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100K+ in Riverside County could have coronavirus unknowingly, new antibody study says

A new antibody testing study shows the spread of coronavirus could be more expansive than is being reported – maybe by as much as 5 times what current testing is showing.

The Riverside University Health System announced that the results of the COVID-19 antibody testing study have led to estimations that up to 175,000 Riverside County residents could be infected with coronavirus.

The randomized study was conducted over two weekends this month. Officials said results are still being analyzed.

As part of the study, health officials hoped to test 3,500 randomly selected residents, but only 1,726 individuals were tested. The tests are being used to determine whether they had been exposed to coronavirus and developed COVID-19 antibodies.

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

County health officials released some preliminary results from the study:

  • 1,726 individuals were tested and 101 showed they had developed antibodies for COVID-19, this is a positivity rate of 5.9 percent.
  • 1,621 tested negative; Four had unclear results.

Officials say that based on this data, it's estimated there have been between 118,000 and 175,400 infections in Riverside County. That's 3 to 5 times the actual number of positive tests: 35,187 as of Monday.

"This study describes the prevalence of COVID-19, which will be used to inform planning efforts. This study is unique in that it included both children (5 years and older) and adults," reads a news release from Riverside County officials.

RUHS will not be creating a list of participants and will not collect the individual information from the study.

"The data gleaned from the study provides important information that will help guide our efforts and direction as we move forward," said Dr. Errin Rider, laboratory director for Riverside University Health System-Public Health. "We appreciate those who agreed to take part in the study; they have contributed to the fight against the pandemic."

The study was random, residents weren't able to volunteer for the study because health officials 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.

Health officials want to remind people that the medical community still doesn't know the extent of the benefits of testing positive for coronavirus antibodies. For example, it is still not known if someone can get the virus again after testing positive for antibodies.

"We continue to learn new information about coronavirus, and this survey adds important research to the growing knowledge of COVID-19," said Riverside County Board Chair and Fourth District Supervisor V. Manuel Perez. "We still must protect everybody out there who is susceptible to getting sick, and we should do so by wearing face coverings, physical distancing, washing our hands and avoiding gatherings."

Officials say the study continues to show why residents need to wear face coverings as people may have the virus without any symptoms then easily spread it to others when not wearing a mask or keeping six feet of distance.

On Friday, the County announced an initiative to giveaway 10 million masks to residents.

“We fight the virus with medicine, and in the absence of a vaccine, these masks are medicine,” said  Lou Monville, Chair of the Riverside County Economic Recovery Task Force.

Stay up-to-date with the latest local coronavirus news, including reopenings and closing, new case data, live news conferences, and other updates at or download the News Channel 3 app on the Apple Store and Google Play.

Article Topic Follows: Coronavirus

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Jesus Reyes


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