Authorities identified five mildly symptomatic COVID-19 cases involving the Omicron variant in Alameda County, public health officials announced Friday.
The patients are among 12 coronavirus cases in the area traced to a Nov. 27 wedding in Wisconsin, which one of the patients attended after traveling abroad, according to the Alameda County Public Health Department.
A state lab used genomic sequencing to identify the five Omicron variant cases, but officials said such testing was not yet available for the remaining seven coronavirus cases.
The patients are between the ages of 18 and 49, officials said. One person is a Berkeley resident; the remaining 11 are county residents.
All 12 people were vaccinated and most had received boosters, officials said. None was hospitalized.
Public health officials are notifying those who've been in close contact with the patients and providing isolation and quarantine guidance, authorities said.
"We don’t yet know how Omicron will impact a highly vaccinated region like the Bay Area," the Public Health Department said in a statement. "We remind residents that vaccination continues to provide the best protection against severe illness from COVID-19 that could result in hospitalization and death."
Officials continue to advise the public to get vaccinated, including booster shots if eligible; stay home if sick; wear a mask indoors; wash their hands; avoid crowds and poorly ventilated indoor settings; and get tested before and after any gatherings or travel, or if exposed to a positive case.
The disclosure came on the same day that San Diego County reported an uptick in coronavirus cases that health officials suspect is a result of Thanksgiving gatherings.
The San Diego County Health and Human Services Agency reported 1,153 cases on Thursday, up from counts in the 600s over the previous two days, officials said in a statement.
The uptick in cases is not believed to be due to the Omicron variant, which hasn’t been identified in San Diego County.
"The last time more than 1,150 cases were reported was Sept. 10, when 1,188 cases were identified," officials said.
Dr. Cameron Kaiser, a county deputy public health officer, said he suspected more increases in coronavirus cases will probably occur in the coming months because of holiday gatherings.
"Unfortunately, rises like these after holidays are not unexpected," Kaiser said in a statement. "We are vigilant for any changes in cases that Omicron might cause, but we’ve seen similar spikes like this in the past."
Omicron has also been detected in recent travelers who live in Los Angeles County and San Francisco. Both were vaccinated, and neither person needed to be hospitalized.
This story originally appeared in Los Angeles Times.