COVID-19 antibodies found in blood donated by Americans in December 2019

Editor's Note

COVID-19 virus antibodies were detected in 106 specimens from American Red Cross blood donations in California, Oregon, and Washington, as early as December 13-16, 2019, finds this study by researchers from the Centers for Disease Control and Prevention and American Red Cross.

Similarly, antibodies were identified in blood donated in early January in Connecticut, Iowa, Massachusetts, Michigan, Rhode Island, and Wisconsin, prior to known introduction of COVID-19 into those states.

Of 7,389 blood samples tested, 106 had SARS-CoV-2-reactive antibodies present, and 90 were available for further testing. Of these, 84 had neutralizing activity, 1 had S1 binding activity, and 1 had receptor-binding domain/ACE2 blocking activity >50%, suggesting the presence of anti-SARS-CoV-2-reactive antibodies.

The findings suggest that COVID-19 may have been introduced into the US before January 19, 2020, when the first infection was reported in a returned traveler from China, the researchers say.