Pfizer Urged to Wait for November to Seek Vaccine Authorization

Pfizer Inc. should wait until at least late November before seeking FDA authorization of its Covid-19 vaccine to meet rigorous safety standards, more than 60 leading researchers and bioethicists said.

The letter, obtained by Bloomberg Law and verified by six signatories, was sent Friday following reports that Pfizer’s clinical trial will yield conclusive results in October. That would likely put the company ahead of Moderna Inc. and AstraZeneca PLC and other promising vaccine candidates.

But the researchers said Pfizer’s clinical trial needs to monitor participants for at least two months after they received the second dose. That would bring...