More Than 400K L.A. County Residents May Have Been Infected With COVID-19, Per Antibody Study

Hollywood Boulevard - aerial view-COVID-19.- April 18, 2020- Getty-H 2020
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The number of daily deaths has decreased sharply in the county as the number of newly diagnosed cases has surged due to delayed testing results.

Anywhere between 221,000 and 442,000 Los Angeles County residents could have been infected with the COVID-19 illness, per a newly released antibody study done in partnership between USC and the L.A. County Department of Public Health.

The numbers represent preliminary results from the first round of testing done in early April at a time when there were only 7,994 confirmed cases of the novel coronavirus, showing that actual infections could have been 28 to 55 times higher, reflecting an estimated 4.1 percent of the county's population, which totals around 10 million. The data further confirms how easily transmittable the virus can be, while also significantly dropping the county's mortality rate, which last week had risen to 4.2 percent. 

Officials announced the study's results during Monday's coronavirus press briefing from L.A. County's Board of Supervisors headquarters in downtown Los Angeles, where L.A. County Public Health Director Dr. Barbara Ferrer was joined by chair Kathryn Barger, Public Health's chief science officer and co-lead on the study Dr. Paul Simon and lead study investigator Neeraj Sood of USC. 

Sood, a USC professor of public policy at the USC Price School for Public Policy and senior fellow at USC Schaeffer Center for Health Policy and Economics, said the estimates suggest that disease prediction models need to be recalibrated, as do public health strategies. The county has been under strict social distancing and safer-at-home guidelines since mid-March, a lockdown that currently remains in effect through May 15. The shutdown has decimated the economy, while COVID-19 has thus far claimed 617 lives across the county. 

"We are very early in [the] epidemic," Sood said. "Many more could be infected and as the number of deaths [increase], so will the number of hospitalizations and ICU admissions. We need to take the data we are getting to recalibrate the modeling and then ultimately use this better modeling to guide public policy decisions on how to combat this epidemic."

Public health officials across the country will be investigating the data as it relates to mortality. While the mortality rate in L.A. County reached 4.2 percent last week, the study suggests somewhere between .1 or .2 percent, low stats that do "provide some hope that this disease — while extraordinarily devastating and causing death in a much shorter period of time — is not as high a rate of death as what we were looking at," Ferrer said.

Study participants were recruited through a database maintained by market research firm LRW Group. The researchers used a rapid antibody test, administered with help from medical students from USC's Keck School of Medicine, USC researchers and Public Health officials at six drive-through sites on April 10-11. Researchers plan to test new groups of participants every few weeks in the coming months to gauge the pandemic's trajectory. The study was supported with funding from USC Schwarzenegger Institute, USC Lusk Center, USC President's Office, Jedel Foundation, LRW Group, Soap Box Sample and individual donors.

Also at Monday's briefing, Ferrer announced 1,491 newly diagnosed cases, but she was quick to point out that the high number is attributed to a backlog of test results and does not represent a single-day spike. Without the backlog of results, there would have been 293 newly diagnosed cases announced Monday. Currently, L.A. County has 13,816 confirmed cases. Of the 617 fatalities top date, 17 of those are from the previous 24 hours, a sharp decrease from the weekend, when 81 fatalities were reported Saturday, the highest daily total during the pandemic. So far, 89 percent of those who have died suffered from underlying health conditions, and right now there are 1,709 people hospitalized with the virus, while 30 percent of those are in an ICU.

Statewide, 1,208 California residents have died from COVID-19 illness. At his daily briefing Monday, Gov. Gavin Newsom said the curve continues to bend and flatten in the state, but the downward trend that “we need to see in order to provide more clarity for the roadmap to recovery” does not yet exist. He did, however, say that officials on Wednesday will roll out some details in the plan. At the time of Newsom's press conference, protesters gathered outside the state capitol to demand that he lift restrictive orders, allow businesses to reopen and thus restart the economy.

Asked about the protesters, the governor acknowledged the frustrations the pandemic has created for many of California’s 40 million residents, but he said “we must have a health-first focus if we’re ultimately going to come back economically.”

Newsom and Ferrer fielded questions about Ventura County's relaxation of stay-at-home orders. The area made a move to reopen golf courses, parks and other facilities, in the first major measure by a California county to ease life back to normal. Newsom and Ferrer both said they have been in contact with officials there, but Ferrer was quick to discourage local residents from flocking there as forecasts call for sunny 80-degree days later in the week. 

"Please don't go to Ventura to use their outdoor spaces," she cautioned. "You’ll overwhelm a county that is trying to relax their restrictions ... and you could inadvertently come back with an infection yourself and spread it here. We ask people to have more patience. As you can tell by the numbers we keep reporting, we have lots of people dying. We’re not at the point where we can, at this moment in time, relax our orders. I'm really asking people, please hang with us a little bit longer. Don't go up to Ventura County."