Two novel SARS-CoV-2 surrogate virus neutralization assays are suitable for assessing successful immunization with mRNA-1273

Background: Due to large vaccination efforts with novel vaccines there is an increasing need for laboratory tests assessing successful immunizations with SARS-CoV-2 vaccines. Unfortunately classical neutralization assays are laborious, time-consuming and require an adequate biosafety level laboratory. Recently, convenient ELISA-based surrogate neutralization assays (sVNTs) for determination of neutralizing SARS-CoV-2 antibodies have been developed. Study Design: Our study compares the two novel ELISA-based SARS-CoV-2 surrogate neutralization assays cPass SARS-CoV-2 Surrogate Virus Neutralization Test Kit (GenScript Biotech, USA) and the TECO SARS-CoV-2 Neutralization Antibody Assay (TECOmedical, Switzerland) using 93 sera drawn from health care workers (HCVs) 2-3 weeks following the second vaccination with mRNA-1273 and 40 control sera from the pre-SARSCoV-2 era before 2019. Results: We found a sensitivity of 100% and 91,4% and a specificity of 100% and 100% for the GenScript assay and the TECO assay, respectively. Both sVNTs show a high correlation with anti-S IgG. Moreover, both sVNTs correlate well with each other. Conclusions: Surrogate neutralization assays based on the RBD as bait feature a high specificity and sensitivity for identifying humoral neutralizing activity in individuals vaccinated with the spike-based vaccine mRNA-1273. Although these assays appear well-suited for confirming successful vaccinations with spike-based vaccines, additional studies should compare both assays regarding other purposes such as screening COVID-recovered patients or individuals vaccinated with inactivated whole virus vaccines.

Automated summary

The study found that ELISA-based SARS-CoV-2 surrogate neutralization assays have high specificity and sensitivity in assessing successful immunizations with spike-based vaccine mRNA-1273, with a strong correlation with anti-S IgG and each other. Further research is recommended to compare these assays for other purposes, such as screening COVID-recovered patients or individuals vaccinated with inactivated whole virus vaccines.