasible. CDC provides detailed dose schedules, generally advises vaccination at least 2 weeks before starting or resuming immunosuppression, and advises approximately 4 weeks before the next ongoing B-cell-depleting treatment. These approaches require coordination with the treating clinician.

For people who have completed the initial series, CDC specifies two seasonal doses (generally spaced 6 months apart). IDSA does not explicitly recommend a second dose but it notes that a second current season dose may extend protection. See IDSA guidance at www.idsociety.org/practice-guideline/Seasonal-RTI-Vaccinations-in-Immunocompromised-Patients/ and CDC guidance at www.cdc.gov/covid/hcp/vaccine-considerations/immunocompromised.html.

Last reviewed: October 18, 2026

A recommendation and an FDA-approved indication are different. FDA labeling regulates the marketing of a vaccine, but not the practice of medicine. Off-label vaccination recommendations made by CDC and medical societies are not rare and typically occur when available data outstrips the pace of regulatory changes (or when it is unlikely the manufacturer will go through the expense and process of changing the label). When a major medical society or CDC recommends off-label use, that is considered a standard of care and supports a clinician’s professional decision to follow that recommendation. Depending upon an individual state’s scope-of-practice regulations, pharmacists may or may not be able to independently administer vaccinations under off-label conditions without a prescription or a standing order signed by a prescribing healthcare professional.

FDA labeling limits use in age-eligible people younger than age 65 to those with at least one high-risk underlying condition. Vaccination without such a condition is off-label, although the range of underlying conditions that increase the risk of severe disease is extremely broad. Recommended multidose schedules, including the second seasonal dose for adults age 65 years and older, are also off-label.

Last reviewed: October 18, 2026

The American Academy of Pediatrics (AAP) recommends COVID-19 vaccination for all children age 6 through 23 months and for children age 2 through 18 years in specified risk groups. AAP also recommends offering vaccination to other children whose parent or guardian desires protection.

The American Academy of Family Physicians (AAFP) recommends updated vaccination for all nonpregnant immunocompetent adults age 19 years and older and healthcare personnel.

The American College of Obstetricians and Gynecologists (ACOG) recommends vaccination during pregnancy, including in any trimester.

The Infectious Diseases Society of America (IDSA) recommends age-appropriate vaccination for adults and children with compromised immunity.

CDC recommends vaccination for all adults age 18 years and older and children age 6 months through 17 years with moderate or severe immunocompromise. For other children, CDC recommends shared clinical decision-making. CDC’s schedule is available here: www.cdc.gov/covid/hcp/vaccine-considerations/routine-guidance.html.

AAP and CDC recommend an initial series for previously unvaccinated children age 6 through 23 months who are not moderately or severely immunocompromised; older immunocompetent children receive a single current-season dose when vaccinated. AAFP and CDC recommend a single current-season dose for immunocompetent adults younger than age 65 and two doses 6 months apart for adults age 65 years and older. CDC specifies minimum intervals of 2 months for Comirnaty, Spikevax, or Nuvaxovid and 3 months for mNexspike between the two seasonal doses.

People with moderate or severe immunocompromise follow a separate schedule that includes an initial vaccination series (CDC and IDSA agree on the initial vaccination series schedule). If the initial series has been completed in the past, CDC recommends two doses of current season COVID-19 vaccine 6 months apart (with a minimum interval of 3 months when using mFlusiva or 2 months for other products). IDSA recommends one dose and its guidance remarks that an additional current season dose may extend protection.

Additional details are provided in separate questions. See the medical society recommendations at the links below:

Last reviewed: October 18, 2026

People who are moderately or severely immunocompromised are at increased risk for severe COVID-19 illness. CDC recommends two current-season doses for those who completed an initial series before the current season. People who are unvaccinated or incompletely vaccinated need an initial series or its completion followed by a dose 6 months later. The number of doses and intervals depend on age, product, and vaccination history. Refer to detailed dosing tables at www.cdc.gov/covid/hcp/vaccine-considerations/immunocompromised.html.

IDSA strongly recommends administration of age-appropriate 2026–2027 COVID-19 vaccinations to all adults and children with compromised immunity and recommends that household members and close contacts be up to date with COVID-19 vaccination: www.idsociety.org/practice-guideline/Seasonal-RTI-Vaccinations-in-Immunocompromised-Patients/. However, IDSA does not explicitly recommend a second current-season dose for people who have previously completed an initial series. Instead, IDSA remarks that a second current season dose may extend protection. AAP aligns with CDC by recommending two or more current-season doses for children age 6 months through 18 years with moderate or severe immunocompromise and permits additional doses based on shared clinical decision-making: www.aap.org/ImmunizationSchedule.

Last reviewed: October 18, 2026

Before 2025, CDC recommended that all doses of COVID-19 vaccine given to children age 6 months through 4 years be from the same manufacturer. However, beginning with the 2025–26 season, only Moderna’s Spikevax mRNA vaccine has been licensed and recommended for use in children younger than age 5 years. AAP and CDC recommend that all children in this age group who are vaccinated against COVID-19 receive Spikevax, regardless of the brand they received in previous seasons. AAP and CDC recommend that if the child is age 6 months through 23 months and received an incomplete (1- or 2-dose) initial COVID-19 vaccination series with Pfizer-BioNTech, a 3-dose initial series should be completed with Spikevax. It is not necessary to start the initial series over.

