What parents need to know about Pfizer’s COVID-19 vaccine for kids ages 5 to 11

In a clinical trial, no cases of unusual side effects after vaccination were reported

Lydia Melo receiving a covid-19 vaccine shot

Lydia Melo, 7, gets the first of two Pfizer COVID-19 vaccinations on September 28, 2021, as part of the vaccine’s clinical trial hosted at Duke University. FDA authorized the vaccine for 5- to 11-year-olds on October 29.

Shawn Rocco/Duke Health

Five to 11-year-olds are now eligible for a COVID-19 vaccine in the United States. 

The U.S. Centers for Disease Control and Prevention’s Advisory Committee for Immunization Practices recommended Pfizer and BioNTech’s vaccine for use in children ages 5 to 11 on November 2. The vote was unanimously in favor of offering the vaccine to this group, after committee members agreed that the benefits of vaccination outweigh the risks. CDC director Rochelle Walensky gave the final OK hours later.

“We know millions of parents are eager to get their children vaccinated and with this decision, we now have recommended that about 28 million children receive a COVID-19 vaccine,” Walensky said in a statement announcing the decision. “As a mom, I encourage parents with questions to talk to their pediatrician, school nurse or local pharmacist to learn more about the vaccine and the importance of getting their children vaccinated.”

Before ACIP’s vote, committee member and pediatrician Sarah Long of Drexel University College of Medicine in Philadelphia said she “couldn’t be more supportive” of recommending the use of the vaccine for 5- to 11-year olds. “We have one more vaccine that saves the lives of children,” she said.

Representatives for pediatric medical organizations, including the American Academy of Pediatrics and the American Academy of Family Physicians, also spoke before the vote in support of giving this age group access to the COVID-19 vaccine. “I have seen the devastating effects of COVID-19 infection,” said Pamela Rockwell, who practices family medicine in Ann Arbor, Mich., on behalf of the latter group. The vaccine will offer protection from the “very real and significant harms of COVID-19.”

The U.S. Food and Drug Administration officially issued an emergency use authorization for the vaccine on October 29. That authorization had passed its first hurdle October 26 when an FDA advisory panel gave a thumbs-up to make the vaccine available to 5- to 11-year-olds. 

The decision to endorse emergency use authorization of the vaccine followed an extensive discussion among experts on the FDA panel. Many panelists, for instance, expressed concerns about myocarditis, inflammation of the heart muscle. Myocarditis has been an uncommon, but potentially serious, side effect of the Pfizer and Moderna vaccines, primarily in male adolescents and young adults (SN: 6/23/21). Other experts emphasized that while children are less likely to develop severe COVID-19 than adults, kids aren’t spared from the worst of the disease. 

For Amanda Cohn, chief medical officer for vaccine policy at the CDC, the answer is clear. “We don’t want children to be dying of COVID, even if it is far fewer children than adults,” she said. “And we don’t want them in the ICU.”

FDA Advisory Committee member and pediatrician Jay Portnoy said at the meeting that Children’s Mercy Hospital in Kansas City, Mo., where he works, has been full for the last month or so, and many of the admitted kids have COVID-19. “I’m looking forward to being able to actually do something to prevent that,” he said.

And for children who have spent much of the last two years facing disrupted school and social lives, vaccination is a step toward normalcy. “It’s really to allow kids the freedom to be kids and do all the things comfortably that kids do,” Emmanuel Walter Jr., a pediatrician at Duke University School of Medicine and chief medical officer of the Duke Human Vaccine Institute said in an October 27 news briefing. Once vaccinated, children can go to school, play sports and “do the normal things kids want to do.”

Vaccinations are key to preventing disease, in adults and kids. Here’s what to know about kids, COVID-19 and the Pfizer vaccine. 

How has COVID-19 affected 5- to 11-year-olds?

As of October 28, 171 children in this age group in the United States have died of COVID-19, according to CDC’s COVID data tracker. Looking at the top 10 causes of death for children in 2019, COVID-19 would be eighth on that list, said Fiona Havers, a medical officer with the CDC’s COVID-19 Public Health Response during a presentation at the FDA meeting. More than 8,300 kids ages 5 to 11 have been hospitalized so far, and about a third of those needed intensive care, she said. 

The inequities that have been seen throughout the pandemic have not spared younger children. Among 5- to 11-year-olds, the hospitalization rate is three times as high for Black, Hispanic and American Indian/Alaska Native children as it is for white children, Havers said. Advisory committee member and immunologist James Hildreth, who is president of Meharry Medical College in Nashville, said the primary reason for his yes vote was to make sure that “the children who really need this vaccine, primarily the Black and brown children in this country, get the vaccine.”

The overall rate of hospitalization for COVID-19 for 5- to 11-year-olds roughly matches what was seen for influenza seasons before the pandemic. But that’s with masking, school closures and other public health measures. Without those precautions, the COVID-19 hospitalization rate may be higher than that seen in past flu seasons, Havers said.

More than 5,000 children who were infected with the coronavirus have developed multisystem inflammatory syndrome in children, or MIS-C, which causes severe inflammation throughout the body. Of those reported cases, 39 percent were among children ages 6 to 11, Havers said. 

Children can also experience long COVID, in which symptoms such as fatigue, cough, headaches, insomnia, difficulty concentrating and pain in the muscles and joints persist after being sick. These continued symptoms can limit activity and impact mental health and school attendance. Long COVID can occur after mild or severe disease or following MIS-C. It’s still unclear how many children have been affected by long COVID. One estimate, from a survey by the United Kingdom’s Office for National Statistics, reported that 7 to 8 percent of U.K. children who had gotten COVID-19 still had symptoms more than 12 weeks after being diagnosed. 

