First U.S. omicron case present in San Francisco. Right here’s what we all know

A case of the variant Omicron coronavirus has been identified in San Francisco – the first in the country, officials said on Wednesday.

The case was discovered in someone who traveled to the United States from South Africa on November 22 and tested positive for COVID-19 on Monday, said Dr. Anthony Fauci during a White House briefing.

That person was fully vaccinated and in self-quarantine, the country’s leading infectious disease expert said, adding that he had “mild symptoms” that were improving by the time. He didn’t know if they’d received a booster.

All close contacts with the person were contacted and tested negative, according to a joint statement from the San Francisco and California health authorities and the US Centers for Disease Control and Prevention.

The variant was discovered through genomic sequencing at UCSF, Fauci said.

“California’s large-scale testing and early detection systems have found the omicron COVID-19 variant in California,” tweeted Governor Gavin Newsom. “We should assume that it is in other states as well. There is no need to panic – but we should stay vigilant. That means getting vaccinated. Let yourself be strengthened. Wear a mask indoors. “

The variant known as B.1.1.529 is raising alarms worldwide due to its potential for increased transferability and vaccine avoidance, even if much is unknown about it, including the risk of infection.

Public health officials have feared that new variants could pose a threat to the United States’ ability to end the pandemic quickly, either by bypassing vaccines or spreading too quickly to contain it. New variants could lead to more illnesses and deaths if they cause more severe symptoms or are more contagious and possibly trigger new surges.

SFO is one of four U.S. airports – along with Atlanta, JFK, and Newark – that is expanding testing at terminals, said CDC director Dr. Rochelle Walensky on Tuesday.

Health authorities are urging people to continue taking the known protective measures until scientists better understand whether and how great the threat from the variant is.

“That shouldn’t be a cause for panic. It shouldn’t be a reason to go without vaccines, ”said Peter Chin-Hong, an infectious disease specialist at UCSF, before the variant was discovered in San Francisco. “This should be a reason to get vaccines and booster vaccines. These are the people who are protected. “

The World Health Organization (WHO) said Monday that early evidence suggests the risk of Omicron is “very high” and that overvoltages with “serious consequences” are possible.

The variant was first identified in South Africa, a country with a robust genome surveillance program, and several cases have since been discovered in other countries.

It is unknown if Omicron can defeat the Delta variant of the virus, which is the dominant strain in the United States.

“Although much is still unknown about the Omicron variant, we know that you can take steps to protect yourself and your family from all variants of COVID-19: Get vaccinated, wear a mask, get tested and stay home if you’re “sick,” said Leah Greenbaum, emergency services coordinator for Napa County, ahead of Wednesday. “We are closely monitoring developments and are focusing on our COVID-19 vaccination and booster efforts.”

Omicron has 32 mutations on the spike protein – a critical place where the virus attaches to human cells – and at least 14 of those mutations have been found in other variants. Delta has nine mutations on the spike protein, five of which are shared with other variants.

Doctors in South Africa report that patients so far have mostly had mild symptoms, but many of them are young adults who generally do not get as sick of COVID-19 as older patients.

“Just like the first case of COVID that was discovered on the Grand Princess cruise ship that was held in the bay, it’s a metaphor that the virus doesn’t respect borders and we need to be constantly vigilant but not indulge in demeaning.” Fear, ”said Chin-Hong.

This story will be updated.

The Chronicle’s author, Catherine Ho, contributed to this report.

Aidin Vaziri and Erin Allday are contributors to the San Francisco Chronicle. Email: avaziri@sfchronicle.com eallday@sfchronicle.com