By now you’ve probably heard that Pfizer’s Covid-19 vaccine has received full approval from the FDA. Initially, the FDA waived some of its usual requirements for emergency approval. Pfizer's shot for people 16 and older has now undergone the same rigorous testing and regulatory review as dozens of other long-established vaccines.

For full approval, the FDA required six months of follow-up data. FDA inspectors also visited the plants where the vaccines are made and reviewed each step of the production process for extra assurance that the shots are made under safe, sterile conditions.

The status...