LOS ANGELES (CNS) — The BA.2 subvariant of COVID-19 is continuing to strengthen its presence in Los Angeles County, now accounting for nearly one-third of all virus cases that are screened for variants, the public health director said Thursday.

The spread of the highly infectious variant, however, has not translated into a rise in virus-related hospitalizations, likely attributable to relatively high numbers of people who are vaccinated.

For the week that ended March 12, 32% of COVID infections that underwent laboratory sequencing turned out to be the result of BA.2, which is an offshoot of the omicron variant that fueled a surge in cases over the winter months. Omicron is still the dominate variant found in the testing, but the percentage of BA.2 cases has been steadily increasing.

During the week ending March 5, 16.7% of sequenced cases were found to be BA.2. The percentage was only 6.3% the previous week.

County Public Health Director Barbara Ferrer on Thursday noted that since the testing reflects cases from two weeks ago, BA.2 most likely now accounts for an even higher percentage of COVID infections.

But she said that as of Sunday, only about 3% of visits to hospital emergency departments in the county are COVID-related.

"Despite the BA.2 increases that we're starting to see, they're not resulting yet in increases in COVID-19 emergency department visits," she said.

The county is beginning to see a leveling off of the declines in COVID case numbers that have marked the past several weeks, with the county now averaging about 660 cases per day.

"The rate of decline has been slower, and this week we're not seeing any declines in the cases," Ferrer said.

She said it's too early to call that leveling-off a "concern," but she termed it "notable."

"At some point we knew that it was likely we were going to stop declining," she said. "We know there's still transmission. ... Personally, I wish we were at a lower level when we're doing this plateauing, but we have seen a significant decrease, and that's the good news."

She noted that the slowing of the decline could be related to the recent lifting of COVID health measures, such as indoor masking requirements. The county on Friday, along with the state, will lift the vaccine or negative-test verification requirement at indoor mega-events, such as sporting events and concerts.

"Every single time we have reduced the restrictions or levels of protection that are required, we have always seen an uptick (in cases)," Ferrer said. "The slowing of the decline can also be seen in some ways as an uptick."

The county on Thursday reported 784 new COVID cases, along with 16 additional virus-related deaths. The numbers raised the county's cumulative totals to 2,833,206 cases and 31,669 deaths.

The average daily rate of people testing positive for the virus was 1.1% as of Thursday, up slightly from the roughly 0.7% rate from the past few weeks. The rate was 0.9% on Wednesday. 

The number of COVID-positive patients in county hospitals fell to 308 on Thursday, down from 325 on Wednesday. The number of those patients being treated in intensive care was 47, down from 51 a day earlier.

Los Angeles County this week began offering second booster doses of COVID-19 vaccine, following approval of the additional Pfizer and Moderna shots by the U.S. Food and Drug Administration. The additional boosters were authorized for people who are age 50 and over, and who received their last booster shot at least four months ago.

Boosters are also available for younger people who are considered immunocompromised and at higher risk of severe illness from the virus.

Information about vaccination sites is available online at VaccinateLACounty.com.

According to the county, as of Sunday, 83% of eligible county residents age 5 and older had received at least one dose of COVID vaccine, and 75% were fully vaccinated. However, only 31% of children aged 5-11 have been fully vaccinated, the lowest rate of any age group.