Convalescent Plasma Reduces Endogenous Antibody Response in COVID-19: A Retrospective Cross-Sectional Study

Objective: The aim of this study is to investigate post-COVID-19 antibody titers in patients who received convalescent plasma (CP) in addition to standard-of-care treatment. Materials and Methods: Hospitalized COVID-19 patients who received CP in addition to standard care were retrospectively investigated. Patients who received CP with a recorded total COVID-19 antibody test result after treatment were included. From among hospitalized COVID-19 patients who received only standard care with a recorded total COVID-19 antibody test result, a control group matched for age, gender, and comorbidities was formed. Total COVID-19 antibody index levels were compared. Results: Thirty-three CP recipients were enrolled in the study. The control group consisted of 34 age-, gender-, and comorbiditymatched standard-care patients. Median total COVID-19 antibody index levels were significantly reduced in the CP group. Conclusion: Although CP therapy may have benefits for disease outcome, its potential ability to hamper long-term immunity may be a problem.