Pfizer Says Covid-19 Vaccine Safe and Effective for Kids Ages 5 to 11

FDA authorization could come as early as October

A diverse group of masked children sit at the top of a slide at a park
Children ages 5 to 11 could be eligible to get the vaccination as early as October, pending FDA authorization. kali9 via Getty Images

Pfizer-BioNTech announced yesterday morning that their Covid-19 vaccine has been shown to be safe and highly effective in children 5 to 11 years old. If the federal regulatory review process for the vaccine follows a similar timeline as it did for adults—about a month—millions of kids could be eligible to receive their first dose around Halloween.

“There’s going to be a huge number of parents who are going to heave a big sigh of relief when they hear this,” says Mount Sinai pediatrician and vaccine expert Kristin Oliver to Apoorva Mandavilli for the New York Times. “We’ve been waiting for these kids to be protected.”

Children now account for more than one in five new cases, and the highly transmissible Delta variant and re-opening of schools this fall has contributed to the recent surge in infections. Children in states with the lowest adult vaccination rates have seen the most cases, and almost 30,000 children were hospitalized for Covid-19 in August, according to the New York Times. Pfizer and BioNTech aim to apply for FDA emergency use authorization for the shot's use in elementary-school-age kids by the end of the month.

"Since July, pediatric cases of Covid-19 have risen by about 240 percent in the U.S.,” said Albert Bourla, the chairman and CEO for Pfizer, in a statement. “These trial results provide a strong foundation for seeking authorization of our vaccine for children 5 to 11 years old, and we plan to submit them to the FDA and other regulators with urgency.”

Pfizer’s latest trial, which hasn’t yet been peer-reviewed, included more than 2,000 children ages 5 to 11. Two-thirds of the youngsters received two doses of the vaccine three weeks apart, and the remaining third received a saltwater placebo. To assess the vaccine’s protection, scientists measured the children’s antibody response. Elementary-aged children were given one-third of the vaccine dose that older kids and adults received, but mounted a similar immune response. At higher doses, researchers found kids had more side effects, like fevers and headaches, though none were severe. Kids received just 10 micrograms, rather than the 30 microgram dose used for people 12 and older, reports Jaclyn Diaz for NPR.

“You want to hit the sweet spot, where you’re giving the lowest dose that might elicit reactions, but also high enough to get you a good, sustainable antibody response,” says Yvonne Maldonado, a pediatrician led the trial at Stanford University, to the New York Times. For trials in kids under 5, a tenth of the adult dose—3 micrograms—is being used and appears effective, says Maldonado, who also chairs the American Academy of Pediatrics’ infectious disease committee.

A spokesperson from Pfizer also confirmed that they found no instances of a type of heart inflammation called myocarditis in their trial, which has been linked in rare cases to mRNA vaccines, according to CNN’s Amanda Sealy. If authorized, an additional 28 million people will be eligible to be vaccinated against Covid-19.

Like the process for seeking emergency authorization for the vaccine in teens and adults, FDA scientists must first review trial data to look for any safety concerns or other errors. The company’s vaccine trial data for kids younger than five aren’t expected until the end of the year at the earliest, according to Pfizer officials. Results from Moderna’s vaccine trial data for children under 12 is also expected to be released around the same time.