Virginia health officials are urging caution and for people to protect themselves as omicron, a new variant of the coronavirus, rapidly spreads throughout the United States.

Omicron was first reported in South Africa but later discovered to have emerged earlier in Europe. It already has been found in more than 20 states, including Virginia, which reported its first case Dec. 10 in Northern Virginia.

State health officials are monitoring new cases and said the emergence was an inevitable part of dealing with COVID-19.

“We knew it was only a matter of time before we would record our first omicron infection in the Commonwealth,” Dr. M. Norman Oliver, the state health commissioner, said in a statement issued last week. “This drives home the challenge the COVID-19 virus presents to the world as the virus changes and mutates over time.”

Initial research has shown that omicron carries symptoms similar to those of other variants of COVID-19, including fever, cough, shortness of breath and muscle aches. A unique difference is that, for some infected with the omicron variant, there is no loss of taste or smell.

Health experts have said symptoms from omicron appear to be fairly mild so far. While those infected may face a less severe health impact, the mildness of symptoms may lead to people spreading it unintentionally, bolstering its transmissibility.

Health officials stressed the importance of following current COVID-19 guidelines and safety protocols, including getting the coronavirus vaccine and booster shots when eligible, wearing masks and social distancing around others.

“It’s really important to emphasize that those tools that we have to prevent transmission are still the best tools that we can use to fight against this variant and any other variants that come down the pipeline,” said Dr. Melissa Viray, deputy director of the Richmond and Henrico health districts. “If you haven’t gotten your vaccine yet, or you haven’t gotten your booster yet, now is a great time to do it.”

While children ages 5 and older can receive the COVID-19 vaccine, the U.S. Food and Drug Administration and federal Centers for Disease Control and Prevention have expanded eligibility for Pfizer booster shots to teens ages 16 and 17. Area health districts already have started offering the boosters to that age group.

The Richmond and Henrico health districts announced that their vaccination hubs will be closed for the holidays from Friday, Dec. 24, through Sunday, Jan. 2. The community vaccination center at Arthur Ashe Jr. Athletic Center on Arthur Ashe Boulevard will be closed, as well, from Thursday, Dec. 23, through Monday, Dec. 27. The Ashe Center site will reopen for vaccinations from 10 a.m. to 7:30 p.m. on Tuesday and Wednesday, Dec. 28 and 29, and from 8 a.m. to 4 p.m. on Thursday, Dec. 30. It will close for the New Year’s holiday on Friday, Dec. 31, and reopen from 8 a.m. to 6 p.m. Monday, Jan. 3.

For details on the walk-up vaccination centers or to schedule an appointment, go to vax.rchd.com or call (804) 205-3501.