Correlation between a quantitative anti-SARS-CoV-2 IgG ELISA and neutralization activity

In the current COVID‐19 pandemic, a better understanding of the relationship between merely binding and functionally neutralizing antibodies is necessary to characterize protective antiviral immunity following infection or vaccination. This study analyzes the level of correlation between the novel quantitative EUROIMMUN Anti‐SARS‐CoV‐2 QuantiVac ELISA (IgG) and a microneutralization assay. A panel of 123 plasma samples from a COVID‐19 outbreak study population, preselected by semiquantitative anti‐SARS‐CoV‐2 IgG testing, was used to assess the relationship between the novel quantitative ELISA (IgG) and a microneutralization assay. Binding IgG targeting the S1 antigen was detected in 106 (86.2%) samples using the QuantiVac ELISA, while 89 (72.4%) samples showed neutralizing antibody activity. Spearman's correlation analysis demonstrated a strong positive relationship between anti‐S1 IgG levels and neutralizing antibody titers (r s = 0.819, p
Highlights A new quantitative anti‐S1 assay (EUROIMMUN Anti‐SARS‐CoV‐2 QuantiVac ELISA IgG) was compared to a microneutralization assay.The QuantiVac ELISA showed a high level of qualitative overall agreement and a strong quantitative correlation with the results of neutralization testing.The QuantiVac ELISA has the potential to predict protective immunity against SARS‐CoV‐2 folllowing infection or vaccination.