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Bay Area Expert Says a Quarter of Americans With Omicron May Be Asymptomatic

SAN JOSE (KPIX) -- An average of one in four Americans could be infected with COVID-19 and not know it, according to a Bay Area medical expert who said the prediction is based on South Africa's experience with the omicron surge.

"It's estimated that there's a higher proportion of people who don't even know they're infected with omicron compared to alpha and delta and some of the other variants," said UCSF infectious disease specialist Dr. Peter Chin-Hong.

The examples of South Africa and the East Coast, which were hit with a massive wave of the omicron variant before California, have been used to model predictions for the surge we're now experiencing in the Golden State.

Dr. Chin-Hong said the United States could have an even higher percentage of the population unknowingly infected with the virus compared to South Africa, because Americans are more vaccinated and boosted.

The reason? The immunizations have been resulting in mild to no symptoms for many people recently, which is likely fueling the surge as people gather, without being tested or testing too late, Dr. Chin-Hong said.

"We're programmed to look at somebody or hear somebody cough, move away from them but, when they're not coughing or asymptomatic, we might let our guard down," Dr. Chin-Hong said. "You may have such mild symptoms that they go away very quickly before you even think about getting tested."

London Stiger, a Concord cosmetology student and part-time nanny, just completed quarantine Wednesday after she and her mother tested positive for COVID-19 around New Year's Day.

She said she took every precaution advised by the CDC, including getting vaccinated. Stiger said they even avoided family gatherings over the holidays.

"It was a surprise when we got it," Stiger said.

The symptoms were mild and, because of that, she said she now knows why some may brush it off as no big deal.

"Felt like a sore throat, like a cold," Stiger said. "When I started getting my symptoms I was telling my mom I could be sick, could just be a cold."

Dr. Chin-Hong warns that people should assume everyone is infected even if they don't look like they are.

Stiger agrees that a significant percentage of people predicted to get sick won't know it.

"You never know, especially for those people who are asymptomatic," Stiger said. "So I think everybody should just be cautious."

There is, however, a positive prediction.

Dr. Chin-Hong said a dip in the virus' RNA was discovered in Santa Clara County's waste water Thursday. The doctor said that means it could be a sign there will be a decline in COVID-19 cases around the end of January.

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