LOS ANGELES (CNS) — With winter months and colder weather approaching, Los Angeles County’s health director urged residents Thursday to receive a COVID-19 vaccine booster shot to fend off what could be another jump in transmission of the virus as more people mingle indoors — a setting conducive to infection.

“I hope we can rally as a community and make every effort to protect our most vulnerable residents,” Barbara Ferrer told reporters during a briefing Thursday.

She noted that millions of county residents are currently eligible to receive the new COVID-19 booster shot, which is specifically engineered to target the most widely circulating viral variants. She said understands the “fatigue” people have over calls to get vaccinated, but the low number of residents who have received the new booster is a cause for concern.

“Those numbers need to increase pretty dramatically before we get into the holiday season or we run the risk of having more transmission,” Ferrer said.

Recent testing of COVID-19 samples has shown a small but discernable increase in a number of new variants of the virus, most notably a variant known as BA.4.6, which represented 5% of tested samples, up from 3% a week ago. The county has also now detected three samples of BA.2.75.2, which has been spreading in parts of Asia and Europe and appears to be able to avoid current vaccinations. Samples of a variant known as BF.7 have also been detected.

Health officials have long warned that as long as the COVID continues spreading, the more likely it is that mutations, or variants, will develop that could spread more quickly or cause more severe illness.

Ferrer said the county will be closely watching trends in variants locally, noting that while the increases thus far are small, they could potentially spread more as people spend more time indoors during the winter. With more people mingling inside, “a variant that has an advantage in transmission and evades protections more easily will flourish,” she said.

“We need to be prepared for increases that are likely going to be associated with colder weather,” Ferrer said.

According to state figures, there were 516 COVID-positive patients in county hospitals as of Thursday, up from 501 on Wednesday. Of those patients, 66 were being treated in intensive care, up from 65 a day earlier.

COVID hospitalizations numbers have been generally declining over the past few months, reflecting overall decreases in virus transmission in the county. In mid-July, there were more than 1,300 virus-positive patients in county hospitals.

County officials have said that roughly 40% of those patients were admitted specifically for COVID, while the others were hospitalized for other reasons but tested positive upon admission.

The county reported 12 more virus-related fatalities Thursday, raising the overall death toll to 33,730. Another 1,822 infections were also reported, giving the county a cumulative total from throughout the pandemic of 3,462,836.

Daily case numbers reported by the county have been steadily falling for weeks, although health officials have conceded that the official figures could be misleading due to residents primarily using at-home tests that aren’t reported to the county.

As of Thursday, the average seven-day rate of people testing positive for the virus in the county was 5%.