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California Gov. Gavin Newsom (D) announced on Wednesday that a new variant of the coronavirus believed to be much more contagious has been found in California.

The variant, first identified in Britain, was discovered in Southern California, Newsom said, without naming a specific city. The first known U.S. case of COVID-19 caused by the variant was reported in Colorado on Tuesday.

During a conversation with Newsom, Dr. Anthony Fauci, the nation's top infectious disease expert, said that while it appears the strain is significantly more contagious, "there's no indication at all that it increases the virulence ... the ability to make you sick or kill you. It doesn't seem to make it more strong in that regard." He also said it looks like the COVID-19 vaccines now being used are effective against the new variant.

The variant was first detected in southeast England, and the Los Angeles Times reports that some scientists believe the strain might have spread quickly through the region not due to genetic changes, but because it went through dense communities and infected people who were less likely to wear masks and socially distance.