Here’s What to Know About COVID-19 Booster Shots for Kids

Children were always going to be the toughest group to vaccinate against COVID-19, so it’s no coincidence that they were the last group to receive authorization for the shot; manufacturers and government agencies want to be extra careful to find the right dosing and safety profile for the youngest Americans.

The same is true for boosters. Here are answers to some frequently asked questions about boosters for kids.

Which children are eligible for a booster?

On May 19, the U.S. Centers for Disease Control and Prevention (CDC) expanded eligibility of the Pfizer-BioNTech booster for all Americans as young as age five and recommended that everyone in that age group receive a booster. “The primary goal of vaccination is basically to keep everyone from getting very sick,” says Dr. Stan Spinner, chief medical officer and vice president of Texas Children’s Pediatrics and Texas Children’s Urgent Care. “Studies have shown that just like in adults, immunity from the primary series of the Pfizer-BioNTech vaccine did tend to wane. Giving children five to 11 years old a single booster dose increased their immune response to give them more hearty protection against getting infected, and very robust protection against more serious consequences of COVID-19 that can lead to hospitalization or death.”

Right now, children can only receive the Pfizer-BioNTech vaccine as a booster. That may change in mid-June, after the U.S. Food and Drug Administration (FDA) and CDC complete their review of data submitted by Moderna on the safety and efficacy of its shot for children.

When should children receive a booster dose?

The CDC recommends that children should get a booster dose five months after finishing their primary COVID-19 vaccination series of two shots. For children ages 12 and up, that means a booster the same dose as their primary series, which is the same dosage given to adults. For children ages 5 to 11 years old, that means a dose one-third that of adults.

For children with weakened immune systems, their primary series is actually three doses of the vaccine, which gives them the strongest immune response possible and can reduce their risk of needing to be hospitalized or dying from COVID-19.

The CDC recommends booster shots for immunocompromised children—which would be a fourth dose—based on their age. Children ages five to 17 years old with weakened immune systems should get a booster dose three months after receiving their three-dose primary series. Immunocompromised children ages 12 and older should also get boosted a second time—a fifth dose—four months after the first booster dose to keep their immune responses as active as possible.

How effective are the vaccines and booster doses in children?

When paired with a booster, the COVID-19 vaccine is 80% to 90% effective in continuing to protect youngsters from the more serious consequences of COVID-19. “The immune response seen in children is fairly comparable to that seen in adolescents and adults,” says Spinner.

Are the vaccines and boosters safe in children?

Studies have shown that the Pfizer-BioNTech vaccine is safe in children. Research has found that a very small number of older children have experienced multisystem inflammatory syndrome in children (MIS-C), a rare disorder in which the body’s immune system generates an aggressive inflammatory response, after getting vaccinated, and MIS-C is currently listed as a potential adverse event in the CDC’s vaccine safety monitoring system. But it’s not clear whether the vaccine is associated with the condition, or whether the children developing it have also been infected with the virus, since SARS-CoV-2 itself is known to be linked to MIS-C.

The vaccines have also been associated with a small number of cases of inflammation of heart tissues, mostly in adolescent males. The CDC continues to recommend COVID-19 vaccination for children, based on the evidence that the benefits of immunization outweigh these potential risks.

Should I wait until fall to get my children boosted so they are protected before they go to school?

With cases of COVID-19 rising in most parts of the country, doctors urge parents to get their children vaccinated and boosted as soon as possible. “When there is enough virus in the community—which there is now—and the risk of getting infected becomes higher—which it is now—delaying vaccination makes no sense,” says Spinner. “Kids are out and about, fewer people are wearing masks, kids are going to camps and play groups, so they are going to get exposed during the summer. Why wait to immunize your child?”

Will children have to continue to receive boosters every few months?

Public-health experts at the CDC are reviewing the data to answer this question, not just for children but also for adults. So far, every authorized COVID-19 vaccine has been developed using the original strain of SARS-CoV-2. Fortunately, the vaccines have remained effective in generating strong immune responses to the different variants of the virus that have emerged. But health experts and vaccine makers have recently developed new, not-yet-authorized vaccines targeting the latest variants, including Omicron, and are studying whether those shots might produce even stronger, and hopefully longer lasting, protection against serious disease.

Can babies and toddlers get vaccinated or boosted yet?

Not yet. No COVID-19 vaccine has been authorized for the youngest children—those ages six months to four years—but the FDA’s independent panel of experts will be reviewing the safety and efficacy data on immunizing these children on June 14-15, 2022.

The FDA and CDC are reviewing data from two vaccine makers, Pfizer-BioNTech and Moderna, which submitted studies on the safety and efficacy of their vaccines for children ages six months to four years (for Pfizer) and six months to six years (Moderna). Moderna’s data show that two doses of its vaccine, at a quarter of the dose used for adults, help these children generate similar levels of virus-blocking antibodies as adults. Pfizer-BioNTech announced similar efficacy with its vaccine, except after three doses and at a third of the dosage used for children 5 to 11 years old.