Your Questions About the Coronavirus Vaccine and Children, Answered

Yes. While children are less likely to develop severe cases of COVID-19 than adults, they’re just as likely to be infected. Some require hospitalization, and some have died. Adolescents have been more likely to develop a serious case like adults, says Kathryn Edwards, MD, scientific director of the Vanderbilt Vaccine Research Program and a professor of pediatrics. Vaccination will help protect against severe disease and death.

The emergence of the omicron variant, which is significantly more transmissible than earlier variants, heightened the importance of vaccination for everyone 5 and older, according to the CDC.

Even if a particular variant isn’t more dangerous for kids, any increase in contagiousness means that a lot more of them will end up in a hospital, says Sean O’Leary, MD, a professor of pediatrics at the University of Colorado School of Medicine and an infectious disease specialist at Children’s Hospital Colorado. That highlights the urgency of getting more people—kids and adults—vaccinated. Surges in pediatric hospitalizations have been especially bad in places with lower vaccination rates for adults and adolescents, he says.

As of June 15, there have been at least 2.5 million cases of COVID-19 in kids 4 and younger. There have been at least 5.1 million cases of COVID-19 in children ages 5 to 11, and in that age group at least 3,136 cases of multisystem inflammatory syndrome (MIS-C). That’s a condition where parts of the body—including the heart, lungs, brain, and other organs—can become inflamed, potentially leading to organ damage or death. During a Nov. 2 advisory group meeting, the CDC reported that there had been at least 8,300 hospitalizations among those in this age group due to COVID-19, and at least 94 deaths from MIS-C.

Vaccination also helps prevent other serious outcomes in children. Many of those who get COVID-19—including many who were never hospitalized—deal with lingering symptoms that can persist long after infection, says Tina Tan, MD, a pediatric infectious disease specialist and professor of pediatrics at Northwestern University in Chicago. A national survey in the United Kingdom found that 7 to 8 percent of children with COVID-19 had symptoms that continued more than 12 weeks after their initial diagnosis.

Yes. They have provided strong protection against severe disease for kids. But as with adults, the vaccines have been less effective at preventing infections with the omicron variant—with even less protection against overall infection for younger children, who get smaller vaccine doses. Data indicates that booster shots can effectively restore waning protection, which is why on May 17 the FDA expanded authorization for booster doses so anyone 5 and up would be eligible for one.

In late October, when the Pfizer-BioNTech vaccine was authorized for children ages 5 to 11—and the delta variant of the coronavirus was circulating—clinical trial data indicated that the vaccine was 90.7 percent effective at preventing symptomatic infection with COVID-19 in this age group. But the omicron variant, which can evade some of the protection provided by vaccines, has complicated the picture, with the vaccines demonstrating less protection against mild to moderate infections. 

On Feb. 28, researchers affiliated with the New York State Department of Health released a preliminary, not-yet-peer-reviewed study (PDF) that found that as omicron took over, vaccine protection against infection dropped for everyone—and especially for younger kids. From Dec. 13, 2021, to Jan. 30, 2022, vaccine protection against infection fell from 66 percent to 51 percent for 12- to 17-year-olds. For 5- to 11-year-olds, the fall was more precipitous—from 68 percent protection against infection to just 12 percent.

One likely explanation for lower efficacy in younger children, according to the study authors, is that they received smaller doses of the vaccine, with 5- to 11-year-olds getting two 10-microgram vaccine doses instead of the two 30-mcg doses that older adolescents and adults get. The clearest example of this can be seen by looking at the difference between 11- and 12-year-olds. From Jan. 24 to Jan. 30, during the omicron surge, vaccine efficacy against infection for kids age 11 was 11 percent, while efficacy against infection for 12-year-olds was 67 percent.

A CDC study released on March 11 also suggests that vaccines may be slightly less effective in younger children. It found that vaccines were about 31 percent effective at preventing symptomatic and asymptomatic omicron infection in kids ages 5 to 11, and about 59 percent effective in kids ages 12 to 15. Still, the authors wrote that while symptomatic kids spent an average of two days sick in bed, vaccinated children spent about a half-day less in bed.

