Researchers estimate 14% of US population had SARS-CoV-2 by mid-November
Adjusting for under-reporting, researchers estimated that approximately 14% of Americans had been infected with SARS-CoV-2 by mid-November, suggesting the burden is much larger than the reported case count, they said.
“Reported COVID-19 cases underestimate the actual number of SARS-CoV-2 infected persons,” Frederick Angulo, DVM, PhD, a medical epidemiologist for Pfizer Vaccine, told Healio.
Angulo and colleagues conducted a cross-sectional study to estimate the total number of SARS-CoV-2 infections, hospitalizations, symptomatic infections and deaths in the U.S. They used data from four CDC seroprevalence surveys conducted in April, May, June and August — which included data from 95,768 individuals — to account for underreporting. The researchers then used community serosurvey data from randomly selected individuals in the general population to confirm the underreporting.
In total, they calculated that 46.9 million SARS-CoV-2 infections (interquartile range [IQR] = 38,192,705-60,814,748), 28.1 million symptomatic infections (IQR = 23,014,957-36,438,592), 956,174 hospitalizations (IQR = 782,509-1,238,912) and 304,915 deaths (IQR = 248,253-395,296) occurred in the United States through Nov. 15. As of Jan. 5, there were just under 30 million reported cases of COVID-19 in the U.S., according to tracking by Johns Hopkins University.
“Estimates of SARS-CoV-2 infections are needed to understand how interventions can be titrated to reopen society,” the researchers wrote.
They said further surveys are necessary to monitor COVID-19, as well as the distribution of effective vaccines.
“Even with the large, continued wave of COVID-19 infections in the U.S., the U.S. remains a long way from acquiring the level of herd immunity necessary for disrupting SARS-CoV-2 transmission,” Angulo said. “Continued seroprevalence studies are needed to monitor progress toward herd immunity.”