In previously unvaccinated people age 5 years or older with moderate or severe immunocompromise, CDC recommends the same manufacturer for all initial COVID-19 vaccine series doses (either 2 doses of Nuvaxovid [if age 12 years or older] or 3 doses of an mRNA product). After completion of the initial series, any age-appropriate COVID-19 vaccine may be used in this age group.

CDC sets out conditions when it is acceptable to use an age-appropriate COVID-19 vaccine from a different manufacturer in any situation where CDC recommends the same manufacturer:

  • Same vaccine not available at the time of the clinic visit
  • Previous dose unknown
  • Person would otherwise not receive a recommended vaccine dose
  • Person starts but unable to complete a vaccination series with the same COVID-19 vaccine due to a contraindication
Last reviewed: October 18, 2026

AAP’s 2026 immunization schedule permits additional age-appropriate COVID-19 vaccine doses for moderately or severely immunocompromised children and adolescents based on shared clinical decision-making, at least 2 months after the most recent dose: www.aap.org/ImmunizationSchedule.

CDC recommends two 2026–2027 doses 6 months apart for people with moderate or severe immunocompromise who completed an initial series before the season (minimum interval 2 months for Comirnaty, Spikevax, and Nuvaxovid; 3 months for mNexspike). CDC does not specifically recommend additional doses, but advises clinicians to use vaccines off-label outside FDA and CDC dosing intervals on a case-by-case basis when benefits outweigh potential risks: www.cdc.gov/covid/hcp/vaccine-considerations/immunocompromised.html.

IDSA strongly recommends current-season vaccination and notes that a second current-season booster dose may extend protection. IDSA recommends individualizing timing around the patient’s condition and treatment: www.idsociety.org/practice-guideline/Seasonal-RTI-Vaccinations-in-Immunocompromised-Patients/.

Last reviewed: October 18, 2026

Janssen (Johnson & Johnson) COVID-19 vaccine is no longer produced. The last remaining doses expired May 7, 2023. The history of Janssen vaccine use is relevant only to evaluation of an adult with moderate or severe immunocompromise because such individuals are recommended to receive an initial series of COVID-19 vaccine. History of a single dose of Janssen COVID-19 vaccine constitutes a complete initial series. A person with this history should follow the vaccination schedule recommended for an immunocompromised person who has already completed an initial vaccination series.

Last reviewed: October 18, 2026

Yes. CDC recommends that vaccination be offered regardless of history of prior SARS-CoV-2 infection or long COVID.

Because COVID-19 illness temporarily boosts immunity, CDC states that people who have recently had SARS-CoV-2 infection may consider delaying a 2026–2027 COVID-19 vaccine dose by up to 3 months following symptom onset or positive COVID-19 test (if asymptomatic). Studies have shown that a longer time between infection and vaccination may improve the immune response to vaccination. The likelihood of reinfection in the first few months following infection is low.

A recipient’s individual risks for severe disease and current COVID-19 conditions in the community should be taken into account when deciding whether to delay vaccination up to 3 months after infection. As with all vaccines, vaccination should be deferred until after recovery from moderate to severe illness.

Last reviewed: October 18, 2026

Adults age 65 years and older have the highest rates of hospitalization and death from COVID-19 illness. Protection against severe COVID-19 disease wanes after a few months. Disease surveillance data from the United States shows that SARS-CoV-2 viruses circulate and cause illness at varying levels year-round, with waves of activity observed historically in winter and late summer. This pattern is not like influenza, which usually causes a single epidemic wave (sometimes with more than one peak) each winter.

The American Academy of Family Physicians (AAFP) and CDC recommend that adults age 65 years and older receive a second dose of any 2026–2027 COVID-19 vaccine 6 months after their first 2026–2027 COVID-19 vaccine dose (minimum interval of 2 months for Comirnaty, Spikevax, and Nuvaxovid; minimum interval of 3 months for mNexspike). The second dose does not have to be the same brand as the first. See CDC guidance at www.cdc.gov/covid/hcp/vaccine-considerations/routine-guidance.html and AAFP guidance at www.aafp.org/assets/image/upload/v1788277985/pdf_2026_through_2027_influenza_rsv_sars_covid_2_guidance.pdf.

Last reviewed: October 18, 2026

The minimum interval is 8 weeks if using Spikevax (Moderna), Comirnaty (Pfizer-BioNTech), or Nuvaxovid (Sanofi-Novavax), and 3 months if using mNexspike (Moderna). An early dose of mNexspike inadvertently administered at least 8 weeks after a previous dose does not need to be repeated.  

The exception to this standard interval is when the updated product dose is part of an initial vaccine series given to a young child or to a moderately or severely immunocompromised person. In those situations, simply continue with the series schedule using the updated product.  

Last reviewed: September 23, 2026

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 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.

COVID-19 vaccines were originally administered under EUA. All available 2026–2027 COVID-19 vaccines are fully licensed by FDA and no longer administered under EUA.

Last reviewed: October 18, 2026

AAP has developed one-page immunization fact sheets intended to supplement, but not replace, the CDC Vaccine Information Statements (VISs) for vaccines given to children. VISs are required by federal law to be provided for all vaccines covered by the National Vaccine Injury Compensation Program, which includes all vaccines routinely recommended for children or during pregnancy.  

