Researchers are launching a study to see whether blood plasma from coronavirus survivors can block infection in others. The study will involve people in groups at high risk of getting infected. This could include health workers, husbands or wives of sick individuals and people who live in nursing homes. The new research will build on recent studies that looked into whether blood plasma from recovered coronavirus patients could be an effective treatment for infected individuals. Plasma is the yellowish, liquid part of blood. It contains proteins called antibodies that target infections entering the body. Blood plasma from former patients may help infected individuals defeat COVID-19, the disease caused by the coronavirus. Many survivors of COVID-19 have donated their blood plasma in hopes of helping sick patients recover. Thousands of coronavirus patients in hospitals around the world have been treated with this kind of plasma, including more than 20,000 in the United States. So far, there is little evidence to demonstrate that blood plasma is helping coronavirus patients recover.