(HealthDay News) — COVID-19 convalescent plasma administered to mostly unvaccinated outpatients within nine days after symptom onset reduced the risk of progression of COVID-19 leading to hospitalization, according to a study published online March 30 in the New England Journal of Medicine.
David J. Sullivan, M.D., from Johns Hopkins University in Baltimore, and colleagues compared the efficacy and safety of COVID-19 convalescent plasma, as compared with control plasma, in a double-blind, randomized, controlled trial involving symptomatic adults (≥18 years of age) who had tested positive for severe acute respiratory syndrome coronavirus 2. Participants were enrolled within eight days after symptom onset and received a transfusion within one day after randomization. A total of 1,181 participants enrolled from June 3, 2020 through Oct. 1, 2021, received a transfusion.
The researchers found that the primary outcome of COVID-19-related hospitalization within 28 days occurred in 2.9 percent of the 592 participants who received convalescent plasma and in 6.3 percent of the 589 participants who received control plasma (absolute risk reduction, 3.4 percent; 95 percent confidence interval, 1.0 to 5.8; P = 0.005), corresponding to a 54 percent reduction in relative risk. Since 53 of the 54 participants with COVID-19 who were hospitalized were unvaccinated and one was partially vaccinated, evidence of efficacy in vaccinated participants could not be inferred. Sixteen grade 3 or 4 adverse events occurred in participants who were not hospitalized (seven and nine in the convalescent and control plasma groups, respectively).
“These recent acknowledgements of high-titer convalescent plasma’s benefit in treating early-stage COVID-19 — in conjunction with our peer-reviewed findings — should encourage clinicians to keep it as a viable therapy option for outpatients,” Sullivan said in a statement.
The study was partially funded by Octapharma.