Everything Parents Need To Know About The Under-5 COVID Vaccine

Including what to do if your child is about to turn 5 and whether you should choose Pfizer or Moderna.

Originally Published: 
Close up of a doctor giving a child under 5 the COVID vaccine.
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The road to the COVID vaccine for kids under 5 has been undeniably long, but it has finally come to an end: The youngest children can now officially get their COVID shot. This means that, after clinical trials on thousands of kids across the nation, approximately 17 million children under the age of 5 are now eligible to get vaccinated. Although many parents are still hesitant about getting their kids immunized, experts note that the data is promising and reassuring — and waiting until more kids get their shot and potentially contracting COVID in the meantime is by far the riskier option.

“For the year and a half now that we've had vaccines out there, we haven't had anything for those less than 5 years old,” says Paul A. Offit, M,D, director of the Vaccine Education Center and a doctor at the Division of Infectious Diseases at Children's Hospital of Philadelphia. “During that time, about 45,000 children in that age have been admitted to the hospital over the last two years, about 10,000 had to go to the intensive care unit, and about 450 have died.”

Now, both the Moderna vaccine — two doses, 25 micrograms each, four weeks apart — and Pfizer vaccine — three doses, three micrograms each, the first two doses being three weeks apart and the third dose following eight weeks later — are available for kids in this age group. The vaccines provide some protection against infection, but more importantly, against severe disease.

“Finally we have another layer of protection in addition to masks, which is vaccines,” says Offit, who was on the FDA’s committee of independent vaccine experts who voted unanimously to recommend the shots. Here, he answers parents’ most pressing questions about the under-5 COVID vaccine.

Is the COVID vaccine for kids under 5 safe?

Pfizer safely tested its vaccine on 4,500 children under the age of 5 and Moderna on 6,700 children under the age of 6. In these groups, there were no serious adverse reactions.

Scientists are confident about the under-5 vaccine being safe, even though the medical definition of safety is never absolute safety, but that its benefits clearly outweigh its risks. “Do I think that the vaccines are absolutely safe? No. There are no risk-free choices. But I think the choice not to get a vaccine is the riskier choice,” Offit says.

One of the concerns for scientists is the possibility of the vaccine causing rare cases of myocarditis or pericarditis — inflammations of the heart muscle. But the trials on Moderna and Pfizer for under-5s reported no case of either. The risk of myocarditis has been less and less of an issue the younger vaccine recipients are. “So I think it'll be an even lesser issue here,” Offit says.

Does the COVID vaccine for kids under 5 work?

According to the trials so far, both vaccines aren’t as effective in protecting against symptomatic infection for younger children as they have been for adults. However, the shots do protect against severe infection.

Although not enough children in the Pfizer trial were infected with COVID for scientists to determine the exact efficacy of the vaccine, experiments suggest that the Moderna vaccine is between 38% and 51% protective against symptomatic disease. Its efficacy is likely much higher against severe disease, Offit says.

How bad are the side effects?

For both vaccine brands, reported side effects have been mild or moderate and similar to those in adults, with no major safety concerns. Side effects include soreness where they’ve been injected, chills, fatigue, headache, and fever.

Fever is one of the most common side effects, occurring in 21% to 26% of kids who receive the Moderna vaccine and 7% of children who get Pfizer’s. “But that's what happens when you develop a vigorous immune response; you develop a fever,” Offit says. Fever is a manageable side effect; it can be mitigated with over-the-counter medicine, and it doesn’t cause permanent damage.

Should I wait and see?

“While you're waiting, you're taking a risk,” says Offit. “While you're waiting, the virus is circulating and it might affect your child.”

More than a billion people have been immunized with mRNA vaccines, including millions of children between the age of 5 and 11. “Maurice Hilleman, who was the father of modern vaccines, said, ‘I never breathe a sigh of relief until the first three million doses are out there.’ Well, the first three billion doses are out there,” Offit says.

Don’t let summer fool you either. Just because kids will be spending more time outside and school classrooms will be empty until fall doesn’t mean you should delay getting the vaccine, said Leslie Sude, M.D., a pediatrician at Yale Medicine, in a Yale Medicine blog post.

What if my kid has had COVID?

Wait until your child doesn’t have symptoms, and then go ahead and get the vaccine, Offit says. If they’re asymptomatic, they can receive their vaccine, Offit says.

There are benefits to both types of immunity — immunity from getting the virus and immunity from getting vaccinated. But the best type of immunization might be hybrid immunity, some evidence suggests. So even if your child has contracted COVID, it’s still helpful to get them vaccinated.

Does my child need all the doses?

Yes, it’s important to get both Moderna shots or all three Pfizer shots. According to Offit, soon there will be approval for Moderna to also become a three-shot vaccine, potentially as soon as July, so recommendations may slightly change in the near future.

If my kid is about to turn 5, should I wait for them to age up to the vaccine for older kids?

“I think you should get the vaccine while you can get it, which is now. So get the one that’s appropriate for their age,” Offit says.

Of course, there will be some cases of children who turn 5 during their vaccination period, and this could make a difference in the dosage they receive; for children under age 5, the Pfizer vaccine is three doses of three micrograms, for example, and for those over the age of 5, it’s two doses of 10 micrograms.

Experts recommend that children get vaccinated as soon as possible, and they might get bumped to a higher dosage once they turn 5, per American Academy of Pediatrics recommendations.

Which is better: Pfizer or Moderna?

Once again, Offit suggests you get whichever vaccine you have access to most easily, because it’s crucial to act quickly. And until there’s more real-world data, we won’t really know which vaccine is better.

However, immunity from the Moderna vaccine kicks in sooner. Kids need to wait up to 14 weeks to get full immunity from all of Pfizer’s doses, but it only takes six weeks before the Moderna immunity kicks in. “I think you get sooner protection, quicker protection with the Moderna vaccine,” Offit says.

Is there any reason at all why my kid shouldn't get the under-5 COVID vaccine?

You should get your child vaccinated unless they’re allergic to something in the vaccine, but that’s very, very rare, Offit says, especially because we all have mRNA in our cells to start with. Your child is probably eligible for the COVID vaccine even if they’ve had allergic reactions to other vaccines before, but you should check with your family doctor.

Where can I get my child vaccinated?

Call your pediatrician or check out to find the nearest vaccine clinic for children near you.

“This virus is smarter than we ever imagined,” Ruth Karron, M.D, director of the Johns Hopkins Center for Immunization Research, said in the podcast Public Health On Call. Omicron and its subvariants are more transmissible than measles — one of the most infectious diseases we know of, according to Karron. And the CDC has estimated that 1,200 children — healthy children — have died of COVID. “This is a tragedy,” she said. “Whatever we can do to avoid this tragedy is something we should do.”

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