World Health Organization calls new COVID strain a "variant of concern"

A new strain of coronavirus is a "variant of concern," the World Health Organization announced Friday. The strain, now named Omicron, was reported to the agency by South Africa on Wednesday.

Omicron, initially known as B.1.1.529, has a large number of mutations and may be more likely to reinfect people, according to a release from the agency. A strain is deemed a variant of concern when it has genetic changes that increase its transmissibility or virulence or decrease the efficacy of treatments and other health measures.

The variant first appeared in a specimen collected November 9.