U.S. to Clear Additional Booster Shot Against Covid-19

The U.S. Food and Drug Administration is poised to clear a fourth dose of the mRNA coronavirus vaccine for adults age 50 and older, looking to shore up protections for more vulnerable groups, a person familiar with the matter said.

The authorization could come as early as next week and, for most Americans, it would mean a second booster shot of either the Pfizer-BioNTech or Moderna vaccines. Currently, only immunocompromised people are eligible in the U.S. for the additional dose.

Unlike with previous authorizations, the FDA is expected to stop short of a full recommendation, meaning the option would be ...