BREAKING NEWS

Omicron is now the most common variant among new Covid cases in the U.S., accounting for nearly three-quarters of new infections, the C.D.C. said.

Monday, December 20, 2021 6:54 PM EST

Omicron, discovered thanks to its distinctive combination of more than 50 mutations, has turned out to be highly transmissible — two to three times as likely to spread as Delta — and less susceptible to vaccines than other variants. Early cases raised hopes that it may cause milder disease than other variants, but scientists say more research is needed.

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