WASHINGTON (AP) — A person in San Francisco is the first in the U.S. to have an identified case of the omicron variant of COVID-19, the Centers for Disease Control and Prevention confirmed Wednesday.
The person had recently traveled to South Africa and had returned on Nov. 22, the CDC said.
“The individual, who was fully vaccinated and had mild symptoms that are improving, is self-quarantining and has been since testing positive,” a news release from the agency reads. “All close contacts have been contacted and have tested negative.”
The California Department of Public Health also shared the news Wednesday, crediting researchers at UC San Francisco for identifying the case through sequencing.
The case in California comes as scientists continue to study the risks posed by the new strain of the virus.
The Biden administration moved late last month to restrict travel from Southern Africa where the variant was first identified and had been widespread. Clusters of cases have also been identified in about two dozen other nations. The official could not discuss the matter publicly and spoke to the AP on condition of anonymity.
The Centers for Disease Control and Prevention is taking steps to tighten U.S. testing rules for travelers from overseas, including requiring a test for all travelers within a day of boarding a flight to the U.S. regardless of vaccination status. It was also considering mandating post-arrival testing.
Officials said those measures would only “buy time” for the country to learn more about the new variant and to take appropriate precautions, but that given its transmissibility its arrival in the U.S. was inevitable.
Much remains unknown about the new variant, including whether it is more contagious than previous strains, whether it makes people more seriously ill, and whether it can thwart the vaccine. Dr. Anthony Fauci, the top U.S. infectious disease expert, said more would be known about the omicron strain in two to four weeks as scientists grow and test lab samples of the virus.
The announcement of the first U.S. case comes before President Joe Biden plans to outline his strategy on Thursday to combat the virus over the winter. Biden has tried to quell alarm over the omicron variant, saying it was a cause for concern but “not a cause for panic.”
Biden and public health officials have grown more urgent in their pleas for more Americans to get vaccinated — and for those who have been vaccinated to get booster shots to maximize their protection against the virus.