A detailed two-month follow-up study of 351 COVID-19 patients treated with convalescent plasma therapy at Houston Methodist Hospital concludes that those patients receiving convalescent plasma with a very high antibody content against the SARS-CoV-2 virus – also known as high titer – within two days of hospitalization were significantly more likely to survive the infection.


“These findings essentially provide the optimal roadmap for convalescent plasma treatment and are especially significant as COVID-19 cases continue to increase around the country,” said James M. Musser, M.D., Ph.D., chair of the Department of Pathology and Genomic Medicine at Houston Methodist and corresponding author of the study.  “Our work shows the exact parameters that should be used to make convalescent plasma maximally effective for patients.”


About 10,000 patients each week are being treated with convalescent plasma nationwide. Houston Methodist has treated 544 COVID-19 patients with convalescent plasma since March 28, when it became the first academic medical center in the nation to infuse critically ill patients with plasma donated from recovered patients. Physician researchers continue to carefully track convalescent plasma’s effect on COVID-19 patients admitted to Houston Methodist’s system of eight hospitals.


This most recent study definitively confirms and extends scientific evidence presented earlier in an interim analysis published in August in the American Journal of Pathology, which found that the century-old use of convalescent plasma donated by survivors of the illness is safe and effective, and also significantly decreases mortality. The investigators also show that transfusion of very high-titer convalescent plasma has the maximum beneficial effect if given within 44 hours of hospitalization.


The latest study, titled “Significantly decreased mortality in a large cohort of COVID-19 patients transfused early with convalescent plasma containing high titer anti-SARS-CoV-2 spike protein IgG,”  was led by principal investigator Eric Salazar, M.D., Ph.D., assistant professor of Pathology and Genomic Medicine with the Houston Methodist Hospital and Research Institute. The study is published today in the American Journal of Pathology.


In addition to Musser and Salazar, other collaborators from Houston Methodist on this study were Paul A. Christensen, Edward A. Graviss, Duc T. Nguyen, Brian Castillo, Jian Chen, Bevin Valdez Lopez, Todd N. Eagar, Xin Y, Picheng Zhao, John Rogers, Ahmed Shehabeldin, David Joseph, Christopher Leveque, Randall J. Olsen, David W. Bernard, and Jimmy Gollihar of the US Army Research Laboratory-South, University of Texas Austin.


This study was supported by funding from the Fondren Foundation, Houston Methodist Hospital, Houston Methodist Research Institute and Houston Methodist Infectious Diseases Research Fund