Comparative Statistical Analysis between Neutralization Assays in Vaccine Immunogenicity Assessments

SARS-CoV-2 led to the swift development of vaccines, and neutralization assays played a crucial role in assessing their effectiveness. A post-hoc analysis of a Phase I/II trial evaluated the immunogenicity of a bivalent SARS-CoV-2 protein vaccine. We assessed vaccine immunogenicity using live virus neutralization assays (LVNA) and pseudotyped virus neutralization assays (PVNA) to measure antibody responses against different variants, including Alpha, Beta, and Delta. Various statistical techniques, including correlation coefficients, regression models, and Bland–Altman plots, were employed to assess the relationship between antibody titers from the two assays. The study analyzed 324 samples for Alpha and Beta variants and 505 for Delta. PVNA demonstrated over 90% sensitivity and specificity for LVNA across all variants, with accuracy rates of 98.8% for Alpha, 99.1% for Beta, and 94.3% for Delta. The Pearson correlation between PVNA and LVNA was strong for Alpha (r = 0.9614), Beta (r = 0.9517), and Delta (r = 0.9072). Bland-Altman plots and Kernel density plots indicated good agreement between PVNA and LVNA. PVNA and LVNA showed a strong correlation, suggesting that PVNA is a reliable alternative to LVNA for assessing vaccine effectiveness. PVNA's high sensitivity and specificity make it valuable for monitoring immune responses.