Stanford researchers to study coronavirus in Placer County

Placer County joined a study this week with Stanford University to better understand the rates of COVID-19 infection among its residents.

“Led by Stanford University School of Medicine, study investigators will test blood samples from 2,000 residents for COVID-19 antibodies, which indicate a previous coronavirus infection,” the county said in a news release.

This week, Placer County recorded more that 3,800 positive tests for “SARS-CoV2, the coronavirus that causes COVID-19,” the county said.

But health officials suspect the true number of those infected may be higher because some people who contracted the virus were asymptomatic, and may not have been tested. According to experts in the Stanford School of Medicine, it is estimated that the infection rate in Placer County may actually be between 1.3 and 6% of the county’s population. The current infection rate is 2%, according to the county’s COVID-19 dashboard.

“Knowing how widespread COVID-19 really is in our community would tell us a lot about how close we are to achieving some form of immunity and the true fatality rate from the disease,” said District 2 Supervisor Robert Weygandt said in a prepared statement. “That’s critical information to guide decisions that best protect the physical, social and economic well-being of our communities.”

To gather data for the study, researchers will select a representative sample of residents and mail finger-stick blood tests to willing participants.

“The results of all positive tests and 10% of negative tests will be rerun using a different type of test, producing results with 99% accuracy,” according to the news release.

It’s expected the study will take about five months to complete.

Researchers will then create an online dashboard of their findings on the demographic and geographic prevalence of the virus within the county. The results will be presented to the Board of Supervisors.