Pfizer requests authorization of COVID-19 vaccine for kids under 5: What to know

(WASHINGTON) — Nearly two years into the coronavirus pandemic, children ages 5 and under are one step closer to being eligible to be vaccinated against COVID-19.

Pfizer on Tuesday asked the U.S. Food and Drug Administration for emergency use authorization of its COVID-19 vaccine for kids ages 6 months to 5 years old.

The FDA will now review the data, bring it before its expert advisers and potentially authorize the vaccine in the coming weeks before sending it to the Centers for Disease Control and Prevention for final approval.

“Ultimately, we believe that three doses of the vaccine will be needed for children 6 months through 4 years of age to achieve high levels of protection against current and potential future variants,” Pfizer CEO Albert Bourla said in a statement. “If two doses are authorized, parents will have the opportunity to begin a COVID-19 vaccination series for their children while awaiting potential authorization of a third dose.”

Here are nine questions answered about the COVID-19 vaccines and kids as families seek to make the best decisions.

1. What is the science behind the COVID-19 vaccine?

Both the Pfizer and Moderna vaccines use mRNA technology, which does not enter the nucleus of the cells and doesn’t alter human DNA. Instead, it sends a genetic “instruction manual” that prompts cells to create proteins that look like the outside of the virus — a way for the body to learn and develop defenses against future infection.

The Johnson & Johnson vaccine uses an inactivated adenovirus vector, Ad26, that cannot replicate. The Ad26 vector carries a piece of DNA with instructions to make the SARS-CoV-2 spike protein that triggers an immune response.

This same type of vaccine has been authorized for Ebola and has been studied extensively for other illnesses and for how it affects women who are pregnant or breastfeeding.

Neither of these vaccine platforms can cause COVID-19.

2. What is the status of vaccine eligibility for kids?

Children ages 5 and older are now eligible to receive Pfizer’s two-dose vaccine.

Children ages 12 to 15 are also eligible to receive a Pfizer vaccine booster shot.

Pfizer has submitted data to the FDA for a two-dose vaccine for kids under five, with the expectation that data will soon be available to make it a three-dose vaccine, which will likely be more effective. The company announced in December that it would amend its ongoing clinical trials for children under age 5 to add a third dose.

The two other vaccines currently available in the U.S., Moderna and Johnson & Johnson, are currently available only for people 18 years and older.

Moderna filed for emergency use authorization with the FDA for its vaccine in adolescents in June but is still awaiting a decision.

Johnson & Johnson announced in April that it had begun vaccinating a “small number of adolescents aged 16-17 years” in a Phase 2a clinical trial.

As of April, the trial was enrolling participants only in Spain and the United Kingdom, with plans to expand enrollment to the U.S., the Netherlands and Canada, followed by Brazil and Argentina.

3. Why do kids need to be vaccinated against COVID-19?

While there have not been as many deaths from COVID-19 among children as adults, particularly adults in high-risk categories, kids can still get the virus and they can also transmit the virus to adults.

A total of 11.4 million children have tested positive for the virus since the onset of the pandemic. Child COVID-19 cases have “spiked dramatically” during the omicron variant surge, with more than 3.5 million child cases reported in January.

According to the CDC, unvaccinated 12- to 17-year-olds had an 11 times higher risk of hospitalization than fully vaccinated adolescents.

“We know that COVID does not spare kids,” ABC News medical contributor Dr. John Brownstein, an epidemiologist and chief innovation officer at Boston Children’s Hospital, said in December. “Maybe it’s less severe than their adult counterparts but we also know that the virus has had real significant impacts on morbidity and mortality in kids.”

“We also know that kids play an important role as vectors of spread,” he said. “And especially in light of increases we’re seeing right now, with increases of cases in kids in record numbers, infections among kids further perpetuate community transmission and further create risks for those who would be the most vulnerable of the virus.”

4. Do kids experience the same vaccine side effects as adults?

Adolescents experienced a similar range of side effects to Pfizer’s vaccine as seen in older teens and young adults — generally seen as cold-like symptoms in the two to three days after the second dose — and had an “excellent safety profile,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said in August.

None of the children in Pfizer’s clinical trials of kids ages 5-11 experienced a rare heart inflammation side effect known as myocarditis, which has been associated with the mRNA vaccines in very rare cases, mostly among young men.

5. Is there data showing COVID-19 vaccines are safe for kids?

The CDC released three studies in December showing COVID-19 vaccines are safe and effective for children.

One study, which evaluated the safety reports of more than 42,000 children ages 5 to 11 who received a Pfizer shot, found the side effects from the Pfizer vaccine were mostly mild and temporary. It also found that myocarditis, a heart inflammation side effect that has been associated with the mRNA vaccines in very rare cases, does not appear to be a risk.

A second study, which looked at data from 243 children ages 12 to 17 in Arizona, found the Pfizer vaccine was 92% effective at preventing infection. The study, conducted between July and December when delta was the dominant variant in the U.S., also found that adolescents who developed COVID-19 reported a lower percentage of time masked in school and time masked in the community.

The third study, also conducted when delta was dominant, found that among children ages 5 to 17 hospitalized due to COVID-19, less than 1% were fully vaccinated against the virus.

6. How effective are the vaccines in children?

Pfizer announced in late March that its clinical trials showed the vaccine was safe and 100% effective in children ages 12-15, similar to the 95% efficacy among adult clinical trial participants.

Marks confirmed on May 10 that after a trial with more than 2,000 children, Pfizer found no cases of infection among the children who had been given the vaccine and 16 cases of infection among the children who received a placebo.

No cases of COVID occurred in the 1,005 adolescents that received the vaccine, while there were 16 cases of COVID among the 978 kids who received the placebo, “thus indicating the vaccine was 100% effective in preventing COVID-19 In this trial,” said Marks.

7. Do kids get the same dose of the vaccines as adults?

In Pfizer’s clinical trial, children between 6 months and 5-years-old received two doses of 3-microgram shots, a tenth of the dose given to adults, three weeks apart.

Kids ages 5 to 11 are given a 10-micrograms dose of the Pfizer vaccine, one-third of the adolescent and adult dose. Like with adults and adolescents, the pediatric vaccine is delivered in two doses, three weeks apart.

For 12-to-15-year-olds, the FDA has authorized the same dosing as adults with the Pfizer two-dose vaccine.

The FDA and CDC have recommended the Pfizer booster shots now available for kids ages 12 and older be administered five months after the primary vaccine series.

8. Could COVID-19 vaccines impact puberty and menstruation?

There is currently no clinical evidence to suggest any of the COVID-19 vaccines can have long-term effects on puberty or fertility.

9. Where can kids get vaccinated against COVID-19?

Vaccines are accessible at pediatricians’ offices, children’s hospitals, pharmacies like CVS, Walgreens and Rite-Aid and school and community-based clinics.

Parents can search for appointments at Vaccines.gov to find a local provider.

ABC News’ Sasha Pezenik, Anne Flaherty, Eric Strauss, Cheyenne Haslett and Jade A. Cobern, MD, a member of the ABC News Medical Unit, contributed to this report.

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