Starting later this week, some at-risk Americans become eligible for a 4th Covid shot.
Some people with a weakened immune system can get a fourth dose of the coronavirus vaccine as early as this coming week, according to recommendations from the Centers for Disease Control and Prevention that were updated last week. The C.D.C. endorsed a third dose of the Pfizer-BioNTech and Moderna vaccines for moderately or severely immunocompromised…