The fact sheets, some of which are available in Spanish, can be downloaded at no cost from the AAP website at  www.aap.org/en/patient-care/immunizations/immunization-fact-sheets/.  

Last reviewed: September 23, 2026

The Pfizer-BioNTech COVID-19 Vaccine (Comirnaty) and the Moderna COVID-19 vaccines (Spikevax, mNexspike) are lipid nanoparticle-formulated, nucleoside-modified mRNA vaccines encoding the prefusion spike glycoprotein of SARS-CoV-2, the virus that causes COVID-19. The 2026–2027 mRNA vaccines target the Omicron JN.1-lineage XFG strain. Moderna’s mNexspike was first licensed in 2025 for ages 12 years and older. It is designed to reduce the amount of mRNA required to elicit the same or slightly better immune response compared to Spikevax (10 mcg of mRNA versus 50 mcg of mRNA for an adult dose). CDC states that Spikevax and mNexspike may be used interchangeably when both are age appropriate. Visit the Children’s Hospital of Philadelphia (CHOP) Vaccine Education Center website for more details, including short videos, about how mRNA vaccines work: www.chop.edu/vaccine-education-center/science-history/vaccine-science/how-are-vaccines-made#mrnavaccines.

Last reviewed: October 18, 2026

Spikevax and mNexspike are both mRNA vaccines targeting the same strain of COVID-19. Spikevax is the original vaccine now licensed down to age 6 months. The mNexspike product is a newer mRNA vaccine licensed for ages 12 years and older with an advanced design that achieves the same or slightly better immune response with less mRNA in each dose (10 mcg in mNexspike compared to 50 mcg in adult doses of Spikevax). CDC states that the two products may be used interchangeably when age appropriate.

For anyone recommended to receive a second dose 6 months after their first 2026–2027 dose (including all adults age 65 years and older), the minimum interval between the two recommended 2026–27 season doses is 3 months for mNexspike, but only 2 months for the other COVID-19 vaccine products. If mNexspike is inadvertently administered after only 2 months, the dose counts as valid and does not need to be repeated.

Last reviewed: October 18, 2026

They are only interchangeable for people age 12 years or older. Spikevax and mNexspike are both mRNA-based COVID-19 vaccines manufactured by Moderna. Spikevax is given as a 0.25 mL (25 mcg) dose for ages 6 months through 11 years and 0.5 mL (50 mcg) for ages 12 years and older. The mNexspike dose as 0.2 mL (10 mcg) for ages 12 years and older. Each of these three options is packaged as a manufacturer-filled syringe in the United States. It is important to verify the product name, age indication, and dose volume before every injection.

Last reviewed: October 18, 2026


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Last reviewed: January 9, 2026

It is estimated that for every million doses administered, about one (~0.0001%) will result in an anaphylactic reaction following vaccination. The estimate for mRNA COVID-19 vaccines is slightly higher, at approximately 5 anaphylactic reactions per million doses administered, according to CDC. With proper screening, most providers who administer thousands of vaccines in their lifetimes will never see an anaphylactic reaction.

Last reviewed: October 18, 2026

The original COVID-19 vaccines all targeted the spike protein of the original SARS-CoV-2 virus. The 2026–2027 formulation vaccines target the spike protein of the Omicron JN.1-lineage XFG strain for all four products. The update is intended to boost production of antibodies that protect more effectively against disease caused by currently circulating Omicron subvariants.

The process of updating the strain without changing anything else is similar to the seasonal strain changes made for influenza vaccinations each year. Vaccine safety, side effects, and risk of allergic reactions are expected to be comparable to earlier formulations of vaccines of the same brand and dose. As with seasonal influenza vaccines, future COVID-19 vaccines can continue to be updated when needed, as the circulating viruses evolve.

Last reviewed: October 18, 2026

No. The last U.S. doses of Janssen COVID-19 Vaccine expired May 7, 2023.

Last reviewed: October 18, 2026

Nuvaxovid is the brand name of the adjuvanted protein subunit COVID-19 vaccine developed by Novavax and commercialized by Sanofi beginning in the 2025–26 season. It contains the Omicron JN.1-lineage XFG variant SARS-CoV-2 spike protein and Matrix-M adjuvant. The saponin-based adjuvant is made from extracts of the bark of the Soapbark tree native to Chile. It is added to enhance the immune response of the vaccine recipient. The spike protein is produced in insect cells.

The 2026–2027 formulation of Nuvaxovid is FDA-licensed for people age 65 years and older and people age 12 through 64 years with at least one condition that increases the risk of severe COVID-19. For people who are not moderately or severely immunocompromised, CDC’s schedule calls for a single dose at ages 12 through 64 years, given at least 8 weeks after the most recent dose of COVID-19 vaccine, regardless of the recipient’s vaccination history. CDC recommends that immunocompetent people age 65 years or older, and immunocompromised people age 12 years and older who completed an initial series before this season, receive 2 doses of 2026–2027 COVID-19 vaccines, 6 months apart (with a minimum interval of 2 months between doses if using Nuvaxovid for both doses).

CDC and the Infectious Diseases Society of America (IDSA) recommends a 2-dose initial series for previously unvaccinated recipients who are moderately or severely immunocompromised, with the doses given at least 3 weeks apart. A third dose of any age-appropriate COVID-19 vaccine is recommended 6 months after the initial series is completed (with a minimum interval of 2 months between doses if using Nuvaxovid).

