Issue 1,607: December 14, 2021
Ask the Experts: IAC Answers Questions about
COVID-19 Vaccination
As an additional service to IAC Express readers, we periodically publish special editions such as this one, providing you with new and updated Ask the Experts questions and answers from IAC experts. This issue includes 13 Q&As about COVID-19 vaccination based on recently updated ACIP recommendations.

To find the full set of IAC’s Ask the Experts COVID-19 vaccination Q&As, visit www.immunize.org/askexperts/experts_cov.asp

You can find all of these questions and answers, plus more than a thousand others about vaccines and vaccine administration, on our "Ask the Experts" gateway page at www.immunize.org/askexperts.
 
IAC's team of experts includes Kelly L. Moore, MD, MPH (team lead), Carolyn B. Bridges, MD, FACP, and Iyabode Beysolow, MD, MPH.

COVID-19 Vaccination Questions
COVID-19 Vaccination Questions
Q: Who is eligible to receive a booster dose of a COVID-19 vaccine?

A: As of December 9, 2021, all people who have completed primary vaccination against COVID-19 and are age 16 years or older are eligible to receive a COVID-19 vaccine booster dose at the appropriate interval. CDC recommends that all people age 18 years and older should receive a booster dose of COVID-19 vaccine, even if they were younger than age 18 years at the time of the primary series. People who are age 16 or 17 years also may receive a booster dose, based on individual benefits and risks. Currently, CDC does not recommend a booster dose in children younger than age 16 years, regardless of other characteristics or medical conditions. As more data from studies on long term protection become available, these recommendations may be updated. 
 
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 (Pfizer-BioNTech, Moderna, or Janssen) at least 2 months (8 weeks) after the Janssen COVID-19 single dose primary series.
 
People age 18 years and older who received an mRNA primary series should receive a single COVID-19 vaccine booster dose (Pfizer-BioNTech, Moderna, or Janssen) at least 6 months after completion of the primary series. At this time, only the Pfizer-BioNTech COVID-19 Vaccine can be used for booster vaccination for any person age 16 or 17 years.
 
For additional details, review the booster dose information available at CDC’s web page, “Interim Clinical Considerations for Use of COVID-19 Vaccines Currently Approved or Authorized in the United States”: www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19-vaccines-us.html.

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Q: What is the difference between an “additional primary dose” of COVID-19 vaccine recommended for an immunocompromised person and a “booster dose”?

A: An additional primary dose of mRNA vaccine after the standard 2-dose primary series of mRNA vaccine is recommended by CDC for people age 12 years or older with moderate or severe immunocompromise. In these populations, the immune response following the primary 2-dose series is likely to be insufficient, and the third primary dose increases the likelihood of developing a sufficient immune response. The additional primary dose of mRNA vaccine should not be delayed but is recommended to be the same brand and dose size as the original primary series doses. It may be given 28 days or more after the second dose of the primary series.
 
The term “booster dose” applies to an additional dose of vaccine administered only after the initial sufficient immune response to the primary series is likely to have waned over time. Booster doses are currently recommended only for individuals age 16 years or older. The interval between a primary series and a booster dose varies by vaccine type and the brand of the booster dose does not need to match the primary series if more than one brand is licensed or authorized for the recipient’s age. The recommended booster dose of Moderna COVID-19 Vaccine is half of a primary series dose (50 mcg instead of 100 mcg). Immunocompromised individuals age 16 years or older who have received an additional primary dose should receive an age-appropriate booster dose at least 6 months after the additional primary dose.
 
For details about vaccination of immunocompromised people, see the section on special populations or CDC’s interim clinical considerations for the use of COVID-19 vaccines: www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19-vaccines-us.html#considerations-covid19-vax-immunocopromised.

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Q: My patient, age 30, has moderate immunocompromise and received an additional primary dose as recommended. Is a booster dose also recommended?

A: Yes. CDC recommends that people age 12 years or older with moderate or severe immunocompromise who receive an mRNA COVID-19 vaccine 2-dose primary series should receive an additional primary dose at least 28 days after their second dose. If using Moderna vaccine, a full 100 mcg (0.5 mL) dose should be given as the additional primary dose.
 
People who receive an additional primary dose and are age 16 years or older also should receive a booster dose at least 6 months after receiving the additional primary (3rd) dose, for a total of four doses.
 
The booster (4th) dose may be any age-appropriate authorized or licensed COVID-19 vaccine. If using Moderna vaccine, administer a 50 mcg (0.25 mL) booster dose.

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Q: 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?

A: Additional primary doses are not currently recommended for immunocompromised recipients of a primary dose of Janssen vaccine. However, all recipients of Janssen vaccine, which is authorized for use only in people age 18 years or older, are recommended to receive a booster dose of any COVID-19 vaccine at least 8 weeks after their primary Janssen vaccine dose. Therefore, a person with moderate or severe immunocompromise who receives a primary Janssen vaccine dose should receive a booster dose of any COVID-19 vaccine at least 8 weeks after their primary dose. If Moderna vaccine is used, the standard 50 mcg (0.25 mL) booster dose should be administered.

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Q: 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 over 6 months since his second mRNA dose. What do I do now?

A: The patient should receive his additional primary dose now, using the same brand as the first two doses. If the primary series is Moderna, a full 100 mcg (0.5 mL) additional primary dose should be used.
 
The patient should be counseled to return 6 months after the additional primary dose for a booster dose of any authorized or licensed COVID-19 vaccine. If Moderna is used for the booster dose at that time, administer a 50 mcg (0.25 mL) booster dose. Booster doses are currently recommended only for people age 16 years and older.

