Outpatient convalescent plasma therapy for high-risk patients with early COVID-19: a randomized placebo-controlled trial

Abstract

ObjectivesThe potential benefit of convalescent plasma (CP) therapy for coronavirus disease 2019 (COVID-19) is highest when administered early after symptom onset. Our objective was to determine the effectiveness of CP therapy in improving the disease course of COVID-19 among high-risk outpatients. MethodsA multicentre, double-blind randomized trial was conducted comparing 300 mL of CP with non-CP. Patients were ≥50 years, were symptomatic for <8 days, had confirmed RT-PCR or antigen test result for COVID-19 and had at least one risk factor for severe COVID-19. The primary endpoint was the highest score on a 5-point ordinal scale ranging from fully recovered (score = 1) or not (score = 2) on day 7, over hospital admission (score = 3), intensive care unit admission (score = 4) and death (score = 5) in the 28 days following randomization. Secondary endpoints were hospital admission, symptom duration and viral RNA excretion. ResultsAfter the enrolment of 421 patients and the transfusion in 416 patients, recruitment was discontinued when the countrywide vaccination uptake in those aged >50 years was 80%. Patients had a median age of 60 years, symptoms for 5 days, and 207 of 416 patients received CP therapy. During the 28 day follow-up, 28 patients were hospitalized and two died. The OR for an improved disease severity score with CP was 0.86 (95% credible interval, 0.59–1.22). The OR was 0.58 (95% CI, 0.33–1.02) for patients with ≤5 days of symptoms. The hazard ratio for hospital admission was 0.61 (95% CI, 0.28–1.34). No difference was found in viral RNA excretion or in the duration of symptoms. ConclusionsIn patients with early COVID-19, CP therapy did not improve the 5-point disease severity score.