The first case of the omicron COVID-19 variant in the United States was recorded in California on Wednesday.

The California and San Francisco Departments of Public Health confirmed the case was caused by the omicron variant, according to a Centers for Disease Control and Prevention press release.

The individual infected had returned from South Africa on Nov. 22 and was fully vaccinated. They are currently in self-quarantine, added the release.

According to a tweet from California Gov. Gavin Newsom, the discovery of the variant in California likely indicates it is already in other states as well.

“There’s no reason to panic–but we should remain vigilant,” Newsom said in the tweet. “That means get vaccinated. Get boosted. Wear a mask indoors.”