Kinetics of SARS-CoV-2 antibody responses pre- and post- COVID-19 convalescent plasma transfusion in patients with severe respiratory failure: an observational case-control study

OBJECTIVES To investigate if COVID-19 convalescent plasma (CCP) transfusion in patients with severe respiratory failure will increase plasma levels of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) antibody titers while improving survival and clinical outcomes. DESIGN Observational, retrospective, control study of anti-Receptor binding domain (RBD) of SARS-CoV-2 IgG and IgM titers from serial plasma samples drawn before and after CCP administration. Clinical improvement in CCP recipients is assessed and compared to COVID-19 control patients. SETTING Patients hospitalized with severe COVID19, United States, between April 17 and July 19, 2020 PARTICIPANTS 34 patients hospitalized with severe or life threatening COVID-19 and who consented and received a CCP transfusion, 95 control patients with COVID-19 not transfused with CCP. 34 out the 95 control patients were matched for age, sex, and the level of respiratory support required. Patients less than 18 years old were excluded. MAIN OUTCOME MEASURES Serial trends of anti-RBD of SARS-CoV-2 IgG and IgM titers in CCP recipients are compared to those in control patients. The primary outcome is survival at 30 days, and the secondary outcomes are length of ventilatory and/or extracorporeal membrane oxygenation (ECMO) support, length of stay (LOS) in the hospital, and LOS in the ICU. RESULTS CCP transfusion occurred in 34 patients at a median of 12 days following COVID-19 symptom onset. Immediately prior to CCP transfusion, patients median anti-RBD SARS-CoV-2 IgG and IgM titers were 1:3200 (IQR, 1:50 to 1:9600) and 1:320 (IQR, 1:40 to 1:640) respectively. Following a Loess regression analysis, the kinetics and distribution of anti-RBD of SARS-CoV-2 IgG and IgM in plasma from CCP recipients were comparable to those from a control group of 68 patients who did not receive CCP. CCP recipients presented with similar survival, similar duration on ventilatory and/or ECMO support, as well as ICU and hospital LOS, compared to a matched control group of 34 patients. CONCLUSION In the present study, hospitalized COVID-19 patients with severe respiratory failure transfused with CCP presented with high titers of SARS-CoV-2 IgG antibodies before transfusion and did not show improved survival at 30 days. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial Observational study ### Funding Statement This study was funded by the University of Maryland School of Medicine Department of Pathology Funds and by the Biomedical Advanced Research and Development Authority (BARDA). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by the University of Maryland Baltimore Institutional Research Subject Review Board (Protocol HP-00092606). The investigators have followed all appropriate research reporting guidelines. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Upon request Data sources can be provided for results presented in the study