![]() The majority of the vaccines in use are based on the S protein, with the goal of eliciting protective neutralizing antibodies the rest are based on whole inactivated SARS-CoV-2 ( Dai and Gao, 2021 Forni and Mantovani, 2021). There are currently 294 candidate SARS-CoV-2 vaccines in development (status August 03, 2021) ( World Health Organization, 2021) and, of these, 17 are currently in early, limited, or fully approved use (status July 07, 2021) ( Gavi, 2021). This information is crucial to support diagnosis, contact tracing, epidemiological studies, and vaccine development to enable characterization of pre-vaccination immune status and vaccine-induced immune response ( Galipeau et al., 2020 Ernst et al., 2021 Zhu et al., 2020 Widge et al., 2021). Several studies have observed median seroconversion at day 10–13 after symptom onset for IgM and day 12–15 for IgG, with maximum seroconversion for IgM, IgG, and total antibodies occurring at week 2–3, week 2–4, and around week 2, respectively ( Long et al., 2020 Zhao et al., 2020 Lou et al., 2020 Young et al., 2020).Įmergence of the COVID-19 pandemic has resulted in an urgent and unmet need to develop reliable serological tests to determine past exposure to the virus and the seroprevalence in a given population ( Kontou et al., 2020). The chronological order of appearance and levels of IgM and IgG seems to be highly variable and often simultaneous ( To et al., 2020 Long et al., 2020 Zhao et al., 2020). Studies into the kinetics of antibodies to SARS-CoV-2 are rapidly emerging and, both immunoglobulin M (IgM) and G (IgG) antibodies have been detected as early as day 1 after symptom onset ( Guo et al., 2020). Understanding the dynamics of the antibody response to the virus is critical in establishing a relevant time window to use for serology testing ( Galipeau et al., 2020). Each S monomer consists of two subunits, S1 and S2, which mediate receptor binding (via the receptor-binding domain located in S1) and membrane fusion, respectively, leading to entry into host cells ( Tang et al., 2020 Wrapp et al., 2020 Ou et al., 2020).įollowing SARS-CoV-2 infection, the host mounts an immune response against the virus, including production of specific antibodies against viral antigens ( Galipeau et al., 2020). The most prominent protein component on the viral surface is the S glycoprotein – a large transmembrane protein that assembles into trimers to form the distinctive surface spikes of coronaviruses ( Walls et al., 2020 Tang et al., 2020). SARS-CoV-2 is an enveloped, single-stranded RNA virus of the family Coronaviridae its genome encodes 16 nonstructural proteins and four structural proteins: spike (S), envelope (E), membrane (M), and nucleocapsid (N) ( Naqvi et al., 2020). ![]() In December 2019 a novel coronavirus emerged ( Chan et al., 2020), named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the causative agent of the disease, COVID-19 ( Wu et al., 2020 World Health Organization, 2020). Therefore, the Elecsys Anti-SARS-CoV-2 S assay demonstrated a reliable performance across various sample populations for the detection of anti-S antibodies. The Elecsys Anti-SARS-CoV-2 S immunoassay had significantly higher sensitivity (≥14 days post-PCR) compared with the ARCHITECT SARS-CoV-2 IgG (98.70% vs 87.01% ), iFlash-SARS-CoV-2 IgG (100.00% vs 93.42% ) and IgM (100.00% vs 35.53% ), and EUROIMMUN Anti-SARS-CoV-2 IgG (98.26% vs 93.91% ) assays. For specificity and sensitivity analyses, 7880 presumed negative pre-pandemic samples and 827 SARS-CoV-2 PCR-confirmed single or sequential samples from 272 different patients were tested, respectively. We evaluated the assay performance using samples from seven sites in Germany, Austria, and Switzerland. ![]() The Elecsys® Anti-SARS-CoV-2 S immunoassay (Roche Diagnostics International Ltd, Rotkreuz, Switzerland) has been developed for the detection of antibodies to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein. ![]()
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