New variant of virus showing up in rising numbers.

Health officials studying strain, unclear if it is more contagious than better known one

A new variant of the COVID-19 virus is appearing in a rapidly increasing number of cases, causing public health officials concern both in Santa Clara County and across California. Officials from the state Department of Public Health, Santa Clara County and UC San Francisco announced Sunday that the variant has been found in recent outbreaks in the South Bay.

“These outbreaks are associated with a very high attack rate, meaning many of these individuals who became exposed were infected,” said Dr. Charles Chiu, a virologist and professor of laboratory medicine at the UC San Francisco. “We’re talking 80 and 90 percent of all the residents in the hospital became infected.”

Chiu said in an interview Sunday night that the first case of the variant in California was discovered in May in Alameda County. But from mid-November to the last two weeks of December the cases went from numbering 3.8% of all COVID-19 cases to 25%.

“It’s too soon to know if this variant will spread more rapidly than others,” Dr. Erica Pan, an epidemiologist for the California Department of Public Health, said in a statement.

News of another variant of COVID-19 came just as officials grapple with high rates of cases, limited ICU beds and a slow rollout of the two vaccines for the virus. “The fact that this variant was identified in several large outbreaks in our county is a red flag and must be investigated further,” Santa Clara County Health Officer Dr. Sara Cody said in a statement. “This virus continues to mutate and adapt, and we cannot let down our guard.”

Neither Cody nor other officials were immediately available to discuss whether the variant could specifically be linked to recent outbreaks at a Kaiser Permanente facility in San Jose, on the SJSU football team, and at Santa Clara County jails. In his interview, Chiu declined to specifically name any outbreaks, other than saying the ones described to him were “health care-associated.”