https://apnews.com/33e81ee1daddd9ff04c136db620aa1ae > U.S. regulators on Tuesday authorized another COVID-19 booster for people age 50 and older, a step to offer extra protection for the most vulnerable in case the coronavirus rebounds. > The Food and Drug Administration's decision opens a fourth dose of the Pfizer or Moderna vaccines to that age group at least four months after their previous booster.