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Frequently Asked Questions about the COVID-19 Vaccine


COVID-19 Vaccine for Children

  1. Is the Pfizer COVID-19 vaccine safe for children 5-11 years of age?
    The vaccine’s safety was studied in a clinical trial for children ages 5 through 11 and to date no serious side effects have been reported in those who received the vaccine. Also real world data collected since starting administration of vaccine in this age group have had no safety concern to date.

  2. Is the Pfizer COVID-19 vaccine effective in children 5-11 years of age?
    The vaccine appears to be as effective at preventing symptomatic COVID-19 infection as in adults.

  3. What are some common side effects in children after receiving a COVID-19 vaccine?
    Side effects were generally mild to moderate in severity. Most common are pain at injection site, fatigue, fever and headache. These are similar to the ones observed in those 12 years of age and older, occurred within two days after vaccination and resolved within one to two days.

  4. Are children eligible for COVID-19 vaccine boosters?
    Booster doses are permitted for people 12 years and older.

  5. Are children aged 5-11 who are immunocompromised eligible for a third dose?
    Third dose of Pfizer COVID 19 vaccine are now authorized and recommended in children who are moderately to severely immunocompromised.

  6. Why was a Pfizer COVID-19 vaccine third dose recommended for children 5-11 years of age who are moderately to severely immunocompromised?
    Children 5 through 11 years of age who are moderately to severely immunocompromised may not respond adequately to the two-dose primary vaccination series. To date, the FDA and CDC have seen no new safety signals with primary series in this age group. Thus, a third primary series dose has now been authorized for this vulnerable population. This will now allow these children to receive the maximum potential benefit from vaccination.

COVID-19 Booster Dose, Third Dose and Adult Vaccine (for Patients 12+)

  1. Is the Pfizer COVID-19 vaccine booster dose safe in adolescents 12-15 years of age?
    The FDA and CDC determined that the protective health benefits of a single booster dose of the Pfizer COVID-19 Vaccine to provide continued protection against COVID-19 in this age group outweighs the potential risks. To date, data from countries that have administered a Pfizer booster in this age population showed no new safety concerns.

  2. Do I need to receive a COVID-19 vaccine if I have been previously infected with COVID-19?
    Yes. The CDC recommends that even people previously infected with COVID-19 be vaccinated. This is because the immunity from vaccination appears to be more reliable than the immunity from natural infection. It is safe to get the vaccine as soon as you feel better and are out of isolation from COVID 19 infection. But you can choose to delay your vaccination until 90 days after your infection, because you can be fairly confident your immunity from the infection will last that long.

  3. Can I get the COVID-19 vaccine if I am pregnant?
    Pregnant individuals are at a higher risk of getting severe COVID-19. For this reason, the CDC, Society for Maternal- Fetal Medicine and American College of Obstetricians and Gynecologists strongly recommend that pregnant individuals have access to COVID-19 vaccines. A conversation with your obstetrical doctor or nurse might help you make a decision. For more information, visit the CDC website here.

  4. Who is now eligible to receive a booster shot?
    Everyone age 12 and older can get a booster dose. 

    • Teens, age 12-17 are eligible to receive the Pfizer BioNTech COVID-19 vaccine booster
    • Adults 18+ who have had their second shot at least 6 months ago for the Moderna or Pfizer vaccine, or received their Johnson & Johnson/Janssen vaccine at least 2 months ago, are eligible for a booster.
    • For more information on boosters, go here

  5. Do I need a note from my doctor to get a booster?
    You do not need a doctor’s note to receive a booster dose. You may be required to attest that you meet eligibility criteria to receive a booster.

  6. Do I need to bring my COVID-19 vaccine documentation when I get the booster shot?
    We encourage you to bring your original vaccine card or documentation, but it is not a requirement.

  7. Does my COVID-19 booster have to be the same brand as my initial series?
    The FDA and CDC allows for the use of a booster of a different brand than the original series although the benefits of this approach are not yet clear. Pfizer or Moderna are preferred in most situations. But in general, you can get the same vaccine brand that you received with your original series (example: Pifzer to Pfizer; Moderna to Moderna; J&J to J&J).

  8. What is the difference between an additional dose and a booster dose?
    1. Additional dose after a primary series: An additional dose of vaccine is administered when the initial immune response following a primary vaccine series is likely to be insufficient. For example, a third dose of COVID-19 mRNA vaccine for certain immunocompromised patients.
    2. Booster dose: Initial immune response to a primary vaccine series is thought to be adequate (For example, in immunocompetent individuals). But an additional dose of vaccine is administered when the initial immune response to a primary series is likely to have waned over time.

  9. Are the side effects similar for the booster dose?
    To date, the side effects reported after a booster dose of the Pfizer COVID-19 vaccine are similar to what people experienced after receiving doses 1 and 2. Pain at the injection site was the most commonly reported side effect. Most symptoms were mild to moderate and resolved within 3 days.

  10. Can I stop wearing masks and social distancing if I get a booster dose?
    While the booster dose of the vaccine may provide added protection, it is still recommended that you continue to follow state and local guidance as it relates to wearing a mask, maintaining social distance, hand hygiene, etc.

  11. Where else can I get the COVID-19 vaccine or booster dose if I cannot make it into Tufts Medical Center?
    You can check to find a vaccine clinic more convenient to you.

  12. Do you have a specific question about COVID-19 vaccines not answered here? Email your question to along with your name and city or town that you live in and we’ll answer your questions directly in our new weekly vlog from Tufts Medical Center Infectious Disease Physician and Hospital Epidemiologist Shira Doron.