Last reviewed: October 18, 2026

The benefit of COVID-19 vaccination to an individual patient varies depending on the health status of the patient, their history of vaccination and COVID-19 infection, and the circulating COVID-19 strains. Observational studies show that updated vaccination provides additional protection against medically attended and severe COVID-19.

A CDC-led VISION study of immunocompetent adults age 18 years and older during September through December 2025 estimated effectiveness of 2025–2026 COVID-19 vaccination at 50% against COVID-19-associated emergency department or urgent care visits and 55% against hospitalization, compared with not receiving a 2025–2026 dose: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2850668.

CDC’s pediatric VISION report, published December 11, 2025, estimated effectiveness of 2024–2025 COVID-19 vaccination against emergency department or urgent care visits at 76% for immunocompetent children age 9 months through 4 years and 56% for those age 5 through 17 years during the first 7–179 days after vaccination: www.cdc.gov/mmwr/volumes/74/wr/mm7440a1.htm. These estimates describe the formulations in use at that time, not the 2026–2027 XFG formulation.

Last reviewed: October 18, 2026

FDA provides current package inserts for all four licensed COVID-19 vaccines: www.immunize.org/official-guidance/fda/pkg-inserts/. CDC summarizes products, age indications, and dosing at www.cdc.gov/covid/hcp/vaccine-considerations/overview.html. Immunize.org also provides links to vaccine resources and current guidance on its COVID-19 main page: www.immunize.org/vaccines/a-z/covid-19/.

Last reviewed: October 18, 2026

CDC recommends vaccination for children age 6 months through 17 years with moderate or severe immunocompromise. For all other children in this age group, CDC recommends shared clinical decision-making, emphasizing the greater benefit for children at increased risk of severe disease. CDC recommends vaccination for all adults beginning at age 18 years: www.cdc.gov/covid/hcp/vaccine-considerations/routine-guidance.html.

AAP’s 2026–27 recommendations cover children and adolescents through age 18 years. Refer to the full statement and the 2026 AAP immunization schedule: https://doi.org/10.1542/peds.2026-079045; www.aap.org/ImmunizationSchedule. In summary, AAP recommends age-appropriate COVID-19 vaccination of the following groups:

  • All children age 6 months through 23 months
  • Residents of long-term care facilities or other congregate settings
  • Children who have never been vaccinated against COVID-19
  • Infants and children with household contacts who are at high risk for severe COVID-19
  • All children who are at risk of severe COVID-19 due to underlying conditions or treatments, including: chronic pulmonary disease, cardiovascular disease, gastrointestinal disorders, hepatic disease, hematologic disease, metabolic disorders, obesity, neurologic and neurodevelopmental conditions, immunosuppressive conditions, and rheumatologic or autoimmune disease
  • Children age 2 through 18 years not in the above categories whose parent or guardian desires their protection from COVID-19
Last reviewed: October 18, 2026

AAP specifically recommends a single, age-appropriate, current-season dose for children age 2 through 18 years who have never been vaccinated, even without another risk condition. AAP also recommends vaccination for children in this age range with high-risk household contacts. Finally, AAP supports vaccination of any child whose parent or guardian wants them to be protected through vaccination. CDC recommends vaccination based on shared clinical decision-making between parent or guardian and healthcare provider for all children without moderate or severe immunocompromise. For additional details, see https://doi.org/10.1542/peds.2026-079045 and www.cdc.gov/covid/hcp/vaccine-considerations/routine-guidance.html.

Last reviewed: October 18, 2026

AAP recommends giving the updated vaccine as soon as it is available and the child is eligible, rather than waiting for a particular point in the season. AAP also supports vaccination later in the year for eligible children who missed fall vaccination because SARS-CoV-2 circulates year-round. COVID-19 and influenza vaccines may be coadministered. It is acceptable to delay vaccination for up to 3 months following a confirmed COVID-19 infection, due to the reduced risk of infection in the weeks following an infection and evidence of a better response to vaccination if spaced longer after an infection. Individual risk and local epidemiology may also affect timing decisions. See https://doi.org/10.1542/peds.2026-079045.

Last reviewed: October 18, 2026

AAP recommends that this child receive one dose recommended for his age at the time of the vaccination visit. At age 11 years, an age-appropriate single dose of either Comirnaty (Pfizer-BioNTech) or Spikevax (Moderna) mRNA vaccine is recommended. If the patient arrives in your clinic after turning 12 years old, the 2026–2027 Nuvaxovid (Sanofi-Novavax) protein subunit vaccine and the mNexspike (Moderna) mRNA vaccine are also options. These single-dose recommendations apply if he is not moderately or severely immunocompromised.

Last reviewed: October 18, 2026

CDC recommends that moderately or severely immunocompromised children who transition from age 11 years to age 12 years during the initial vaccination series complete the 3-dose series using the dosage for people ages 12 years and older for all doses received once they are age 12 years.

See www.cdc.gov/covid/hcp/vaccine-considerations/immunocompromised.html for additional details.

