Coronavirus Disease 2019 Convalescent Plasma Outpatient Therapy to Prevent Outpatient Hospitalization: A Meta-Analysis of Individual Participant Data From 5 Randomized Trials
Adam C. Levine, Yuriko Fukuta, Moisés A. Huamán, Jiangda Ou, Barry Meisenberg, Bela Patel, James H. Paxton, Daniel F. Hanley, Bart Rijnders, Arvind Gharbharan, Casper Rokx, Jaap Jan Zwaginga, Andrea Alemany, Oriol Mitjà, Dan Ouchi, Pere Millat-Martínez, Valerie Durkalski‐Mauldin, Frederick K. Korley, Larry J. Dumont, Clifton W. Callaway, Romina Libster, Gonzalo Pérez Marc, Diego Wappner, Ignacio Esteban, Fernando P. Polack, David Sullivan
Abstract
BACKGROUND: Outpatient monoclonal antibodies are no longer effective and antiviral treatments for coronavirus disease 2019 (COVID-19) disease remain largely unavailable in many countries worldwide. Although treatment with COVID-19 convalescent plasma (CCP) is promising, clinical trials among outpatients have shown mixed results. METHODS: We conducted an individual participant data meta-analysis from outpatient trials to assess the overall risk reduction for all-cause hospitalizations by day 28 in transfused participants. Relevant trials were identified by searching Medline, Embase, medRxiv, World Health Organization COVID-19 Research Database, Cochrane Library, and Web of Science from January 2020 to September 2022. RESULTS: Five included studies from 4 countries enrolled and transfused 2620 adult patients. Comorbidities were present in 1795 (69%). The virus neutralizing antibody dilutional titer levels ranged from 8 to 14 580 in diverse assays. One hundred sixty of 1315 (12.2%) control patients were hospitalized, versus 111 of 1305 (8.5%) CCP-treated patients, yielding a 3.7% (95% confidence interval [CI], 1.3%-6.0%; P = .001) absolute risk reduction and 30.1% relative risk reduction for all-cause hospitalization. The hospitalization reduction was greatest in those with both early transfusion and high titer with a 7.6% absolute risk reduction (95% CI, 4.0%-11.1%; P = .0001) accompanied by at 51.4% relative risk reduction. No significant reduction in hospitalization was seen with treatment >5 days after symptom onset or in those receiving CCP with antibody titers below the median titer. CONCLUSIONS: Among outpatients with COVID-19, treatment with CCP reduced the rate of all-cause hospitalization and may be most effective when given within 5 days of symptom onset and when antibody titer is higher.