Vaccine makers move quickly against new omicron Covid variant, testing already under way

The world’s major manufacturers of Covid-19 vaccines said Friday that they are working to quickly investigate and adapt their shots to a new and highly mutated strain of the virus.

The World Health Organization on Friday said the new strain, named omicron, is a “variant of concern” that may pose a higher risk of reinfection than past mutations of the virus.

Pfizer and BioNTech said they are investigating omicron, first labeled B.1.1.529, and can adapt their vaccine quickly if needed.

“We understand the concern of experts and have immediately initiated investigations on variant...