Last reviewed: October 18, 2026

Both vaccines have been demonstrated to be safe, with side effects typical of those in older age groups. The most common local reaction in this age group is pain at the injection site; the most common systemic symptom in older children was fatigue and in younger children (6 through 23 months) irritability/crying and sleepiness were most common. Fever may occur after either vaccination. Febrile seizures can occur in infants and young children ages 6 months through 5 years as a result of any condition that causes a fever (most common with high fevers). Febrile seizures are uncommon after vaccination. Febrile seizures were rare after mRNA COVID-19 vaccine clinical trials in this age group, and CDC continues to monitor for this adverse event following vaccination in infants and young children.

No cases of myocarditis were reported during the clinical trials for either vaccine. To date, post-authorization surveillance has not detected an increased risk for myocarditis and pericarditis following mRNA COVID-19 vaccination in children ages 6 months–4 years (Pfizer-BioNTech) and ages 6 months–5 years (Moderna).

Last reviewed: October 18, 2026


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Last reviewed: June 22, 2023

Comirnaty (Pfizer-BioNTech) mRNA COVID-19 vaccine is FDA-licensed for use in ages 5 years through 64 years with at least one underlying condition that puts them at risk for severe COVID-19 infection and individuals 65 years and older.

mNexspike (Moderna) is FDA-licensed for use in ages 12 through 64 years with at least one underlying condition that puts them at risk for severe COVID-19 infection and individuals 65 years and older.

Nuvaxovid (Sanofi-Novavax) is FDA-licensed for use in ages 12 through 64 years with at least one underlying condition that puts them at risk for severe COVID-19 infection and individuals 65 years and older.

Spikevax (Moderna) mRNA COVID-19 vaccine is FDA-licensed for use in ages 6 months through 64 years with at least one underlying condition that puts them at risk for severe COVID-19 infection and individuals 65 years and older.

Recommendations of CDC and major medical societies for use of these products are broader than the narrow FDA-licensed indications, as described in other answers.

Last reviewed: October 18, 2026

Clinical trial results for the original monovalent Pfizer-BioNTech COVID-19 Vaccine (administered as a two-dose primary series) demonstrated that 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.

The safety and side effects of the 2026–2027 formulations are expected to be consistent with the previous formulations of the product.

Last reviewed: October 18, 2026

The 2026–2027 Nuvaxovid (Sanofi-Novavax) vaccine is an option for any person age 12 years or older who is due for a 2026–2027 updated vaccination. CDC provides the following 2026–27 season dosing schedules (if using Nuvaxovid for all doses) for different ages and health conditions:

  • Age 12 through 64 years, not moderately or severely immunocompromised: one 2026–2027 dose, at least 8 weeks after most recent dose from a previous season
  • Age 65 years and older, not moderately or severely immunocompromised: two 2026–2027 doses 6 months apart (minimum interval 2 months)
  • Age 12 years or older, moderately or severely immunocompromised:
    • Previously unvaccinated: give 2 doses at least 3 weeks apart as an initial series, followed by a third dose about 6 months after dose 2 (minimum interval 2 months)
    • Previously completed an initial series of any COVID-19 vaccine (2 doses of Novavax protein subunit vaccine or 3 doses of an mRNA vaccine): give first 2026–2027 dose at least 8 weeks after most recent COVID-19 vaccine from the previous season, then give a second dose about 6 months later (minimum interval, 2 months)

For dosing details, see CDC’s schedule at www.cdc.gov/covid/hcp/vaccine-considerations/immunocompromised.html and, for children and adolescents, AAP’s schedule at www.aap.org/ImmunizationSchedule. The Infectious Diseases Society of America (IDSA) endorses the CDC’s initial vaccination series for people with moderate or severe immunocompromise, though it does not routinely recommend a second dose during the season for those who have already had an initial series (it merely states that a second dose may extend protection). Immunize.org’s current standing orders templates cover all vaccine types in separate pediatric and adult documents: www.immunize.org/wp-content/uploads/catg.d/p3140a.pdf and www.immunize.org/wp-content/uploads/catg.d/p3140.pdf.

Last reviewed: October 18, 2026

Yes. Evidence continues to demonstrate that COVID-19 vaccination is safe and effective during any stage of pregnancy; the benefits of vaccination clearly outweigh any known or potential risks of COVID-19 vaccination during pregnancy. The currently licensed COVID-19 vaccines are nonreplicating vaccines and cannot cause infection in either the mother or the fetus. No evidence exists of risk to the fetus from vaccinating during pregnancy with nonreplicating vaccines in general.

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 related to vaccination during pregnancy for mother or infant.

Pregnant women have historically been at an increased risk of severe disease, adverse pregnancy outcomes, and maternal death from COVID-19 infections.

The American College of Obstetricians and Gynecologists (ACOG) recommends all pregnant women receive any age-appropriate 2026–2027 COVID-19 vaccine if they are due for vaccination; ACOG recommends vaccination in any trimester as soon as possible to protect maternal and infant health. Current ACOG recommendations are available here: www.acog.org/clinical/clinical-guidance/practice-advisory/articles/2020/12/covid-19-vaccination-considerations-for-obstetric-gynecologic-care. ACOG’s 2026 maternal schedule is available at www.acog.org/clinical-information/maternal-immunization-schedule.

Last reviewed: October 18, 2026

Pregnant women have historically been at an increased risk of severe disease, adverse pregnancy outcomes, and maternal death from COVID-19 infections. Studies have shown that antibodies produced after COVID-19 vaccination during pregnancy are transferred to the newborn, and COVID-19 vaccination during pregnancy reduces the risk of COVID-19 hospitalization in infants younger than 6 months.

