Scientists Report Earliest Known Coronavirus Infections in Five U.S. States

Blood drawn from nine people in the earliest days of the pandemic tested positive for the infection. But some experts questioned the results.

When did the coronavirus arrive in the United States? The first infection was confirmed on Jan. 21, 2020, in a resident of Washington State who had recently returned from Wuhan, China. Soon after, experts concluded that the virus had been in the country for weeks. A study published on Tuesday offers new evidence: Based on an analysis of blood tests, scientists identified seven people in five states who may have been infected well before the first confirmed cases in those states. The results suggest that the virus may have been circulating in Illinois, for example, as early as Dec. 24, 2019, although the first case in that state was confirmed a month later.