Journal of Neurology | 2021
SARS-CoV-2 antibody seroprevalence in a large neuroimmunological patient cohort
Abstract
The safety of patients with neuroimmunological conditions such as multiple sclerosis (MS) during the current SARSCoV-2 pandemic has been a subject of major debate [1] and an accurate estimation of the burden of SARS-CoV-2 infection is pivotal. However, given the high prevalence of asymptomatic patients, the imperfect sensitivity of polymerase chain reaction (PCR) assays performed at a single time point, and limited testing capacity, the true number of SARS-CoV-2 infections likely exceeds the reported one. Serosurveys for SARS-CoV-2 antibodies (Abs) have so far only been reported for few neuroimmunological patient cohorts and often with only suboptimal assays [2, 3]. Here, we investigate the seroprevalence of SARS-CoV-2 Abs among neuroimmunology outpatient clinic patients from May 14th to September 30th, 2020, by two different assays and compare it to the seroprevalence of the general population. Further, precautionary health behavior was assessed to understand how possible overor under-cautious demeanor may affect seroprevalence. Of all patients who were admitted to the neuroimmunology outpatient clinic of LMU Hospital in Munich, Germany, during mentioned period, 509 gave written informed consent to participate in the study. A serum sample for SARS-CoV-2 antibody serology was taken from all included patients. Clinical data were retrospectively obtained using structured documentation of routine clinical data. Precautionary health behavior data was acquired from a digital analyzable, paper-based questionnaire (Online Resource 1) which was answered by 474 out of 509 included patients. In the questionnaire, adherence to official recommendations concerning curfew, hygiene recommendations, and reduction of social contacts during and after the lockdown in Germany in spring 2020 (calendar weeks 12–19) was enquired by symmetrical, balanced Likert scales ranging from 1 (“not at all”) to 5 (“very much”), respectively. Each serum sample was tested for SARS-CoV-2 Ab by two assays at the Institute of Laboratory Medicine (LMU Hospital): Elecsys® Anti-SARS-CoV-2 electrochemiluminescence immunoassay system measuring pan-Immunoglobulin (ECLIA, Roche-Diagnostics, Basel, Switzerland; hereafter Ro-pan-Ig) and Anti-SARS-CoV-2 enzyme-linked immunosorbent assay measuring IgG only (ELISA, EUROIMMUN, Lübeck, Germany; hereafter Eu-IgG) [4]. While Ro-pan-Ig only detects antibodies against the SARS-CoV-2 nucleocapsid antigen, Eu-IgG exclusively binds Abs to the receptor binding domain (RBD). According to the manufacturer, Ro-pan-Ig has 99.5% sensitivity and 99.8% specificity ≥ 14 days after a positive polymerase chain reaction (PCR) assay, respectively; the Eu-IgG sensitivity was 94.4% and specificity 99.6% [4]. Joachim Havla and Tania Kümpfel contributed equally.