Health officials say the patient, a man in his 20s with no travel history, is recovering in isolation.
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"To our knowledge, it does not seem to be associated with worse disease than the more common strain," said UCSF infectious disease doctor, Mike Reid, who runs San Francisco's contact tracing program.
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"We haven't seen any of this strain in San Francisco, that may change over time," said Dr. Reid, who says the real burden is now on labs, which will need to sequence more samples, in order to track the new variant strain.
"They will start by doing that additional genetic sequencing on strains from individuals that maybe have traveled from the UK and are now symptomatic, or individuals that are symptomatic and have COVID and have been exposed to somebody from the UK."
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"It bears watching to track variants, because some of them can develop more and more mutations," Dr. Reid said.
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Stanford epidemiologist, Dr. Yvonne Maldonado, says there have been many COVID-19 variants. The concern with the UK variant is the eight mutations on the spike protein - the basis for immunity.
"Everyone is watching that protein like a hawk," said Dr. Maldonado, who questioned, "Will there be escape mutants that escape the immunity?"
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Dr. Maldonado says Pfizer and Moderna are tracking the variants and if they detect that a piece of the virus is no longer susceptible to their vaccines, they can tweak them in a matter of months.
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"What you can do is you can change the RNA of the vaccine to match the new mutation, and then make antibodies to the mutation as well, so they can do that. We do that with the flu vaccine every year."
Meanwhile, staying masked and distanced is more important than ever.
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