While more than 500,000 units of COVID-19 convalescent plasma (CCP) have been transfused in the United States alone, the use and efficacy has become controversial. The World Health Organization recently issued a recommendation that CCP should not be used outside of clinical trials. Almost all of the available randomized clinical trial data, however, are among individuals who were hospitalized. Two new trials evaluated the used of CCP as either prophylaxis or early treatment. In a double-blind randomized trial assessing whether high-titer CCP prevented infection among those who were highly-exposed but uninfected, 87 individuals received placebo control plasma and 81 individuals received CCP. There was no difference between the two trial arms among those who developed infection (14.9% control vs. 14.8% CCP). In a second randomized trial assessing whether high-titer CCP provided as an outpatient within nine days of symptom onset reduced hospitalizations in symptomatic adults, 589 individuals received placebo control plasma and 592 individuals received CCP. Hospitalization, the primary endpoint, occurred in 37 individuals in the control arm and 17 individuals in the intervention arm; thus, CCP reduced hospitalizations by 54% (p=0.004). Combined with other randomized trial data on the benefit of outpatient CCP, CCP should be considered for those at high-risk of hospitalization.
References:
- Sullivan DJ, Gebo KA, Shoham S, Bloch EM, et al. Randomized controlled trial of early outpatient COVID-19 treatment with high-titer convalescent plasma. MedRxiv 2021
- Shoham S,Bloch EM, Casadevall A, Hanley D, et al. Randomized controlled trial transfusing convalescent plasma as post-exposure prophylaxis against SAR-CoV-2 infection MedRxiv 2021
- Tobian A, Cohn CS, Shaz B. COVID-19 convalescent plasma. Blood; 2021 Oct 25
- WHO recommends against th use of convalescent plasma to treat COVID-19. WHO News Release Dec 7, 2021.
