What’s Ahead For Virus Vaccines?

Pfizer’s surprising news that its COVID-19 vaccine might offer more protection than anticipated is raising questions about exactly how the different shots will make it to market. Pfizer and the maker of the other leading U.S. vaccine candidate have been cautioning for weeks that the earliest they could seek regulatory approval for wider use of their shots would be late November. Science moves at its own pace. COVID-19 vaccines worldwide are being developed at record speeds in hope of ending the pandemic. And when they’re ready for prime time depends on a long list of research steps including how many study volunteers wind up getting the coronavirus.