Pfizer Inc. and the maker of the other leading US vaccine candidate, Moderna Inc., have been cautioning for weeks that the earliest they could seek regulatory approval for wider use of their shots would be late November.In Britain, AstraZeneca recently said it hoped to prove its own vaccine was effective by year's end.Late on Monday in a series of tweets President Donald Trump accused the US Food and Drug Administration and Pfizer of waiting until after the election to announce its positive vaccine news.
Pfizer did not receive data from independent trial monitors until Sunday, however, and the FDA was not involved in Pfizer's decision to announce its early results.The hard truth: Science moves at its own pace.