First Case of Omicron Variant Detected in the U.S.

First Case of Omicron Variant Detected in the U.S.
People check-in for their covid-19 vaccine at a pop-up clinic offering vaccines and booster shots in Rosemead, California on November 29, 2021 (Photo: Fredric J. Brown/AFP, Getty Images)

The Omicron variant of the coronavirus has officially reached the United States. This afternoon, the Centres for Disease Control and Prevention confirmed the first case of the worrying variant, involving a California resident who recently returned from South Africa, where the variant was first identified. The patient was fully vaccinated, is reportedly experiencing mild symptoms that are improving, and has self-isolated.

Late last week, researchers in South Africa reported the existence of the Omicron variant, a version of the SARS-CoV-2 virus with many mutations compared to currently dominant strains. The first cases of Omicron discovered in the country so far date back to early November, but it’s not clear at this point where the variant originated. Cases have since been found in 23 countries as of this morning, including Italy, Japan, and Brazil. And now the U.S. is the latest to join the list.

The U.S. case was first confirmed by the California and San Francisco Departments of Public Health, following genetic sequencing of the patient’s coronavirus sample by researchers at the University of California, San Francisco. The CDC then confirmed that this sequence was consistent with Omicron, the agency said in its statement about the case.

According to the CDC, the fully vaccinated patient had returned from a trip to South Africa on November 22. They’re still testing positive for the virus, indicating an ongoing infection, but are only experiencing mild illness and improving symptoms. Close contacts of the patient have been identified and tested, with none testing positive.

Scientists are concerned that Omicron may be more transmissible than past variants, due to the dozens of relevant mutations it carries compared to the original SARS-CoV-2 coronavirus first identified in late 2019. It’s possible that these mutations may allow it to better evade the immune system of those previously vaccinated and infected, and/or that it may be inherently better at transmitting itself from person to person. But there remains much unknown about the risks posed by Omicron, and it will likely take weeks at the earliest to understand its added potential for harm. Similarly, it is not known yet whether Omicron is any different in its ability and likelihood to cause illness compared to past strains.

Experts, including those at the CDC, remain optimistic that Omicron can be managed by the existing tools we’ve developed to contain the pandemic.

“The recent emergence of the Omicron variant (B.1.1.529) further emphasises the importance of vaccination, boosters, and general prevention strategies needed to protect against COVID-19,” the CDC said in its statement. “Everyone 5 and older should get vaccinated boosters are recommended for everyone 18 years and older.”


Editor’s Note: Release dates within this article are based in the U.S., but will be updated with local Australian dates as soon as we know more.