The Pfizer COVID-19 vaccine is nearly 91% effective against symptomatic illness in children ages 5-11, according to new data posted Friday ahead of a major FDA advisory committee meeting on Tuesday.
The vaccine also appeared safe, with none of the children experiencing a rare heart inflammation side effect known as myocarditis. If authorized in children 5-11, the Pfizer vaccine will be given at a smaller, one-third dose.
This efficacy estimate is from the company's clinical trial of 2,268 children in which some children got a placebo, and some children got the Pfizer vaccine. During the trial, 16 children who got the placebo shots developed COVID-19. Only three children who got the real vaccine developed COVID-19.
A small number of the children who were vaccinated and later developed COVID-19 experienced symptoms far fewer and milder than the children who were unvaccinated. For example, none of the vaccinated children developed a fever, while a majority of the unvaccinated children developed a fever along with other symptoms.
None of the children experienced serious adverse events. Many experienced typical symptoms like pain at the injection site, fatigue and headache.
The FDA's advisers will meet Tuesday to vote on whether to authorize the vaccine. From there, the FDA itself and the CDC will need to sign off -- a process that can take several days -- before shots could become available to children nationally.
- ABC News' Sony Salzman