September 28, 2020 -- Researchers who studied 28,500 patients across the United States concluded that less than 10% of the nation’s population has coronavirus antibodies in their systems.
The Stanford University scientists examined kidney dialysis patients’ plasma at about 1,300 facilities run by the same company in 46 states during July, according to the study published in The Lancet.
They found antibodies in plasma of 8.2% to 9.4% of the patients, the study said. Since dialysis patients aren’t fully representative of the American population, the researchers calculated in other factors such as age, sex, and race to extrapolate that 9.3% of the nation’s adult population has antibodies, the study says.
Race, income, and population density were also factors in infection rates.
People in predominantly Black and Hispanic neighborhoods had infection rates of 11.3-16.2%, compared to 4.8% for non-Hispanic White neighborhoods. Low-income areas had a two-times higher likelihood of infection and densely populated areas had a 10-times higher likelihood.
A news release from The Lancet announcing the study offered a recommendation that public health efforts should be concentrated in these populations to prevent community spread.
Researchers found “significant regional variation” in sampling results. Seven states, mostly in the West, had a 0% infection rate while a 25% rate was found in the Northeast. New York state had a 33.6% infection rate.
The Stanford findings line up with research from Johns Hopkins University and the CDC showing that most Americans are still vulnerable to the virus that has killed more than 200,000 people in the United States and 980,000 people worldwide. Just this week, CDC Director Robert Redfield, MD, told a Senate committee that 90% of the U.S. population is not yet immune to COVID-19.
"This research clearly confirms that despite high rates of COVID-19 in the United States, the number of people with antibodies is still low and we haven't come close to achieving herd immunity,” study author and Stanford professor Dr. Julie Parsonnet said in a statement. “Until an effective vaccine is approved, we need to make sure our more vulnerable populations are reached with prevention measures.”
Nine months into the COVID-19 pandemic, many questions about antibodies remain. Scientists are not absolutely certain antibodies provide immunity from catching the virus again. Nor are they certain how long antibodies stay in an infected person’s system.
The lead author of the study said dialysis patients were a good study group because they’re ethnically and socio-economically representative of the population.
“We were able to determine – with a high level of precision – differences in seroprevalence among patient groups within and across regions of the United States, providing a very rich picture of the first wave of the COVID-19 outbreak that can hopefully help inform strategies to curb the epidemic moving forward by targeting vulnerable populations,” Shuchi Anand, MD, director of the Center for Tubulointerstitial Kidney Disease at Stanford University, said in the release.