A new study of blood specimens collected from 24,000 Americans found evidence that COVID-19 likely was present in the United States as early as Christmas Eve 2019.
The new retrospective research, published online Tuesday by the journal Clinical Infectious Diseases, found that nine people spread across Illinois, Massachusetts, Wisconsin, Pennsylvania and Mississippi had detectable COVID-19 antibodies in their bloodstreams when they participated in the government’s All of Us Research Program early last year.
The positive specimen collected from one Illinois-based patient on Jan. 7, 2020, suggests “the virus may have been present in Illinois as early as December 24, 2019,” a full month before Illinois confirmed its first official case of COVID-19 on Jan. 24, 2019, the study found.
The other blood that tested positive for the antibodies was collected Jan. 8, 2020, from Massachusetts; Feb. 3, 2020, from Wisconsin; Feb. 15, 2020, from Pennsylvania; and March 6, 2020, from Mississippi—weeks prior to the first recognized cases in those states, the researchers found.
The new findings corroborate a recent study of archived American Red Cross blood donation samples that found SARS-CoV-2–reactive antibodies in blood donations from California, Oregon and Washington as early as Dec. 13, 2019.