A woman traveling to New Jersey has become the state’s first known case of the omicron variant of the coronavirus, Gov. Phil Murphy’s office announced Friday evening.

Murphy and state Department of Health Commissioner Judy Persichilli said the woman is a fully vaccinated Georgia resident who had recently traveled to South Africa, where the variant was first identified to the world.

The woman tested positive Nov. 28 and has remained in isolation. Officials did not release her location.

However, they said she “experienced moderate symptoms and is now recovering after receiving care in a North Jersey emergency department.”

The Department of Health’s lab performed sequencing on the specimen and confirmed it as omicron.

The Georgia Department of Public Health confirmed the woman was in Georgia for two days between arriving from South Africa and traveling onward to New Jersey. She is also that state’s first known case.

The news comes on the heels of Philadelphia’s first known case, a man who tested positive for the variant, adding Pennsylvania to the growing list of states to detect the emerging variant. The city’s health commissioner is recommending that residents limit indoor socializing and reconsider having indoor holiday gatherings.

» READ MORE: First omicron case in Philadelphia detected, but ‘it is not unexpected,’ city says

“The omicron variant is among us and we need to take steps to stop its spread,” Murphy said. “It is vital that residents remain as vigilant as possible as we await more information about the variant. Vaccinations and mask wearing have proven to be an effective tool to reduce the spread of COVID-19, and I urge everyone ages 18 and over to receive a booster.”

Persichilli said that with coronavirus cases increasing and now with omicron in the state, “the fight against COVID-19 is not over.” She reiterated Murphy’s call for vaccines with booster shots, and masking, but she also called for people to physically distance, avoid crowds, stay home when sick, and wash their hands frequently.

Officials in New Jersey say they are working with other states, local health departments, laboratories, hospitals, and the CDC to identify individuals who may have been infected.

They say 70% of residents have received their primary vaccine series, but only 31% have received the recommended booster.

The World Health Organization identified the new variant as B.1.1.529 on Nov. 26. It called it a variant of concern and named it omicron.

Cases of omicron have also been detected as of Friday in New York, Nebraska, California, Colorado, and Hawaii. While much is still unknown about the variant, including how contagious it is or whether it can thwart vaccines, early reports are raising alarms. New COVID-19 cases in South Africa, which first alerted the world to omicron last week, have burgeoned from about 200 a day in mid-November to more than 16,000 on Friday.

Some of the U.S. cases involve people who hadn’t traveled recently, meaning the variant was likely already circulating domestically in some parts of the country.

The Associated Press contributed to this article.