Conversation Guide: Boosters and Third Doses

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What is a booster?

Boosters are shots you get after you are fully vaccinated so that you can stay protected against COVID-19.

What is a third dose?

Some people with certain health conditions need a third shot of the Pfizer (Comirnaty) or Moderna vaccine to be fully protected, because their bodies cannot build enough protection from two shots. This is uncommon.

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What is the difference between a booster and a third dose?

People with certain health conditions need three shots to become protected against COVID-19. People who have a higher risk of catching COVID-19 or getting seriously ill should have a booster to make sure they stay protected.

Do boosters mean the vaccines don’t work?

COVID-19 vaccines are very effective. If you are fully vaccinated, you are unlikely to get infected with COVID-19 and spread it to loved ones. Even if you are infected, the vaccine prevents you from getting seriously ill or dying.

Boosters are common for many vaccines. For example, tetanus vaccines require boosters every 10 years for adults. Scientists have found that with some vaccines a person’s protection decreases over time, and a booster helps them stay protected. The COVID-19 booster works the same way.

While boosters may increase protection, people who are fully vaccinated continue to have good protection against severe illness and hospitalization without a booster.

Are boosters safe?

Yes, boosters are very safe. Boosters have the same ingredients as the original vaccines, which have been proven safe for hundreds of millions of people. Most people who receive boosters experience the same mild side effects as they did when they got their second shot. Serious side effects are very rare, and most people who have them get better.

I am fully vaccinated. Do I need a booster?

COVID-19 vaccines protect against severe illness, hospitalization, and death, even against the Delta variant. However, boosters are recommended for some people who have a higher risk of catching COVID-19 or getting seriously ill. 

Whether someone needs a booster depends on their age, health history, job, living situation, and which vaccine they received before. Talk to a doctor or other healthcare professional to see if a booster would be good for you.

If I don’t get a booster, am I still considered fully vaccinated?

Yes, you are still considered fully vaccinated if you do not get a booster. While boosters may increase protection, people who are fully vaccinated continue to have good protection against severe illness and hospitalization without a booster.

What is the point in getting vaccinated if I will keep needing boosters?

If you are fully vaccinated, you are unlikely to get infected with COVID-19 and spread it to loved ones. Even if you are infected, the vaccine prevents you from getting seriously ill or dying. COVID-19 vaccines even protect against the Delta variant.

What do I do if I have more questions about boosters?

Contact your doctor, pharmacist, or another health professional if you have more questions.