Vaccine Makers Preparing for Mutant Coronavirus Strains (1)

Drugmakers who designed the first Covid-19 vaccine to gain clearance from Western regulators say they could reset the shot to counter a new strain within just six weeks, if needed.

BioNTech SE Chief Executive Officer Ugur Sahin said he’s confident that the inoculation his company developed with Pfizer Inc. will work just fine against the fast-spreading coronavirus variant that’s raising alarms in the U.K. and beyond. If the current shot fails to be adequately protective, though, the company could tweak it by updating small bits of genetic information called messenger RNA that their vaccine uses.

“The beauty of the messenger ...