Health library

Back to health library

6 questions about COVID-19 booster shots

A standing woman smiles down at a seated man.

The rollout of booster shots for COVID-19 vaccines might naturally raise some questions. Here's a closer look at some things you might want to know if you're weighing your options.

Q. Who is eligible?

A. Boosters are aimed at increasing the effectiveness of the vaccine.

People 5 and older who received the Pfizer vaccine are eligible five months after their initial series, as are all adults who received the Moderna vaccine.

Everyone 18 and older who received the Johnson & Johnson (J&J) vaccine is eligible two months after their initial shot.

Q. Who needs a booster shot?

A. According to the Centers for Disease Control and Prevention (CDC), everyone eligible should get a booster. Some people may need a second booster four months after the first.

Q. How soon can I get a shot?

A. Booster shots are available now at most pharmacies and vaccines clinics across the country. Check your local pharmacy or clinic to schedule an appointment. Walk-ins may be welcome too.

Q. What are the expected side effects from a booster shot?

A. In trials, the side effects of the booster shot were the same as the first two doses of the vaccine. That included things like:

  • Pain in the injection area.
  • Joint and muscle pain.
  • Headache.
  • Fever.
  • Nausea.
  • Diarrhea.

Q. Do I need the bivalent booster shot if I have already had a booster?

A. Even if you've had a booster shot, an updated booster dose can offer added protection. CDC recommends it for everyone 12 and older. You can get this booster if it has been two months since your last booster shot or your final dose of the COVID-19 vaccine. 

  • .

Q. Will I still be considered fully vaccinated if I don’t get a booster shot?

A. Yes, for now. CDC says everyone who has received two doses of the Pfizer or Moderna vaccine or one dose of the J&J vaccine is still considered fully vaccinated. That guidance may evolve over time.

Q. Can I mix and match vaccines?

A. Yes. If you're an adult, your booster does not have to be the same as the vaccine you originally received. You should choose either the Moderna or Pfizer vaccine. The only booster authorized for people 5 to 17 years old is the Pfizer vaccine. The Novavax vaccine is not authorized for use as a booster dose.

For more helpful information, please visit our Coronavirus health topic center.

Reviewed 9/8/2022

Read more breaking news Related stories