The clinical linearity of the quantitative anti-S SARS-CoV-2 IgG II Quant assay was evaluated using five patient samples with elevated S-IgG values. Samples were measured at 1:2 dilutions and This study evaluated the persistence of IgM, IgA, and IgG to SARS-CoV-2 spike and nucleocapsid antigens up to 616 days since the onset of symptoms in a longitudinal cohort of 247 primary health care workers from Barcelona, Spain, followed up since the start of the pandemic. The study also assesses factors affecting antibody levels, including comorbidities and the responses to variants of BackgroundIgG anti-spike (S) antibodies arise after SARS-CoV-2 infection as well as vaccination. Levels of IgG anti-S are linked to neutralizing antibody titers and protection against (re)infection.MethodsWe measured IgG anti-S and surrogate neutralizing antibody kinetics against Wild Type (WT) and 4 Variants of Concern (VOC) in health care workers (HCW) 3 and 10 months after natural infection A total of 4290 samples from 393 convalescent COVID-19 and 916 COVID-19 negative individuals were analyzed. In convalescent individuals, SARS-CoV-2 antibodies followed a triphasic kinetic model with half-lives at month (M) 11–13 of 283 days (95% CI 231–349) for anti-N and 725 days (95% CI 623–921) for anti-RBD IgG, which stabilized at a median of 1.54 log BAU/mL (95% CI 1.42–1.67). The plot demonstrates that anti-SARS-CoV-2 antibody maturation is observed over several months following infection onset. (d) Similar apparent affinity data from blood draws following the first and second doses of Moderna vaccine (triangles, 18 samples, 8 patients) reveal that high anti-SARS-CoV-2 affinities were reached in a much shorter time. Testing was done for the presence of SARS-CoV-2-specific anti-spike IgM, IgG antibodies, and anti-nucleocapsid IgG antibodies. Weighted seropositivity was estimated along with the adjustment done for the sensitivity and specificity of the test used.FindingsThe data were collected from a total of 4,229 participants from the general population .

anti sars cov 2 igg kuantitatif