31% Of Americans Caught COVID In 2020: Columbia University
Almost one-third of Americans could have been infected by the coronavirus in 2020, according to Columbia University estimates, Deutsche Presse-Agentur (dpa) reported.
Photo Insert: 103 million people caught the virus last year.
Published in Nature, the research by the Ivy League university's Mailman School of Public Health suggests 103 million people, or 31 percent of the population, caught the virus last year.
"The vast majority of infectious were not accounted for by the number of confirmed cases," said Jeffrey Shaman, professor of environmental health sciences at Columbia.
Official numbers accounted for only 10 percent of total estimated infections at the outset of the pandemic in March, when testing was not widely accessible, but rose to 25 percent by December, according to the researchers.
"Individuals with mild or asymptomatic infections, who could still spread the virus, were less likely to be tested," they said. Testing and treatments improved over time, meaning "the percentage of people with infections who died from COVID-19 fell from 0.8 percent during the spring wave to 0.3 percent by year's end," when 25 percent of real infection numbers were reflected in official counts.
An undercount of infections would mean the virus is less deadly than official numbers suggest, widening the infection-fatality rate substantially beyond the official case-fatality rate.
The cumulative case-fatality rate for the US was 1.6 percent on August 25, according to official numbers collated by the University of Oxford's Our World in Data. The National Academy of Sciences last month published estimates by the University of Washington suggesting around one-fifth of Americans had caught the virus by March this year.