Sonoma County awaiting tests for coronavirus antibodies

Sonoma County’s health officer is looking to first responders as part of an impending testing strategy to gain more insight on the true local spread of the coronavirus pandemic.

The plan to determine how many people might have coronavirus antibodies - a clear sign of prior infection - is on hold until Sonoma County receives the necessary examination materials, which are called serology tests, Dr. Sundari Mase said Friday in a conference call with reporters.

“The test itself has been ordered,” Mase said. “As soon as we get that serology test, yes, I’m going to come up with a plan for testing a representative sample of our county to see how many people may have been infected that we didn’t know of.”

A study of 3,300 people in Santa Clara County conducted this month by Stanford University researchers estimated that between 2.5% and 4.2% of residents there had antibodies to the coronavirus in their blood. That finding would put the total number of people infected with the virus between 48,000 and 81,000 - well higher than the officially reported figure of about 1,000 at the time of the study in early April, and a welcome indication that COVID-19’s mortality rate is lower than feared.

The exams used in the study to detect coronavirus antibodies are different than the tests used to determine whether a person is actively infected with COVID-19. It’s not yet clear how much immune protection comes with antibodies that linger in the blood of patients after they’ve recovered from the coronavirus, as some people have tested positive a second time for the virus after appearing to recover.

Health officials in Southern California have said they plan to make their initial results public Monday.

Noting that local first responders have experienced COVID-19 cases, Mase said they would likely be prioritized in initial antibody testing.

“There’s definite plans for using that antibody test, but we have to get it first,” she said.

A county spokesman, Rohish Lal, could not respond Saturday to a question about how many serology tests the county planned to perform, when it expected to receive these tests or when and how the testing would be done; he noted that the tests “are on back order due to high demand.”

Sonoma County reported no change in the number of coronavirus cases on Saturday. To date, the county has had 180 cases of COVID-19, with 91 of those considered active. Two people have died, and the remaining 87 people have recovered. The county has tested 4,389 people for coronavirus, with 4% of tests coming back positive.

State health officials released a list of 261 skilled nursing facilities statewide where a resident or health care worker had reported a COVID-19 case as of Friday, with 86% of more than 1,200 facilities statewide reporting data.

The only entry on the list in Sonoma County is at the Apple Valley Post-Acute Rehab in Sebastopol, where an asymptomatic staff member tested positive as part of the county’s surveillance testing program. The state did not say exactly how many cases were present in the Sebastopol facility or others that had low totals, noting only that Apple Valley and the others had fewer than 11 cases.

Also, surveillance testing Friday for COVID-19 of about 40 people at the Sonoma County Jail returned no positive cases, Lal said on Saturday.

You can reach Staff Writer Will Schmitt at 707-521-5207 or will.schmitt@pressdemocrat.com.

On Twitter @wsreports.