The U.S. Food and Drug Administration issued an emergency use authorization (EUA) for investigational convalescent plasma for the treatment of COVID-19 in hospitalized patients. The tests on 70,000 people suggest that the blood transfusion can reduced COVID-19 mortality by 35%.

This procedure is transferring antibodies in the blood of people who were infected with COVID-19 and then recovered. The antibodies are given to people who are hospitalized with COVID-19.

Convalescent blood plasma therapy has been used since the 1880s and was used against the Spanish Flu.