CDC’s September 2026 clinical considerations have removed text documenting the safety and benefits of COVID-19 vaccination during pregnancy; however, CDC continues to routinely recommend COVID-19 vaccination for all adults, including during pregnancy, and pregnancy is a high-risk condition for severe COVID-19.

The American College of Obstetricians and Gynecologists (ACOG) routinely recommends all pregnant women receive any age-appropriate 2026–2027 COVID-19 vaccine if they have not already received one. ACOG recommends vaccination in any trimester as soon as possible when a dose is due. ACOG’s guidance does not call for an extra dose solely because a person becomes pregnant after receiving the current-season dose. Current ACOG recommendations are available here: www.acog.org/clinical/clinical-guidance/practice-advisory/articles/2020/12/covid-19-vaccination-considerations-for-obstetric-gynecologic-care. ACOG’s 2026 maternal schedule is available at www.acog.org/clinical-information/maternal-immunization-schedule.

Last reviewed: October 18, 2026


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Last reviewed: January 9, 2026

Yes. The American College of Obstetricians and Gynecologists (ACOG) recommends COVID-19 vaccination for eligible lactating and postpartum patients. Breastfeeding does not need to be interrupted for vaccination. See www.acog.org/clinical-information/maternal-immunization-schedule.

Last reviewed: October 18, 2026

IDSA strongly recommends age-appropriate 2026–2027 COVID-19 vaccination for immunocompromised adults and children, with timing tailored to the condition and treatment. Details of timing considerations are provided in Table 1 of the IDSA recommendations at: www.idsociety.org/practice-guideline/Seasonal-RTI-Vaccinations-in-Immunocompromised-Patients/. For children and adolescents through age 18 years, use AAP’s 2026 immunization schedule: www.aap.org/ImmunizationSchedule. CDC provides detailed schedule tables here: www.cdc.gov/covid/hcp/vaccine-considerations/immunocompromised.html.

Immunize.org also provides current COVID-19 vaccination resources and standing orders templates on its main page: www.immunize.org/vaccines/a-z/covid-19/. The following links provide standing orders templates:

Due to the timing and clinical considerations outlined by IDSA, the standing orders templates refer moderately or severely immunocompromised patients for individual clinical evaluation rather than providing their complete dosing schedule. Use the AAP or CDC schedules linked above for dosing schedules.

CDC recommends that people who are moderately or severely immunocompromised and previously unvaccinated receive a 2-dose (protein subunit) or 3-dose (mRNA) initial series of COVID-19 vaccine, with an additional dose 6 months later of any age-appropriate COVID-19 brand (minimum interval of 2 months for Nuvaxovid, Spikevax, or Comirnaty; 3-month minimum interval for mNexspike). CDC recommends use of the same manufacturer for all doses of the initial series when feasible. Spikevax and mNexspike are both made by Moderna and are interchangeable in ages 12 years and older. These recommendations were originally made in the 2023–24 season and are endorsed by IDSA.

CDC recommends that those who completed an initial series before the 2026–2027 vaccines were available receive 2 doses of 2026–2027 COVID-19 vaccine (any age-appropriate brand) about 6 months apart (minimum interval of 2 months for Nuvaxovid, Spikevax, or Comirnaty; 3-month minimum interval for mNexspike).

IDSA recommends a single dose of current season vaccine and remarks that a second dose 6 months later may extend protection, but it does not routinely recommend a second dose.

AAP’s 2026 schedule permits additional doses for moderately or severely immunocompromised children and adolescents based on shared clinical decision-making, at least 2 months after the most recent dose. For ages 12 through 18 years, AAP lists a 2-month minimum interval for the post-initial-series dose, including either Moderna product; CDC specifically recommends a 3-month interval when using mNexspike.

Last reviewed: October 18, 2026

The conditions and treatments that CDC specifies may result in moderate or severe immunocompromise include but are not limited to:

  • Active treatment for solid tumor and hematologic malignancies
  • Hematologic malignancies associated with poor responses to COVID-19 vaccines regardless of current treatment status (e.g., chronic lymphocytic leukemia, non-Hodgkin lymphoma, multiple myeloma, acute leukemia)
  • Receipt of solid-organ transplant or an islet transplant and taking immunosuppressive therapy
  • Receipt of chimeric antigen receptor (CAR)-T-cell therapy or hematopoietic cell transplant (HCT) (within 2 years of transplantation or taking immunosuppressive therapy)
  • Moderate or severe primary immunodeficiency (e.g., common variable immunodeficiency disease, severe combined immunodeficiency, DiGeorge syndrome, Wiskott-Aldrich syndrome)
  • Advanced HIV infection (people with HIV and CD4 cell counts less than 200/mm³, history of an AIDS-defining illness without immune reconstitution, or clinical manifestations of symptomatic HIV) or untreated HIV infection
  • Active treatment with high-dose corticosteroids (i.e., 20 mg or more of prednisone or equivalent per day when administered for 2 or more weeks), 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 (e.g., B-cell-depleting agents)

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. CDC recommends deferring to the patient’s clinical care team to evaluate the degree of immunocompromise and timing of vaccination.

See CDC’s interim clinical considerations for this population: www.cdc.gov/covid/hcp/vaccine-considerations/immunocompromised.html.

