The coronavirus was in the U.S. as early as mid-December 2019, a period earlier than officially identified in either China or the U.S., according to new research from the Centers for Disease Control and Prevention (CDC).
The study, published Monday, found evidence of the virus in 106 of 7,389 blood donations to the Red Cross in nine states.
These donations were collected between Dec. 13, 2019, and Jan. 17, 2020, with the Red Cross later submitting them to the CDC to test for antibodies.
Antibodies were detected in 39 samples on the West Coast in Washington, Oregon and California, all of them collected between Dec. 13 and 16. Antibodies were detected in another 67 samples in Connecticut, Iowa, Massachusetts, Michigan, Rhode Island and Wisconsin. Those samples were collected between Dec. 30 and Jan. 17.
Researchers said the antibodies were specific to COVID-19 and that they had ruled out other coronaviruses. COVID-19-specific antibodies were detected in 84 of 90 samples tested.
“The findings of this report suggest that SARS-CoV-2 infections may have been present in the U.S. in December 2019, earlier than previously recognized,” the researchers wrote.