According to officials, the COVID-19 variant first seen in the UK, has been detected in a man in his 30s who lives in San Diego County and began showing symptoms on Dec. 27. He was tested on Dec. 29.
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"Because there is no travel history, we believe this is not an isolated case in San Diego County," said San Diego County supervisor, Nathan Fletcher.
"There is significant evidence that it does spread considerably faster," Fletcher said.
Colorado health officials say one case, and a suspected second case of the variant, were found in National Guard members deployed to a nursing home outside Denver.
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Governor Newsom hosted a virtual conversation with Dr. Anthony Fauci and discussed the variant.
"I don't think that Californians should feel this is something odd. This is something that's expected," said Dr. Fauci, who said this about the variant: "There's no indication at all that it increases the virulence, and by virulence I mean the ability to make you sick or kill you."
Shannon Bennett is the chief of science at California Academy of Sciences in San Francisco. She's a virologist specializing in viruses that emerge from non-human animals - like coronavirus.
She explained why the variant may be spreading faster than the viruses we've seen before.
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"There are mutations for this variant in many parts of the whole spike protein and some of them, the ones on the receptor-binding domain, are likely to increase the stickiness, but the ones that are in the fusion domain might increase it's efficiency to fuse with the host cell membrane and enter the host cell."
The good news according to Bennett, "for SARS-CoV-2 it's evolving more slowly than influenza or flu, so that means it's a slower moving target and the vaccine technologies that we're applying here, the two mRNA vaccines, are more adjustable than the influenza or flu vaccine technologies."
On Tuesday, Stanford epidemiologist, Dr. Yvonne Maldonado, explained what Pfizer and Moderna are doing to monitor the mutations.