Vaccine maker Pfizer said Friday that trials of its vaccine in children ages 2 to 5 show that it did not provide the expected immunity in kids this age, and it is adding a third dose to the regimen.

This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated. Pfizer said Friday it was changing plans and ...

U.S. health authorities again expanded the nation's booster campaign Thursday, opening extra doses of Pfizer's COVID-19 vaccine to several million 16- and 17-year-olds. The U.S. and many other nations ...

A third dose of the Pfizer/BioNTech COVID-19 vaccine can "strongly" boost protection against the delta variant -- beyond the protection afforded by the standard two doses, suggests new data released ...

NEW YORK, N.Y. — Pfizer announced Wednesday that data shows a third dose of its COVID-19 vaccine can “strongly” boost protection against the highly transmissible delta variant. The pharmaceutical and ...