Los Angeles County confirmed another case of the omicron coronavirus variant, and this infection could possibly be the result of local transmission, officials said Wednesday.

The latest omicron patient, who had mild symptoms, was fully vaccinated and had received a booster, according to the L.A. County Department of Public Health.

The person came in close contact with multiple people who have since tested positive for the coronavirus and are self-isolating. Health officials are working to determine whether they also have the omicron variant.

Several of the close contacts were fully vaccinated, officials said.

It’s the fifth omicron case in L.A. County, when counting one infection in Long Beach, which has its own public health department.

“The identification of a case of Omicron attributed to community spread is a reminder that we all need to take necessary precautions to prevent transmission of COVID-19,” L.A. County Health Director Barbara Ferrer said. “Celebrating with those we love this holiday season requires layering on the protections that are now available to us: vaccinations, boosters, masking up, and testing. This is how we slow the spread of Delta and Omicron.”

The latest confirmed omicron case is the first known one in L.A. County involving an infection attributed to community spread.

L.A. County’s first detected case of the omicron variant was reported on Dec. 2 and involved someone who had returned to L.A. County after travel to South Africa via London. Officials said that infection was “most likely travel-related.” 

The next confirmed omicron case in the county involved a USC student who had returned to the region after traveling for a holiday on the East Coast. The student likely became infected outside of L.A. County, based on travel history, officials said.

The third case of the new variant in the county involved someone who had recently traveled in West Africa.

Long Beach reported the county’s fourth omicron case. That person was asymptomatic and had traveled internationally.

So far, all five known omicron patients in the county were fully vaccinated and all of them experienced mild or no symptoms.

Nationwide, more than 40 people have been found to be infected with the omicron variant, and more than three-quarters of them had been vaccinated, according to the Centers for Disease Control and Prevention.

CDC chief Dr. Rochelle Walensky said nearly all of them were only mildly ill.

But that finding may be a result of the U.S. omicron patients being mainly vaccinated people, who are expected to have milder illnesses, health officials said. The CDC is still trying to determine whether omicron causes milder or more severe illness than other variants.

The omicron variant was first identified by scientists in South Africa last month and dubbed a variant of concern. Since then, it was reported in dozens of countries.

The first U.S. case was reported on Dec. 1 in San Francisco.

While scientists have yet to determine whether the new variant is resistant to vaccines, companies are already working to update their COVID-19 shots, just in case.

In the meantime, L.A. County Public Health told residents that getting vaccinated or boosted remains critical as holiday traveling and gatherings begin.

All residents were also told to mask up indoors and at large events, as well as get tested, especially if they traveled for the holidays, or had a possible exposure or developed symptoms.

A rapid COVID-19 testing site opened at the international terminal of LAX after the first case was reported locally.