COVID-19 has severely disrupted children’s lives beyond its capacity to cause illness. Children have been kept out of school, which has stalled the education of many kids, and for many has meant missing out on regular meals. School closures that happened during just a few months, from August to October of 2021, as the delta variant was surging, affected more than 1 million students in the United States. We don’t yet know the extent of the educational and emotional toll school closures have taken on children (SN: 8/10/21).

How was the vaccine evaluated?

In a clinical trial, Pfizer assessed the immune response and the safety of their mRNA vaccine in kids 5 to 11. The trial included about 2,250 children, with two-thirds getting the shot and the other third receiving a placebo. 

An earlier study had determined that this age group had a good immune response to a smaller dose, two shots of 10 micrograms, compared with the 30-microgram-per-shot dose given to adolescents and adults. Children’s immune systems tend to respond well to vaccines, so to avoid unnecessarily strong symptoms after a shot, such as high fevers or excessive achiness, the goal with the smaller dose is to hit the right sweet spot between a protective immune response and side effects (SN: 2/25/21).

How well does the vaccine work?

The data suggest the vaccine works very well for this age group.

Pfizer assessed kids’ immune response to the vaccine by looking at antibody levels. The company compared the response in a group of 5- to 11-year-olds one month after the second shot with antibody levels seen in a group of 16- to 25-year-olds, who were part of the earlier and much larger clinical trial that studied the vaccine’s efficacy in tens of thousands of adults (SN: 10/4/20). There was no difference in the immune responses between the different groups, even though the younger children received a smaller dose, the FDA reported in their review of Pfizer’s trial data. Since the immune response was similar between the two groups, the protection against COVID-19 offered by the vaccine for each group should also be similar.

Pfizer also looked at how many symptomatic COVID-19 cases occurred at least a week after the second shot in children who were vaccinated compared with those who received the placebo. Three of 1,450 vaccinated children developed the disease, while 16 of 736 unvaccinated did, which Pfizer reports as an efficacy of 90 percent. None of the children in the trial had severe COVID-19 or MIS-C.

boxes and vials of the Pfizer covid vaccine
To avoid confusing vaccine vials dosed for kids versus people 12 and over, Pfizer has changed the color scheme that it uses for younger individuals getting their shots. The vials for 5- to 11-year-olds will have an orange cap and box label, while the vials for older individuals are marked by purple caps and labels.Pfizer

What are the side effects?

In the clinical trial, common side effects were redness, swelling and pain at the site of the injection in the arm, as well as headache and fatigue. There were no cases of anaphylaxis, a severe allergic reaction that was reported, though rarely, when the Pfizer vaccine was first given to adults outside clinical trials (SN: 1/6/21). 

What about heart inflammation called myocarditis?

No cases of myocarditis occurred in kids ages 5 to 11 in the follow-up period, three months after vaccination. But with the possibility that this rare complication could occur once the vaccine is used in larger numbers, weighing the risk of myocarditis against the benefits of being protected against COVID-19 disease, hospitalization and death took up much of the discussion at the FDA’s advisory panel meeting. 

Tens of millions of doses of COVID-19 vaccines have been given to 12- to 29-year-olds. Of 877 confirmed myocarditis cases in this group and 829 hospitalized, there have been no deaths. As of October 6, 607 of 789 adolescents and young adults discharged from the hospital are known to have recovered from their symptoms. 

Myocarditis can also occur with COVID-19. Patients with the disease had 16 times the risk for myocarditis as patients without the disease, according to a study of U.S. hospital data from March 2020 to January 2021. 

The FDA and CDC have several post-vaccine safety surveillance systems in place. “We will continue to actively look for adverse events,” said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research in Silver Spring, Md., at the advisory meeting. The CDC and the FDA “are incredibly committed and devoted” to catching any safety issues as soon as possible, he said.

When myocarditis occurs in the general population, due to infection or other causes, it tends to happen after puberty. Based on the lower typical rate for younger kids and the lower vaccine dose that this group will receive, “I am not as concerned about myocarditis,” said Melinda Wharton, associate director for vaccine policy at CDC’s National Center for Immunization and Respiratory Diseases in Atlanta. Authorizing the vaccine “is a good move forward for COVID prevention and for protecting our kids.”

How can parents be sure children are getting the correct, smaller dose?

The vials of Pfizer vaccine intended for those 12 and older have a purple cap and purple lettering on the label. 

To help make sure that 5- to 11-year-olds get the right vial, the company has changed the color scheme to orange.

Should 11-year-olds wait until their 12th birthday to get the same dose that adults do? 

“I would not wait,” said Walter, the Duke pediatrician, who was involved in the clinical trial for Pfizer’s vaccine. 

That’s because even with the lower dose of the vaccine, 11-year-olds developed lots of antibodies. Data presented during the October 26 FDA advisory meeting show that 5- to 11-year-olds had similar antibody levels as older age groups a month after the second dose. “I’m confident they’ll have the same protection” as 12-year-olds, Walter said. 

How can parents prepare kids to get the vaccine? 

The shots can have typical side effects like fever or fatigue. So it may be worth telling children that they might feel achy, have a headache or just not feel good overall for the next day or so, Walter said. “That’s to be expected.” 

Those symptoms are usually pretty mild. But some kids may end up with stronger side effects, such as feeling more fatigued, than others. If your child does end up feeling crummy, Walter said, it’s OK to use pain medication.

Aimee Cunningham is the biomedical writer. She has a master’s degree in science journalism from New York University.

Erin I. Garcia de Jesus is a staff writer at Science News. She holds a Ph.D. in microbiology from the University of Washington and a master’s in science communication from the University of California, Santa Cruz.