What’s ahead for COVID-19 vaccines

Pfizer's surprising news that its COVID-19 vaccine might offer more protection than anticipated — an announcement right after a fraught U.S. presidential election campaign — is raising questions about exactly how the different shots will make it to market.

Pfizer Inc. and the maker of the other leading U.S. 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.