An analysis of donated blood suggests SARS-CoV-2 was present in the US weeks earlier than thought, NPR reports. It notes that some of these infections may have occurred before the outbreak in Wuhan, China.
Researchers from the US Centers for Disease Control and Prevention and the American Red Cross tested residual archived blood donation samples from 7,389 individuals who gave blood between mid-December 2019 and mid-January 2020 for antibodies against SARS-CoV-2. As they report in the journal Clinical Infectious Diseases, the researchers found 106 samples were reactive by pan-Ig ELISA testing and of the 90 samples available for further analysis, 84 had neutralizing activity.
The blood samples tested came from nine states and suggest SARS-CoV-2 was present in California, Oregon, and Washington State as early as mid-December 2019, NPR says.
The first confirmed case of COVID-19 in the US was not until mid-January 2020, and Bloomberg notes that other studies have suggested SARS-CoV-2 might have been present in regions outside of China before 2020.