IDSA did not change the definition of conditions considered moderately or severely immunocompromising when it issued its 2026 guidance. See Infectious Diseases Society of America (IDSA) recommendations for the immunocompromised at:  www.idsociety.org/practice-guideline/Seasonal-RTI-Vaccinations-in-Immunocompromised-Patients/.

Last reviewed: October 18, 2026

Yes. See revaccination considerations at www.cdc.gov/covid/hcp/vaccine-considerations/immunocompromised.html. This is the most current statement from CDC on COVID-19 revaccination:

Recipients of chimeric antigen receptor (CAR)-T-cell therapy or hematopoietic cell transplant (HCT) who received 1 or more doses of COVID-19 vaccine prior to or during treatment should be revaccinated. Revaccination should start at least 3 months (12 weeks) after transplant or CAR-T-cell therapy and should follow the currently recommended schedule for people who are unvaccinated.

Revaccination may also be considered for patients who received 1 or more doses of COVID-19 vaccine during treatment with B-cell-depleting therapies (e.g., rituximab, ocrelizumab) that were administered over a limited period (e.g., as part of a treatment regimen for certain malignancies) according to the currently recommended schedule for people who are unvaccinated. The suggested interval to start revaccination is about 6 months after completion of the B-cell-depleting therapy. Timing of vaccination for patients who receive B-cell-depleting therapies on a continuing basis (e.g., for treatment of certain autoimmune conditions such as rheumatoid arthritis or multiple sclerosis) is addressed in CDC’s considerations for timing of COVID-19 vaccination in relation to immunosuppressive therapies.

CDC continues to recommend that a patient’s clinical team is best positioned to determine the degree of immune compromise, need for revaccination, and appropriate timing of revaccination.

The Infectious Diseases Society of America (IDSA) also addresses people with immunocompromise, including revaccination, in its guidance: www.idsociety.org/practice-guideline/Seasonal-RTI-Vaccinations-in-Immunocompromised-Patients/.

Last reviewed: October 18, 2026

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. For patients who receive B-cell-depleting therapies on a continuing basis, COVID-19 vaccines should be administered approximately 4 weeks before the next scheduled therapy.

CDC also notes that timing of COVID-19 vaccination should take into consideration current or planned immunosuppressive therapies, optimization of both the patient’s medical condition and response to vaccination, and individual benefits and risks. CDC’s considerations for COVID-19 vaccination of those on immunosuppressive therapies here: www.cdc.gov/covid/hcp/vaccine-considerations/immunocompromised.html

CDC states that on a case-by-case basis, providers caring for these patients may administer COVID-19 vaccines outside of the FDA and CDC dosing schedules based on their clinical judgment of what is most beneficial to the patient.

The Infectious Diseases Society of America (IDSA) 2026 guidance provides condition-specific timing, including consideration of vaccination at least 3–6 months after the last B-cell-depleting infusion. IDSA allows for vaccination during treatment when optimal timing is not feasible, and notes that the immune response may be reduced. IDSA recommends coordinating timing decisions with the treating specialist: www.idsociety.org/practice-guideline/Seasonal-RTI-Vaccinations-in-Immunocompromised-Patients/.

Last reviewed: October 18, 2026

CDC and medical societies all agree that people may self-attest to a high-risk condition, including moderate or severe immunocompromise and should not be denied vaccination because they lack documentation.

Last reviewed: October 18, 2026


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Last reviewed: January 9, 2026

CDC recommends that immunocompromised people who need an initial series of 3 doses of mRNA COVID-19 vaccine or two doses of Nuvaxovid (Sanofi-Novavax) adjuvanted protein COVID-19 vaccine receive the initial series using COVID-19 vaccines from the same manufacturer, unless it is not feasible. If the same manufacturer cannot be used for all primary series doses (e.g., the brand is unavailable at the time of the vaccination visit, the previous brand is unknown, or the patient would not be vaccinated with the previous brand due to a contraindication or other reason), then administer another age-appropriate brand.

Spikevax (Moderna) is the only licensed 2026–2027 COVID-19 vaccine option for children younger than age 5 years. If the immunocompromised recipient is age 5 years or older, once the initial series is complete, any appropriate brand may be used for all subsequent doses. Spikevax and mNexspike are interchangeable when age-appropriate: both vaccines are made by Moderna.

Last reviewed: October 18, 2026

Under CDC’s guidance, the patient’s initial series is considered complete following a single dose of the Janssen COVID-19 Vaccine. People who are moderately or severely immunocompromised and have completed an initial series (no matter how long ago) should now receive 1 dose of an age-appropriate 2026–2027 COVID-19 vaccine (at least 8 weeks after their most recent dose of a previous formulation for Comirnaty, Spikevax, or Nuvaxovid; at least 3 months for mNexspike). CDC routinely recommends they receive a second 2026–2027 COVID-19 vaccine dose 6 months later (minimum interval 2 months for Comirnaty, Spikevax, and Nuvaxovid; minimum interval of 3 months if using mNexspike). Infectious Diseases Society of America (IDSA) simply remarks that a second current-season dose may extend protection.

