U.S. FDA authorizes 4th dose of Pfizer COVID-19 shot for Americans 50 and up

U.S. regulators have authorized a fourth dose of Pfizer-BioNTech's COVID-19 vaccine for Americans 50 and older because of concerns about waning immunity in the age group, the drugmakers said on Tuesday.

source https://www.cbc.ca/news/health/fourth-dose-covic-vaccine-pfizer-1.6401036?cmp=rss