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Published on: June 5, 2021
Randomized controlled trial transfusing convalescent plasma as post-exposure prophylaxis against SARS-CoV-2 infection
Shmuel Shoham1, Evan M Bloch1, Arturo Casadevall1
1Department of Medicine (S.S., K.G., D.T., P.B., J.Z., A.B., L.A., C.M.) Department of Pathology (E.B., A.T.), Department of Neurology (K.L., N.M., D.H., A.G., A.Y.) and the Department of Ophthalmology (DJ), The Johns Hopkins University School of Medicine, Baltimore, MD, Departments of Molecular Microbiology and Immunology (A.C., D.S., S.K., H.S.P., C.A.C., J.R.S., A.P. A.J.) and Epidemiology (B.L., D.S., D.J., S.E.,S.B., C.S.) The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, Mosaic Consulting Ltd., Israel (N.K.), Department of Medicine, Luminis Health, Annapolis, MD (B.M.), Department of Medicine, Section of Infectious Diseases, Baylor College of Medicine, Houston, TX (Y.F), Department of Emergency Medicine, Rhode Island Hospital/Brown University, Providence, RI (A.L.), Division of Infectious Diseases/Department of Medicine, Georgetown University Medical Center, Washington, DC (S.K.), Division of Allergy and Immunology, Department of Medicine (G.M.), and Department of Pathology (T.G.), Northshore University Health System, Evanston, IL, Department of Medicine, Division of Infectious Diseases University of Cincinnati, Cincinnati, OH (M.H.), Department of Medicine, Division of Infectious Diseases, University of California, Irvine, Irvine, CA (D.F.), Department of Medicine, Division of Infectious Diseases, University of California, Los Angeles, Los Angeles, CA (J.S.), Department of Medicine, Division of Infectious Diseases (E.C.) and Department of Pathology (E.A.), University of California, San Diego, San Diego, CA, Department of Medicine, Division of Hematology and Oncology, University of Massachusetts, Worchester, MA (J.G.), Department of Medicine, Division of Infectious Diseases, University of Miami Miller School of Medicine, Miami, FL (SA), Department of Medicine, University of Rochester, Rochester, NY (MZ), Department of Neurology, University of Utah, Salt Lake City, UT (J.R.S), Department of Medicine, Division Critical Care Medicine, University of Texas Health, Houston, TX (B.P.), Department of Emergency Medicine Wayne State University, Detroit, MI (J.P.), Danbury Hospital (P.B.), Norwalk Hospital (J.H.), Vassar Brothers Medical Center, Nuvance Health, Poughkeepsie, NY (VC) and University of Vermont (J.P., W.R., M.E.C.), Nuvance Health, Danbury, CT, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health Baltimore, MD (O.L.).
Background:
The efficacy of SARS-CoV-2 convalescent plasma (CCP) for preventing infection in exposed, uninfected individuals is unknown. We hypothesized that CCP might prevent infection when administered before symptoms or laboratory evidence of infection.
Methods:
This double-blinded, phase 2 randomized, controlled trial (RCT) compared the efficacy and safety of prophylactic high titer (≥1:320) CCP with standard plasma. Asymptomatic participants aged ≥18 years with close contact exposure to a person with confirmed COVID-19 in the previous 120 hours and negative SARS-CoV-2 test within 24 hours before transfusion were eligible. The primary outcome was development of SARS-CoV-2 infection.
Results:
180 participants were enrolled; 87 were assigned to CCP and 93 to control plasma, and 170 transfused at 19 sites across the United States from June 2020 to March 2021. Two were excluded for SARS-CoV-2 RT-PCR positivity at screening. Of the remaining 168 participants, 12/81 (14.8%) CCP and 13/87 (14.9%) control recipients developed SARS-CoV-2 infection; 6 (7.4%) CCP and 7 (8%) control recipients developed COVID-19 (infection with symptoms). There were no COVID-19-related hospitalizations in CCP and 2 in control recipients. There were 28 adverse events in CCP and 58 in control recipients. Efficacy by restricted mean infection free time (RMIFT) by 28 days for all SARS-CoV-2 infections (25.3 vs. 25.2 days; p=0.49) and COVID-19 (26.3 vs. 25.9 days; p=0.35) were similar for both groups.
Conclusion:
In this trial, which enrolled persons with recent exposure to a person with confirmed COVID-19, high titer CCP as post-exposure prophylaxis appeared safe, but did not prevent SARS-CoV-2 infection.
Trial Registration:
Clinicaltrial.gov number NCT04323800 .

