Pfizer says it's time for a Covid booster; FDA and CDC say not so fast
(CNN)Drugmaker Pfizer said Thursday it is seeing waning immunity from its coronavirus vaccine and says it is picking up its efforts to develop a booster dose that will protect people from variants.
Pfizer says it's time for a Covid booster; FDA and CDC say not so fast
Pfizer says it is seeing waning immunity from its coronavirus vaccine and says it is picking up its efforts to develop a booster dose that will protect people from variants.