Indeed, despite the waning protection against infection, the vaccines still provided solid protection against severe disease in all age groups, according to the New York study. By Jan. 24, efficacy against hospitalization appeared to be about 73 percent for 12- to 17-year-olds and about 48 percent for 5- to 11-year-olds—rough estimates because few children were hospitalized.

An earlier CDC study released on March 1 also reported solid vaccine protection against severe illness for kids who were largely facing the omicron variant. Researchers looked at 39,217 trips to emergency rooms and urgent care centers by children and adolescents. Being fully vaccinated was about 46 percent effective at preventing visits to the ER or urgent care for kids ages 5 to 11. (Efficacy against hospitalization was better, at about 73 percent, though there were very few hospitalizations, making this a very rough estimate with a wide confidence interval.)

That CDC study found that for older kids who had received a second vaccine dose within the previous five months, protection against going to an ER or urgent care was similar: 45 percent efficacy for adolescents ages 12 to 15, and 34 percent efficacy for those ages 16 and 17. It had been much higher during the delta surge. A booster shot restored vaccine efficacy against visiting an urgent care or ER to 81 percent among 16- and 17-year-olds.

For the youngest kids, efficacy has largely been estimated by the levels of antibodies generated in the vaccine trials.

Depending on how efficacy is calculated, two very low doses of Moderna’s vaccine appeared to be between 36.8 percent and 46.4 percent effective at preventing infection in kids ages 2 to 5. For those ages 6 months to 2 years, the vaccine appeared to be about 53.5 percent effective at preventing infection.

Pfizer and BioNTech’s vaccine required three doses to be effective. An analysis of trial data estimated that those three doses were about 80 percent effective at preventing infection. But this was based on such a small number of COVID-19 cases that it’s not clear how representative it is of real-world efficacy.

In both cases, the vaccines appeared to provide enough of a benefit for young kids that the FDA’s advisory panel recommended their authorization unanimously. It will take some time before more accurate estimates of effectiveness in the real world appear. But the vaccines will also probably lower the risk for severe disease, just as they have for older kids and adults.

Older kids do; younger ones get smaller doses.

In Pfizer-BioNTech’s clinical trial, 12- to 15-year-olds received the same vaccine and 30-microgram dosages as adults, on the same schedule, with a second dose three weeks after the first. The FDA’s authorization for the Pfizer-BioNTech vaccine allows 12- to 15-year-olds to get the same dose as adults.

To reduce the risk of myocarditis, the CDC announced on Feb. 22 that it may be best for males ages 12 to 39 to get their second vaccine dose eight weeks after the first, instead of three weeks later (and instead of four weeks later for Moderna shot recipients, but this isn’t an option for anyone under 18).

Adolescents ages 12 to 17 are eligible for a booster shot five months after their second dose.

Children ages 5 to 11 get two shots, each a smaller 10-mcg dose, three weeks apart. Doses for children ages 5 to 11 come from orange-capped vials. (The vials for older children and adults have purple caps.) The vaccines for these children are available in pediatricians’ offices, clinics, and pharmacies. On May 17, the FDA authorized a booster dose for those in this age group as well, also five months after dose two.

Moderna’s vaccine for kids ages 6 to 17 consists of two 50-mcg doses, half the dose that adults get.

For kids under 6, the Moderna vaccine consists of two 25-mcg doses, given four weeks apart, the same time frame for other Moderna vaccinations.

For kids under 5, the Pfizer-BioNTech vaccine consists of three doses of a 3-mcg shot. The second dose is given three weeks after the first, and the third at least eight weeks after the second.

Yes. Common side effects reported in children are similar to those in adults: injection-site pain, fatigue, headaches, muscle aches, chills, joint pain, and fever. And as seen in other age groups, these were “well-tolerated” in 12- to 15-year-olds, Pfizer and BioNTech say.

“The reaction profiles were pretty comparable to what we see in adults,” says Kathryn Edwards at Vanderbilt.

In mid-May 2021, the CDC announced that it was investigating rare reports of heart inflammation—myocarditis and pericarditis—that have occurred after coronavirus vaccination, and the agency released additional data in June.

These cases occurred mostly in male patients and have been more common after the second dose than the first. There have been more reports of suspected myocarditis in people ages 16 to 24 after vaccination than would be expected for that population, according to CDC data.

