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Coronavirus (COVID-19): What Are Booster Shots?

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I’ve heard that it’s important to get a booster shot of the COVID-19 vaccine to be as protected as possible from the virus. Do kids need a booster shot too?

Yes, booster shots are now recommended for everyone age 12 and older.

To understand why, it helps to know what a booster shot is. This is a dose of vaccine given after a person has had the original vaccine (sometimes called a primary dose or, if more than one dose, primary series). Immunity from the original vaccine can fade over time, and a booster shot can help the immune system “boost” the protection it provides.

Boosters aren’t new. They are given for many vaccines that kids and adults get. For example, kids get vaccines around the time they start school to boost the vaccines they got as infants and toddlers. Pregnant women get a Tdap booster to protect their newborn from pertussis. And anyone over 6 months old should get a flu shot each year, which is also a type of booster.

Why Do People Need a COVID-19 Booster Shot?

Safe and effective COVID-19 vaccines are recommended for all adults and children ages 5 and up. They are very good at preventing serious illness, hospitalization, and death due to COVID-19. Children up to age 18 get two doses for their primary series.

As with other vaccines, the immune protection from the COVID-19 vaccine can fade over time. A booster shot is recommended for everyone age 12 and older when 5 months have passed since their primary series. And a second booster dose is available for some groups of people, including adults 50 years and older, and adolescents who have weak immune systems.

Is a COVID-19 Booster Shot the Same as an "Additional Dose" or a "Third Dose"?

No. An additional dose is an extra dose of vaccine given as part of the primary series when a person is first vaccinated. Some people with weak immune systems might get a poor response from the primary series of the COVID-19 vaccine. This can include people who are being treated for cancer, have had an organ transplant, or take medicines that weaken the immune system. This added dose helps their immune system reach the same level of protection as in people with stronger immune systems.

For kids ages 5 and older who need it, the additional dose is usually given 28 days after they get their second dose. That’s why it’s sometimes called a third dose.

People who get an additional dose in the primary series will still need a booster as time passes, just like everyone else. But they should get their booster after 3 months instead of 5 months. They now can also get a second booster dose, 4 months after their first booster. So, teens with weak immune systems will get a total of 5 shots.

What Does It Mean for My Family?

Being up to date on COVID-19 vaccination might mean a different number of doses for kids in different health situations. But it’s an important way to protect kids and adults from getting very sick. Talk to your doctor if you aren’t sure if your child needs an additional dose after their primary COVID-19 vaccine series, or to see when your child might need a booster shot.

Date reviewed: April 2022