U.S. FDA authorizes 4th dose of Pfizer COVID-19 shot for Americans 50 and up
US 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. The US Food and Drug Administration also authorized this additional booster of the vaccine for people aged 12 and older with compromised immune systems. … Read more