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

      Klein, Matthew N; Wang, Elizabeth Wenqian; Zimand, Paul; Beauchamp, Heather; Donis, Caitlin; Ward, Matthew D; Martinez-Hernandez, Aidaelis; Tabatabai, Ali; Baddley, John W; Bloch, Evan M; et al. (BMJ Publishing Group, 2021-04-23)
      Aims: While the SARS-CoV-2 pandemic may be contained through vaccination, transfusion of convalescent plasma (CCP) from individuals who recovered from COVID-19 (CCP) is considered an alternative treatment. We investigate if CCP transfusion in patients with severe respiratory failure increases plasma titres of SARS-CoV-2 antibodies and improves clinical outcomes. Methods: Patients with COVID-19 (n=34) were consented for CCP transfusion and serial blood draws pretransfusion and post-transfusion. Plasma SARS-CoV-2 antireceptor binding domain (RBD) IgG and IgM titres were measured by ELISA serially, and compared with serial plasma titre levels from control patients (n=68). The primary outcome was survival at 30 days, and secondary outcomes were length of ventilator and/or extracorporeal membrane oxygenation (ECMO) support, length of stay (LOS) in the hospital and in the intensive care unit (ICU). Outcomes were compared with matched control patients (n=34). Kinetics of antibodies and clinical outcomes were compared using LOess regression and ORs, respectively. Results: Prior to CCP transfusion, 74% of patients were anti-RBD seropositive for IgG (median 1:3200), and 81% were anti-RBD IgM seropositive (median 1:320), while 16% were seronegative. The kinetics of antibody titres in CCP recipients were similar to controls. CCP recipients presented with similar survival, duration on ventilatory and/or ECMO support, as well as ICU and hospital LOS compared with controls. Conclusions: CCP transfusion did not increase the kinetics of SARS-CoV2 antibodies and did not result in improved clinical outcomes in patients with COVID-19 with severe respiratory failure, suggesting that CCP may not be indicated in this category of patients.
    • Performance of 4 Automated SARS-CoV-2 Serology Assay Platforms in a Large Cohort Including Susceptible COVID-19-Negative and COVID-19-Positive Patients

      Ward, Matthew D; Mullins, Kristin E; Pickett, Elizabeth; Merrill, VeRonika; Ruiz, Mark; Rebuck, Heather; Duh, Show-Hong; Christenson, Robert H (Oxford University Press, 2021-03-10)
      BACKGROUND: Anti-SARS-CoV-2 serological responses may have a vital role in controlling the spread of the disease. However, the comparative performance of automated serological assays has not been determined in susceptible patients with significant comorbidities. METHODS: In this study, we used large numbers of samples from patients who were negative (n = 2030) or positive (n = 112) for COVID-19 to compare the performance of 4 serological assay platforms: Siemens Healthineers Atellica IM Analyzer, Siemens Healthineers Dimension EXL Systems, Abbott ARCHITECT, and Roche cobas. RESULTS: All 4 serology assay platforms exhibited comparable negative percentage of agreement with negative COVID-19 status ranging from 99.2% to 99.7% and positive percentage of agreement from 84.8% to 87.5% with positive real-time reverse transcriptase PCR results. Of the 2142 total samples, only 38 samples (1.8%) yielded discordant results on one or more platforms. However, only 1.1% (23/2030) of results from the COVID-19-negative cohort were discordant. whereas discordance was 10-fold higher for the COVID-19-positive cohort, at 11.3% (15/112). Of the total 38 discordant results, 34 were discordant on only one platform. CONCLUSIONS: Serology assay performance was comparable across the 4 platforms assessed in a large population of patients who were COVID-19 negative with relevant comorbidities. The pattern of discordance shows that samples were discordant on a single assay platform, and the discordance rate was 10-fold higher in the population that was COVID-19 positive.
    • Validation of COVID-19 serologic tests and large scale screening of asymptomatic healthcare workers

      Mullins, Kristin E; Merrill, VeRonika; Ward, Matthew; King, Brent; Rock, Peter; Caswell, Mary; Ahlman, Mark; Harris, Anthony D; Christenson, Robert (Elsevier Inc., 2021-01-17)
      Objectives: Serologic testing for SARS-CoV-2 is an important element in the fight to slow the COVID-19 pandemic. This study aimed to validate two serologic tests for total (IgM, IgG, IgA) SARS-CoV-2 antibodies, (i) the Ortho-Clinical Diagnostics Anti-SARS-CoV-2 Total Antibody assay for the Vitros 5600 analyzers and (ii) a manual laboratory developed ELISA (FDA EUA pending), for use in parallel orthogonal testing of asymptomatic healthcare workers and affiliates of the University of Maryland Medical System. Design and Methods: Validation and verification of the two tests was performed using samples from hospitalized patients that were found to be PCR positive for SARS-CoV-2, samples pre-COVID-19, and samples from individuals with current/previous infections with other viruses. Healthcare workers and affiliates from across the University of Maryland Health System were provided testing free of charge and their results were reported as reactive or non-reactive if the two tests were concordance, or indeterminate if the results were discordant. Results: Validation testing found the Ortho Vitros test to be 100% (73/73) sensitive, and 99.3% (152/153) specific, while the UMMC ELISA was found to be 97.6% (204/209) sensitive and 100% (288/288) specific. Real world testing among 8399 healthcare workers found that 2.9% (247/8399) of healthcare workers were positive for anti- SARS-CoV-2 antibodies by both tests. An indeterminate rate of 1.1% (91/8399), in which one test reported reactive results, and one as non-reactive was also seen. Conclusions: Parallel orthogonal testing improves the positive and negative predictive value of serologic testing in populations with low prevalence. The use of an indeterminate result from parallel orthogonal testing allows for the follow-up and re-testing, which helps resolve discrepancies between assays.