LOS ANGELES (CNS) — While local COVID-19 transmission remains "high" under federal standards, Los Angeles County has seen three consecutive weeks of decline in its weekly infection rate, an improvement the public health director Friday attributed in part to mask mandates and slowly rising vaccination numbers. 

Under benchmarks set by the U.S. Centers for Disease Control and Prevention, transmission is considered in the "high" category if there are cumulatively 100 or more new cases per 100,000 residents over the course of a week. Much of the country is currently in the "high" transmission category.

Los Angeles County's rate, however, fell this week to 104 cases per 100,000, a "welcome" 35% drop from last week, Public Health Director Barbara Ferrer said.

"This is the third week in a row we've seen decreases in our case rate," Ferrer said. "Overall, we've seen a nearly 50% decrease from our peak of 204 cases per 100,000 people on Aug. 19. It's worth noting that recent declines may reflect the masking requirements implemented early in the surge and the small increases in our vaccination coverage.

"Other parts of the country that don't have masking requirements and don't have as much vaccination coverage have not seen these significant declines in cases," she said.

If the county's rate continues to decrease and falls below 100 new cases per 100,000 residents over a seven-day period, it could move into the CDC's less-severe "substantial" transmission category.

But Ferrer warned that a reversal of fortune could still occur. 

"While we welcome the decreases, we do anticipate that with increased routine screening testing and intermingling at schools and worksites, along with Labor Day travel and gatherings, we do face the risk that our case numbers could once again increase," she said.

Ferrer also again lamented the slow pace of vaccinations in the county. She said over the past week only about 56,000 first doses were administered in the county.

"We are making very little progress," she said.

Ferrer expressed hope that vaccination mandates like those announced Thursday by the Los Angeles Unified School District for eligible students 12 and over and by President Joe Biden for workers at large companies will have an impact.

She also repeated the assertion that vaccinated people continue to represent a fraction of new COVID infections and hospitalizations. According to August figures, unvaccinated people in the county were 4.2 times more likely to get infected, 11.7 times more likely to be hospitalized and 10 times more likely to die from COVID-19.

Of the nearly 5.4 million fully vaccinated people in the county as of Sept. 7, 43,598 had tested positive, for a rate of 0.81%, she said. A total of 1,243 fully vaccinated people have been hospitalized, for a rate of 0.023% and 165 have died, for a rate of 0.0031%.

According to the most recent numbers, 75% of eligible county residents aged 12 and over have received at least one dose of vaccine, and 66% are fully vaccinated. Among the county's overall population of 10.3 million, 65% have received one dose and 57% are fully vaccinated. That population figure includes roughly 1.3 million people under age 12 who are ineligible for shots.

Black residents in the county continue to have the lowest vaccination rate, at 51% overall with at least one dose. Among Black residents aged 12-15, just 35% have received at least one dose.

The county reported 50 new COVID-19 deaths on Friday, raising the cumulative death toll during the pandemic to 25,611. Another 2,024 cases were also reported, giving the county an overall pandemic total of 1,427,817.

The average daily rate of people testing positive for the virus in the county was 2.6% as of Friday, down slightly from last Friday. 

According to state figures, there were 1,321 COVID-positive patients hospitalized in the county, down from 1,368 on Thursday. It's the 11th day in row the hospitalization number has fallen. There were 387 patients in intensive care, down from 404 on Thursday.

The county last week announced that it had identified 167 instances of the Mu variant of COVID-19 locally. But Ferrer said Friday that a lab reanalyzed samples dating back several months, and determined there have actually been 232 cases of the Mu variant locally, along with 28 instances of the Lambda variant.

While the Mu variant has raised eyebrows over concerns it could potentially evade vaccines, it has not yet risen to the level of being considered a "variant of concern" by health officials. Ferrer said the highly infectious delta variant is still the biggest threat, representing nearly 100% of all samples that undergo genetic sequencing to identify variants.

Los Angeles County will not be reporting daily COVID-19 case numbers over the weekend, with Ferrer saying the health department will be working on upgrades to its data processing systems.