- Dec 12, 2018
In early April, Stanford University researchers conducted an antibody test of 3,300 residents in the county that were recruited through targeted Facebook ads. Researchers hoped to put together a sample that was representative of the county's population by selecting individuals based on their age, race, gender and zip code to extrapolate study results to the larger community.
The results of the study are preliminary and not peer-reviewed, but the general takeaways would seem to strongly contribute to the notion that there have been a large number of COVID-19 cases that went undetected.
Researchers estimate that if 2.5 to 4.2 percent of the county has already been infected, the true number of total cases in early April — both active and recovered — ranges between 48,000 and 81,000. The county had reported just under 1,000 cases at the time the study was conducted, which would mean cases are being underreported by a factor of 50 to 85.
If the study's numbers are accurate, the true mortality and hospitalization rates of COVID-19 are both substantially lower than current estimates, and due to lag between infection and death, researchers project a true mortality rate between .12 and .20.
Results also suggest the county is nowhere near "herd immunity," as scientists estimate that 50-60% of the population would need to be infected for the virus to have nowhere to spread.
However, the study's authors caution against extrapolating Santa Clara County results to the rest of the country. The county reported its first case on January 31, and was one of the early national "hot spots" where the virus had gained a foothold. Researchers also acknowledge other limitations of the study, including an overrepresentation of white women between ages 19-64, and "other biases, such as bias favoring individuals in good health capable of attending our testing sites, or bias favoring those with prior COVID-like illnesses seeking antibody confirmation."
Large-scale Santa Clara antibody test suggests COVID-19 cases are underreported by factor of 50-85
It has long been assumed by medical experts that the United States is drastically...