Today researchers at the University of Miami released the preliminary results of serology (antibodies) testing in Miami-Dade County. They estimate that 6% of the population – or 165,000 residents – have been exposed to the disease. According to this write-up: “The researchers say they are 95% certain that the true amount of infection lies between 4.4% and 7.9% of the population, with 6% representing the best estimate.” The methodology for the sample appears to have been more robust than that applied in the Stanford group’s studies in California. Researchers say they used data from electrical utility Florida Power and Light to generate phone numbers in targeted demographic areas who were then contacted asked to voluntarily provide samples.
The study’s lead researcher is Erin Kobetz, a University of Miami professor of medicine and public health sciences.
Another notable number. The finding of 165,000 residents is roughly 15x higher than the Miami-Dade’s official number of lab confirmed cases. The study released by New York State yesterday pointed to roughly 12x the number of infections in New York City as the official lab confirmed number.
Given the various uncertainties involved – rates of error in the serology testing, difficulties finding truly random pools, different intensity of testing for the disease in different regions – these are fairly consistent multiples. Indeed, multiples of 10x to 12x are what many epidemiologists and public health experts working on the COVID19 response have predicted.
