The US has its first omicron case—and the patient was fully vaccinated

Omicron is officially in the US.
Omicron is officially in the US.
Image: Reuters/Tom Brenner
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The covid-19 omicron variant is officially circulating in the US. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, said today (Dec. 1) US officials confirmed the first case of covid-19 caused by the omicron variant, which was first reported in southern Africa last week.

The person tested positive for the omicron variant on Nov. 29 in California, a week after returning from a trip in South Africa. Fauci said at a White House news conference the patient was self-quarantining and had been fully vaccinated for covid-19, but that he did not believe the person had received a booster. None of the patient’s close contacts have tested positive, according to Fauci. Officials in Nigeria and Ghana reported the first confirmed omicron cases in their countries today as well.

“We knew it was just a matter of time before before the first case of omicron would be detected in the United States,” Fauci said. He stressed it was too early to draw any conclusions about the variant from this single patient, whose symptoms appear to be improving. Fauci said he expects to have more information about transmission and the severity of the disease in the next two to three weeks.

Fauci stresses recommendation for covid-19 booster

Nearly 60% the US population has been fully vaccinated for covid-19, according to Our World in Data, while some 12% of Americans have received booster shots. The Centers for Disease Control and Prevention has recommended all adult recipients of the Pfizer or Moderna vaccines get a booster six months after their second dose, while Johnson & Johnson recipients should get a booster two months after their dose.

Fauci explained that a booster may provide effective protection against the omicron variant. Neutralizing antibodies that help prevent and treat covid-19 go “way up” after an individual receives a booster shot, he said, and that can provide protection against a number of different variants. This has been the case for the delta variant.

“Our experience with variants such as the delta variant is that even though the vaccine isn’t specifically targeted to the delta variant, when you get a high enough level of an immune response, you get spillover protection even against a variant that the vaccine wasn’t specifically directed at,” Fauci said. Research indicates Pfizer and Moderna are 96% effective at preventing severe disease from the delta variant, while J&J is 85% effective.

Fauci said health officials have “every reason to believe” the antibody response provided by current vaccines should be helpful in preventing severe disease caused by omicron, but there’s not enough data to know for sure yet. Vaccine makers are working to assess the effectiveness of their shots and have said they’re prepared to modify them to protect against the omicron variant if need be.

In the meantime, Fauci stressed that getting a covid-19 booster shot is “very important,” and said Americans should not wait for a modified variant-specific vaccine before heading to the pharmacy.