Pfizer’s Third Covid Shot Boosts Antibodies in Kids 5 to 11 (1)

Pfizer Inc. and BioNTech SE said a third dose of their Covid vaccine increased antibodies against the omicron strain by 36-fold in a clinical trial in younger school-aged kids.

The companies plan to file for emergency-use authorization in the U.S. in the coming days based on the results, according to a statement Thursday. They will also submit the data to other regulators around the world.

In the trial, 140 kids ages 5 to 11 were given a third shot of a 10 microgram dose of the vaccine about six months after their second dose. A month later, antibodies against the ...