But while it’s important that the CDC be transparent about these investigations, parents should understand that these events are still extremely rare, says David Parra, MD, a pediatric cardiologist and an associate professor of pediatrics at Vanderbilt University. Plus, the CDC says that while in general, the severity of myocarditis cases can vary, the cases that have occurred after vaccination have responded well to medication and rest. Most of the people who have developed myocarditis after vaccination have had mild cases and have recovered quickly, according to a study published in the journal Circulation.

According to a CDC study released March 1, there are about 70.1 confirmed cases of myocarditis after a second vaccine dose per million boys ages 12 to 15 vaccinated, and about 105.9 cases in boys ages 16 or 17 per million doses. An earlier CDC analysis reported that in this same age group, a million vaccinations would prevent 5,700 cases of COVID-19, 215 hospitalizations, 71 intensive care unit admissions, and two deaths. Rates of myocarditis after a booster are much lower: 11.4 cases in adolescent boys per million doses, according to the study. This could be due to the long interval between doses, another reason the CDC now suggests spacing out the first and second dose more for adolescent boys.

Children ages 12 to 15 appear to have lower rates of myocarditis after vaccination than people ages 16 to 29, something that several members of the FDA advisory panel said made them more comfortable recommending authorization of the vaccine for kids ages 5 to 11. While the cause of myocarditis in young men is still unknown, some research suggests that it could be linked to testosterone, which could make the risk for younger, prepubescent children lower.

After the first 7.1 million vaccine doses were administered to children ages 5 to 11, there were eight reported cases of myocarditis, according to CDC data. It’s not clear that all of these were linked to the vaccine, and this is a lower rate than that seen in older children.

Younger children are expected to be less likely to develop myocarditis, according to Matthew Oster, MD, a pediatric cardiologist at Children’s Healthcare of Atlanta and a member of the CDC’s COVID-19 task force, who presented myocarditis data on children ages 5 to 11 at a Nov. 2 meeting of a CDC advisory group. The data also appears to indicate that for adolescents and young adults, vaccine-associated myocarditis is milder and resolves more quickly than traditional myocarditis, Oster said.

Initially, in some countries, including the U.K. and Norway, health officials recommended only a single dose for adolescents, to lessen the risk of side effects. But both countries have now concluded that a second dose is safe, though they recommend it eight to 12 weeks after the first dose.

We also know that COVID-19 itself can cause inflammation in the heart and other organs, Parra says. “Vaccination is really important, and from what we know, the risks of COVID are much higher than the risks of vaccination,” he says.

According to a September CDC report, kids younger than 16 who get COVID-19 are 37 times more likely to develop myocarditis than kids without COVID-19. That’s a significantly higher risk than the myocarditis risk associated with vaccination. “Getting COVID is much riskier to the heart,” Oster said at the CDC discussion.

Myocarditis was not seen in the vaccine trials for the youngest kids. Common side effects included headaches, pain at the injection site, and fevers.

Now that the CDC has recommended the COVID-19 vaccine for kids 6 months to 5 years old, all children 6 months old and up are eligible, and shots could become available by June 21 or even sooner.

More than 1,000 colleges and universities in the U.S. have required students to be vaccinated against COVID-19, though dozens of schools have rolled back vaccine mandates for students or staff after various legal challenges, according to the Chronicle of Higher Education. Some high schools have started to issue requirements as well, although implementing them is taking time. The school board for Los Angeles public schools, for example, delayed the requirement that students 12 and older be vaccinated by Jan. 10, 2022, to the fall.

Schools that serve younger children already often require proof of various immunizations before children enroll, but it’s not yet clear whether a COVID-19 vaccine will become one of them.

Right now, COVID-19 vaccines have an emergency use authorization from the FDA for kids from 5 to 15. Until vaccines receive full approval for younger age groups, Poland says he thinks most schools probably won’t require kids to have one. But after the FDA fully approves the vaccines for children, many schools are likely to require proof of vaccination, he says.

Edwards says she hopes that people are persuaded to get children vaccinated based on the “incredible success” we’ve seen the vaccines have at preventing disease so far.