One in three Americans had COVID-19 by the end of 2020, study estimates

A new study estimates that 103 million Americans, or 31 percent of the U.S. population, had been infected with SARS-CoV-2 by the end of 2020. Researchers modeled the spread of the coronavirus, finding that fewer than one-quarter of infections (22 percent) were accounted for in cases confirmed through public health reports based on testing.