For Immediate Release:
April 20, 2020

For more information contact:
County of Los Angeles Public Health Communications
(213) 240-8144
media AT ph.lacounty.gov

USC-LA County Study: Early Results of Antibody Testing Suggest Number of COVID-19 Infections Far Exceeds Number of Confirmed Cases in Los Angeles County

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Los Angeles (April 20, 2020) - USC and the Los Angeles County Department of Public Health (Public Health) today released preliminary results from a collaborative scientific study that suggests infections from the new coronavirus are far more widespread - and the fatality rate much lower - in L.A. County than previously thought.

The results are from the first round of an ongoing study by USC researchers and Public Health officials. They will be conducting antibody testing over time on a series of representative samples of adults to determine the scope and spread of the pandemic across the county.

Based on results of the first round of testing, the research team estimates that approximately 4.1% of the county's adult population has antibody to the virus. Adjusting this estimate for statistical margin of error implies about 2.8% to 5.6% of the county's adult population has antibody to the virus- which translates to approximately 221,000 to 442,000 adults in the county who have had the infection. That estimate is 28 to 55 times higher than the 7,994 confirmed cases of COVID-19 reported to the county by the time of the study in early April. The number of COVID-related deaths in the county has now surpassed 600.

"We haven't known the true extent of COVID-19 infections in our community because we have only tested people with symptoms, and the availability of tests has been limited," said lead investigator Neeraj Sood, a USC professor of public policy at USC Price School for Public Policy and senior fellow at USC Schaeffer Center for Health Policy and Economics. "The estimates also suggest that we might have to recalibrate disease prediction models and rethink public health strategies."

The results have important implications for public health efforts to control the local epidemic.