Late Breaking Abstract - Post-trial follow-up after a randomized clinical trial of COVID-19 convalescent plasma

Abstract

<b>Introduction:</b> In a recent randomized controlled trial (RCT), we showed that early administration of high-titer convalescent plasma (CP) against SARS-CoV-2 to mildly ill infected older adults reduced the progression of COVID-19 (Libster, R. et al. N Engl J Med 2021;384:610-8). However, CP may also have a long-term negative effect by down-regulating the inflammatory response (Acosta Ampudia Y. et al. Journal of Autoimmunity 2021; 118:102598). Our objective was to establish the long-term safety profile of COVID-19 CP and determine if its administration increases the risk for further acute respiratory infections (ARIs). <b>Methods:</b> All patients included in the intention to treat analysis were contacted between 7-11 months after randomization. The primary endpoint was the number of patients with ARIs. Secondary endpoints included time to first ARI, SARS-CoV-2 confirmed re-infection, all-cause mortality, adverse events, and persistence of COVID-19 symptoms. <b>Results:</b> 142 patients were included, with a retention rate of 92.8%. The median duration of follow-up was 10.4 months (IQR 1.63). No differences were observed in the number of patients with ARI (CP=11/72 and Placebo=9/70,p-value=0.678), the median time in months to first ARI (CP=8.63(IQR 7.13) vs Placebo=9.2(IQR 7.53), log-rank test p-value=0.63), total SARS-CoV-2 reinfections, adverse events, all-cause mortality and in the persistence of COVID-19 symptoms. These results remained stable in a subgroup analysis performed by modified intention to treat and SARS-CoV-2 S IgG titer in donor plasma. <b>Conclusions:</b> In this post-trial follow-up study, CP did not increase the risk for ARIs. To our knowledge, this is the first post-trial follow-up after a RCT of COVID-19 CP.