Last reviewed: October 18, 2026

CDC recommends (and IDSA concurs with this schedule) that the patient receive a 2026–2027 COVID-19 mRNA dose now, of the same manufacturer as the initial two doses (if feasible), in order to complete the 3-dose initial mRNA vaccine series recommended for people with moderate or severe immunocompromise. Advise the patient that he should receive an additional 2026–2027 COVID-19 dose of any brand in 6 months (minimum interval 2 months if using Comirnaty, Spikevax, or Nuvaxovid; minimum interval 3 months if using mNexspike).

Last reviewed: October 18, 2026

All COVID-19 vaccines are administered intramuscularly. The 2026–2027 products are only available in the United States in manufacturer-filled syringes, with the exception of single-dose vials of Comirnaty (Pfizer-BioNTech) formulation for children age 5 through 11 years.

Last reviewed: October 18, 2026

Yes. CDC 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/covid/hcp/vaccine-considerations/appendices.html.

Categories of errors covered in the CDC table include:

  • Site/route
  • Age
  • Product and dosage
  • Storage and handling
  • Incorrect intervals
  • Interchanging product types when not recommended

When an error occurs, the patient should be informed of the error, the clinical staff should evaluate why the error occurred, and should implement strategies to prevent future errors. CDC encourages reporting administration errors to VAERS (https://vaers.hhs.gov), whether or not an adverse event occurred. Follow error-specific guidance on whether and when to repeat the dose.

Last reviewed: October 18, 2026

If exactly half the required volume was given, CDC allows the other half to be administered on the same clinic day and the two injections to count as one dose. If the error cannot be corrected on the same clinic day, a full repeat dose should be given as soon as feasible. CDC’s error guidance also allows consideration of an 8-week interval before a repeat dose for people age 6 months through 64 years who are not moderately or severely immunocompromised, to potentially reduce the rare myocarditis risk. For guidance on a range of dosing errors, refer to CDC at www.cdc.gov/covid/hcp/vaccine-considerations/appendices.html.

Last reviewed: October 18, 2026

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). In the case of a subcutaneous injection, the patient should be advised of the possibility of self-limited local or systemic side effects.

Last reviewed: October 18, 2026

Providing a vaccine recipient with a COVID-19 vaccine VIS is recommended by CDC but not required. The requirement to provide the VIS to a patient is present only when a vaccine is included in the federal Vaccine Injury Compensation Program (VICP). COVID-19 vaccines are not included in the VICP at this time. The current official VIS and all available translations are available from Immunize.org: www.immunize.org/vaccines/vis/covid-19/.

Last reviewed: October 18, 2026


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Last reviewed: January 9, 2026

Periodically verify whether you are using the most current available 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. This resource is updated as needed with the dates of the most currently available materials from CDC, FDA, and major medical societies.

Last reviewed: October 18, 2026

No. CDC recommends administering the next dose that is currently recommended, using a vaccine from the same manufacturer, if feasible, even if previous doses in the series were an earlier formulation.

Last reviewed: October 18, 2026

CDC guidance allows for doses given up to 4 days before the recommended interval to be counted as valid – such doses do not need to be repeated. However, CDC advises that people should not be routinely scheduled to receive a dose earlier than recommended. Schedulers should offer appointments beginning on the date of the recommended interval or later.

Last reviewed: October 18, 2026

The Infectious Diseases Society of America (IDSA) published 2026 recommendations for the use of influenza, RSV, and COVID-19 vaccines in people with immunocompromise (see www.idsociety.org/practice-guideline/Seasonal-RTI-Vaccinations-in-Immunocompromised-Patients/). Its timing considerations align with AAP recommendations for timing of influenza vaccination of children with immunocompromise. A table with timing considerations is available at www.idsociety.org/globalassets/idsa/practice-guidelines/vaccine-gl/table-3-2026..pdf

Last reviewed: October 11, 2026

For the 2026–2027 season, only a single dose of 2026–2027 Nuvaxovid adjuvanted protein COVID-19 vaccine is recommended for recipients age 12 through 64 years who are not moderately or severely immunocompromised, regardless of their vaccination history. The American Academy of Family Physicians (AAFP) and CDC recommend that those age 65 years or older receive a second dose of any 2026–2027 COVID-19 vaccine 6 months after the first 2026–2027 dose (minimum interval 2 months if using Comirnaty, Spikevax, or Nuvaxovid; minimum interval 3 months if using mNexspike).

Last reviewed: October 18, 2026

An asymptomatic person who is scheduled for COVID-19 vaccination and is exposed to SARS-CoV-2 virus may be vaccinated. COVID-19 vaccination after an exposure is not useful as post-exposure prophylaxis, so vaccination should not be expected to prevent illness caused by past exposure. CDC and medical societies recommend deferring vaccination during moderate or severe acute illness until it improves. A person who is currently infectious should avoid exposing others at a vaccination visit. Healthcare facilities may have specific policies in place to reduce the risk of spread of respiratory viruses to healthcare staff and other patients.

People who recently had SARS-CoV-2 infection and are due for a COVID-19 vaccine may consider delaying the dose by up to 3 months from symptom onset or positive test (if infection was asymptomatic). According to CDC, increasing the time between infection and vaccination may result in an improved immune response to vaccination. There is a low risk of reinfection in the weeks following an infection. A recipient’s individual risks for severe disease and current COVID-19 conditions in the community should be taken into consideration when deciding whether to delay vaccination up to 3 months after infection.

Last reviewed: October 18, 2026

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