The SARS-CoV-2 virus may have been circulating in the United States as early as mid-December 2019, according to an analysis of Red Cross blood donations from that time period.

Researchers analyzed blood donations collected by the American Red Cross from residents in nine states between Dec 13 and Jan 17 and found evidence of antibodies in 106 out of 7,389 samples.

Antibodies also were found in 67 blood donations in January from states that didn’t report a widespread outbreak at the time, such as Connecticut, Iowa, Massachusetts, Michigan, Rhode Island and Wisconsin.