Five patients with laboratory confirmed COVID-19 diagnosis were chosen with the additional criteria of having severe pneumonia with rapid progression, specific oxygen levels and at the time of study were on ventilation or had been supported with ventilation. Blood types were determined for compatibility, and each patient received two consecutive transfusions of 200 to 250 ml of ABO-compatible convalescent plasma, for a total of 400 ml. Donors of the convalescent plasma had been previously diagnosed and subsequently tested negative. They had been asymptomatic for at least 10 days prior to giving plasma, and had a neutralizing antibody titer greater than 40. Nasopharyngeal specimens were taken from patients and used in RT-PCR assays, providing a Ct value. If Ct results were between 37 and 40, the specimen was considered positive. The Ct values of the 5 patients were obtained on day -1, 1, 3, 7 and 12 after the transfusion. Serum Neutralization