Serological Testing in Los Angeles Confirms Santa Clara Study, But Not Without Controversy

The results of a random, serological study conducted in Los Angeles County broadly confirmed similar results of a serological study out of Santa Clara County last week, with both tests showing roughly the same thing: Thousands and thousands of more people have been infected than have been reported, but that it’s nowhere near the number necessary for herd immunity.

Based on a random sampling in Los Angeles county, antibody test shows that 2.8% to 5.6% of adults have antibodies to the virus in their blood — or 221,000 to 442,000 adults — compared to the 8,000 reported cases in the county. The Santa Clara study showed similar results, with 2.5% to 4.2% of adults tested adults appearing to have antibodies to the virus, or 48,000 to 81,000 people, compared to the 1,000 reported cases.

The results in both studies have not yet been peer-reviewed, and there is some question about the accuracy of the antibody tests. The same tests were used in both counties, and though they do not have FDA approval, they were approved by a hospital. Meanwhile, the results of the Santa Clara study came under fire yesterday for “sampling and statistical imperfections,” in part driven by the way it chose who to test. However, in Los Angeles, they used a market-research firm to find a random sampling.

More studies will need to be done, and this particular study in Los Angeles will be carried out every two to three weeks to see how the virus spreads over the long term. In the meantime, the results of both tests seem to suggest good news and bad news: If these results are accurate, the fatality rate is much lower than previously believed — a .1 to .2 fatality rate, which is in line with the seasonal flu — but that the disease is spread among asymptomatic and presymptomatic people far more than we previously believed. Results from both studies, in fact, make clear that at least 95 percent of those counties have not yet been exposed.

Meanwhile, Governor Cuomo is rolling out aggressive antibody testing in New York this week. He plans to conduct the “largest survey of any state population that has been done,” and the results should provide an even clearer picture of the spread of the disease, the infection rate, and the fatality rate.

Source: LA Times