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Q: What are the differences in the orange cap and purple cap formulations of Pfizer-BioNTech COVID-19 Vaccine?

A: The purple cap formulation of Pfizer-BioNTech COVID-19 Vaccine for age 12 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 orange cap 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 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 original (purple cap) formulation, 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.
 
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.

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Q: What are the recommendations for COVID-19 vaccination of children younger than 12 years?

A: 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 formulation of Pfizer-BioNTech COVID-19 Vaccine, administered 21 days apart.

Children in this age group with moderate or severe immunocompromise are not recommended to receive an additional primary dose at this time. Booster doses administered at least 6 months after the primary series are not recommended for this age group at this time.

The full ACIP recommendation is available here: www.cdc.gov/mmwr/volumes/70/wr/pdfs/mm7045e1-H.pdf.

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Q: 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?

A: No. Children 5 through 11 years should only be vaccinated with a 10 mcg dose (0.2 mL) of the orange cap 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. The CDC vaccine dosing chart comparing purple cap and orange cap Pfizer-BioNTech COVID-19 Vaccine formulations is here: www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/downloads/Pfizer-Dosage-Chart.pdf.
 
A properly diluted purple cap formulation for adolescents and adults delivers a 30 mcg dose in a 0.3 mL volume. Ten micrograms would be just 0.1 mL, a volume too small to reliably deliver the correct amount intramuscularly. It is never acceptable to alter the required dilution volume for the purple cap vial in order to create a larger dose volume.

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Q: 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 cap Pfizer-BioNTech vaccine formulation for adolescents and adults?

A: 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 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 cap doses, or any combination of orange cap and purple cap: in any of these circumstances the child is considered fully vaccinated. This is not considered an error and VAERS reporting is not indicated.

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Q: What do we know about the orange cap Pfizer-BioNTech COVID-19 Vaccine effectiveness and side effects in children age 5 through 11 years?  

A: Preliminary clinical trial results (initial enrollment of 2,268 children) showed that two 10-microgram (mcg) doses of orange cap 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.

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Q: We have a patient who was partially vaccinated with a COVID-19 vaccine not authorized for use in the United States. What should we do?

A: People who received only the first dose of a COVID-19 vaccine brand not authorized or licensed in the United States should be offered a complete primary series with an FDA-authorized or licensed COVID-19 vaccine. The minimum interval between the last dose of a non-FDA-authorized vaccine and an authorized or licensed COVID-19 vaccine is 28 days. After completion of primary vaccination with an FDA-authorized or licensed COVID-19 vaccine, these individuals are considered fully vaccinated, and are not recommended to receive an additional primary or booster dose at this time.

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 Q: We have a patient who was fully vaccinated outside the United States with a vaccine not authorized by FDA and not on the WHO emergency use list (WHO-EUL). What do we do?

A: People in the United States who received a complete series of a vaccine not listed for emergency use by the WHO should be offered a complete primary series with an FDA-authorized or licensed COVID-19 vaccine, beginning at least 28 days after their last non-FDA-authorized or licensed vaccine. After completion of primary vaccination with an authorized or licensed vaccine, these individuals are considered fully vaccinated and are not recommended to receive an additional primary or booster dose at this time.

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Q: What are CDC’s COVID-19 Vaccine Emergency Use Instructions (EUI) and to whom do they apply?

A: CDC has issued emergency use instructions (EUI) for the use of the FDA-licensed purple cap adolescent/adult Pfizer-BioNTech COVID-19 Vaccine (Comirnaty) that differ from the FDA-approved package insert. These instructions apply to certain people who completed primary series COVID-19 vaccination with vaccines not authorized or approved by the FDA as a part of a clinical trial or as a routine vaccination outside the United States.
 
The CDC EUI provides guidance that moderately and severely immunocompromised persons age 12 years or older who completed a primary series of WHO-EUL COVID-19 vaccines that are not FDA authorized or approved are eligible to receive a single additional primary series dose of the purple cap adolescent/adult formulation of Pfizer-BioNTech COVID-19 Vaccine at least 28 days after the most recent primary series dose.

The CDC EUI currently provides guidance that people age 16 years or older who have completed a primary series of WHO-EUL COVID-19 vaccines that are not FDA authorized or approved are eligible to receive a single booster dose of the purple cap adolescent/adult formulation of Pfizer-BioNTech COVID-19 Vaccine at least 6 months after the most recent primary series dose. 
 
People who receive a dose of Pfizer-BioNTech COVID-19 Vaccine in accordance with the CDC EUI should be provided a copy of a specifically-written EUI Fact Sheet for Recipients and Caregivers, available from CDC here: www.cdc.gov/vaccines/covid-19/eui/downloads/EUI-Caregiver.pdf.
 
CDC EUI resources, including the EUI fact sheet for providers and the EUI fact sheet for recipients and caregivers, are available here: www.cdc.gov/vaccines/covid-19/eui/index.html.

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Editorial Information

  • Editor-in-Chief
    Kelly L. Moore, MD, MPH
  • Managing Editor
    John D. Grabenstein, RPh, PhD
  • Associate Editor
    Sharon G. Humiston, MD, MPH
  • Writer/Publication Coordinator
    Taryn Chapman, MS
    Courtnay Londo, MA
  • Style and Copy Editor
    Marian Deegan, JD
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    Laurel H. Wood, MPA
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    Kayla Ohlde

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