What does full approval of Pfizer’s COVID-19 vaccine mean?

Pfizer’s COVID-19 vaccine has been given the Food and Drug Administration’s full approval, meaning it has now undergone the same rigorous regulatory review as dozens of other established vaccines. COVID-19 vaccines in the U.S. were initially rolled out under emergency use authorization, which lets the FDA speed the availability of medical products in public health emergencies. The vaccines underwent testing in tens of thousands of people to establish safety and effectiveness. But the FDA initially required only about two months of safety monitoring data, the period when side effects are most likely to occur. For full approval, the FDA required six months of data, among other things.