Early results from antibody testing in Colorado suggest far more people have been infected with the novel coronavirus than recorded confirmed cases account for, thus drastically dropping the estimated fatality rate of COVID-19, analysis from Reason argued Wednesday.
United Biomedical, in collaboration with the Department of Health and Environment, is seeking to roll out some 8,000 antibody tests in coming days or weeks. Thus far, they have taken 6,000 blood tests, of which 986 have been processed.
According to a release from the San Miguel County Public Health Department, of the 986 processed tests from late March, 955 came back negative, eight were positive, and 23 were ambiguous or “borderline.”
The health department explained the three results as follows:
A positive result on the first blood test means that individual has been exposed to COVID-19 (and may or may not have ever experienced symptoms).
An indeterminate or borderline result on the first test indicates that the result produced a “high-signal flash” which is not enough to produce a positive result. It means that the individual may have been recently exposed to COVID-19 and/or may be in the early stage of producing antibodies.
A negative result on the first blood test means that an individual either has not been exposed to COVID-19 –OR— the person is in the window of having recently been exposed and has not yet developed antibodies that would make the test result be positive.
“Counting only the positive results, and assuming this initial sample is representative of the county, these findings suggest that something like 0.8 percent of the local population has been infected by the virus,” Reason explained.
However, due to San Miguel County’s population density, “the prevalence of infection is likely to be a lot higher in areas of the country where people are more closely packed together,” the outlet said, noting that the “average population density for the entire country is 94 people per square mile, 16 times the rate in San Miguel County.”
“Applying the low prevalence estimate for San Miguel County to the national population implies something like 2.6 million infections,” Reason noted. “Applying the high estimate raises that number to nearly 10 million, compared to 418,000 confirmed cases at last count. And whatever the actual prevalence is in San Miguel County, the national average is apt to be substantially higher.”
On the low end of infection prevalence, Reason estimates “the crude case fatality rate (CFR) for the United States, currently 3.4 percent, drops to something like 0.5 percent, which would make COVID-19 about five times as deadly as the seasonal flu.”
Looking at the high end of infection prevalence, “the actual fatality rate would be only slightly higher than 0.1 percent, the estimated CFR for the flu.”
Of course, there are caveats and unknowns. For example, is the fatality count for COVID-19 inflated, or is undercounted? As noted by Dr. Deborah Birx, the United States is recording coronavirus in “very liberal” fashion; if someone has COVID-19, “we are counting that,” the influential doctor said at a recent White House briefing. However, Dr. Birx also made note that deaths in January and February were likely undercounted, since the disease was not fully on our radar, nor were tests as readily available.
If the deaths are undercounted, it would wrongly skew the fatality rate too low; and if they are inflated, the death rate would be skewed too high.
“Even allowing for delayed and undocumented deaths, it obviously makes a huge difference whether the overall prevalence of infection in the United States is 0.1 percent, as the official tally improbably suggests; close to 1 percent, as the initial tests indicate for San Miguel County; or several times that figure, as we might surmise based on relative population densities,” Reason concludes.