The Food and Drug Administration said Sunday that Pfizer's COVID-19 vaccine appears to be safe for children under 5 years old, the only age group not yet eligible for vaccination in the U.S.
The agency published its review ahead of a Wednesday meeting in which outside experts will vote on whether the vaccine is ready for the nation’s youngest population.
The FDA posted a similar analysis last week of Moderna’s vaccine for children under the age of 6.
Vaccinations could begin as soon as next week if regulators clear shots by one or both drug manufacturing companies.
According to the FDA's review, COVID-19 hospitalizations and deaths for children 6 months to 4 years old are higher than for children in other age groups despite the babies, toddlers and preschoolers only making up about 3% of cases in the U.S.
The agency said children who received Pfizer’s shots during clinical trials developed high levels of virus-fighting antibodies expected to offer protection against COVID-19, the basic threshold required for authorization from the FDA.
Pfizer’s vaccine was given in three doses and appeared 80% effective in preventing symptomatic COVID-19. However, that data was based on just 10 cases diagnosed among study participants and could change as Pfizer’s study continues.
Meanwhile, Moderna’s two-dose vaccine was only about 40% to 50% effective at preventing milder infections.
The two companies' vaccines were tested at different points during the pandemic, with different variants circulating at the time of each study. Moderna has started testing a booster shot for toddlers.
The FDA on Wednesday will ask an independent panel of vaccine experts to debate the data from both companies prior to voting, although the agency is not required to make a decision based on the group’s recommendations.
An official decision is expected to be made shortly after Wednesday’s meeting. Then, the Centers for Disease Control and Prevention will host its own panel of experts to debate which toddlers need COVID-19 vaccinations.
For the youngest children, each drug company is offering different dose sizes and number of shots. Pfizer's vaccines will be available for kids 6 months through 4 years and Moderna's extends through 5 years old.
Pfizer and its partner BioNTech are expected to offer two doses three weeks apart and a third at least two months later. Each shot will be one-tenth the dose administered to adults. Pfizer is the only company that currently has a COVID-19 vaccine designed for older children in the U.S.
Moderna's vaccine would include two shots given about four weeks apart, each a quarter of the company's adult dose.
More than 30,000 U.S. children under 5 years old have been hospitalized with the virus and nearly 500 COVID-19 deaths have been reported in the same age demographic, according to U.S. health officials.
The federal government has allowed pharmacies and states to begin placing orders for the vaccines for young children last week. There are 5 million doses initially available, with each company producing half the shots.
Despite the potential FDA authorization for the vaccines, demand for the shots is expected to be fairly low. A recent survey suggests only 1 in 5 parents of young children would have their kids receive the vaccine right away. Vaccines have been available for older U.S. children since November, but less than a third of kids ages 5 to 11 have been administered the two recommended doses, government data shows.
The Associated Press contributed to this report.