This case series showed convalescent plasma was well tolerated and has potential to improve the clinical outcomes of severe COVID-19 cases. The optimal dose and timing, as well as the true clinical benefit, needs further study in larger well-controlled trials.

Researchers enrolled 10 severely infected patients with COVID-19. Each was given one dose of 200 mL of convalescent plasma derived from recently recovered donors with neutralizing antibody titers above 1:640. They were also given supportive care and antiviral agents.

The median time from illness onset to convalescent plasma transfusion was 16-17 days. After convalescent plasma transfusion, the level of neutralizing antibody increased rapidly up to 1:640 in five cases, and four others maintained a high level (1:640). The clinical symptoms were significantly improved, as was oxyhemoglobin saturation in 3 days. Other parameters that improved included lymphocyte counts and C-reactive protein.

Radiological examinations showed varying levels of improvement. The viral load was undetectable after transfusion in seven patients who detectable levels beforehand. No severe adverse effects were observed.