For only the seventh time since the first case of coronavirus was detected in Sonoma County six months ago, a person under the age of 65 has been killed by complications from COVID-19, county officials said Friday.

The death was among four reported late Thursday night, bringing the local death toll from the virus to 93. The county released additional information about the four patients on Friday, providing more insights into the way the virus is attacking the county’s most vulnerable residents.

One of the patients, a man between the ages of 45 and 64, died Aug. 31 after he was brought home from the hospital. The man had other health conditions and had been hospitalized for “an extended period of time,” according to county spokesman Paul Gullixson.

The three other deaths reported late Thursday occurred among people 65 or older and were residents of elder care or skilled nursing facilities. This age group, many of them infected in senior care facilities, account for 86 of the county’s 93 deaths.

“The majority of our deaths are still among our vulnerable seniors who are in skilled nursing facilities and residential care facilities for the elderly,” Sonoma County Health Officer Dr. Sundrai Mase said.

When asked if outbreaks at care homes continued to worsen, Mase said “I don’t think it’s a ’worse-or-better’ kind of a thing.“

“As each individual facility gets a case of COVID among an employee, that spreads and then the facility has to contain the outbreak,“ Mase said. ”Many of the skilled nursing facilities that had outbreaks two months ago are over them.“

State data shows that 330 residents at Sonoma County skilled nursing facilities have so far contracted the disease, in addition to 193 facility employees.

State infection control experts have visited local care homes to provide hands-on advice on how to stop outbreaks, Mase said.

Overall, the county has tracked 6,142 cases of COVID-19 — including 488 new cases this week alone — since the disease was first detected March 2. Of those, 2,360 cases are active while 60% have recovered.

Mase said recent data suggests the spread of the disease, though still prevalent throughout the community, has begun to ease.

The county still remains an outlier in the Bay Area for its infection rate — at 15.6 new cases per 100,000 population each day — which Mase said could indicate the high number of tests conducted daily in Sonoma County.

But there remain areas of concern, primarily social gatherings and workplace outbreaks.

She pointed to a recent spike of infections in Cloverdale due to cases among Latino residents, including cases detected among farmworkers who live in the community.

Mase drew distinctions between Sonoma County and neighboring Napa and Marin counties, pointing out that more essential workers both live and work here whereas many essential workers work in those areas but live elsewhere.

Teams of public health nurses are in communities conducting surveillance testing of vulnerable populations in skilled nursing facilities, among the homeless, at work sites for essential employees and other areas of concern, Mase said.

“We have high rates of positivity, which is a really good thing, it means that they’re testing the right populations, they’re singling out the most high risk,” Mase said.

You can reach Staff Writer Julie Johnson at 707-521-5220 or julie.johnson@pressdemocrat.com. On Twitter @jjpressdem.