By CBSLA Staff

RIVERSIDE (CBSLA) – Health officials say a COVID-19 antibody testing study indicates the virus may have infected roughly 6 percent of Riverside County residents – which would mean the vast majority of residents have not been infected.

The study was conducted over two weekends in July among randomly selected residents to determine whether they had been exposed to coronavirus and developed COVID-19 antibodies.

As part of the body’s defense against infections, antibodies develop and stay in the blood even after the infection is over.

Preliminary results showed out of 1,726 participants in the study who were tested for coronavirus, 101 showed they developed antibodies for COVID-19.

That marks a positivity rate of 5.9 percent, just slightly below statewide 14-day averages of roughly 7 percent.

Another 1,621 tested negative, while 4 had unclear results.

A health worker process the COVID-19 antibody test after getting the blood from the patient at the the Diagnostic and Wellness Center on May 5, 2020, in Torrance, California.  (Photo by VALERIE MACON / AFP) (Photo by VALERIE MACON/AFP via Getty Images)

Officials say based on that data, there have been somewhere between 118,000 and 175,400 infections in Riverside County, which has approximately 2.4 million residents.

The study was unique, according to county officials, in that it included both children 5 years and older and adults.

Residents were not permitted to volunteer for the study, in part, because health officials say they wanted a more representative sampling of the community.

“We believe the number and variety of participants shows the study successfully recruited an excellent representation of the community and accurately reflects the prevalence of the antibody in Riverside County,” said Dr. Tait Stevens, with Riverside University Health System and co-author of the study.

Like the coronavirus, however, antibody testing for COVID-19 is still relatively new. Health officials acknowledged that they still don’t fully know the benefits of testing positive for coronavirus antibodies.

Researchers say they do not yet know whether someone can contract COVID-19 again after a positive antibody test.

A UCLA study published last week suggested antibodies from a mild case of COVID-19 appear to fall dramatically in the first three months after infection, and could disappear within about a year.


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