Comparative analysis of human immune responses following SARS-CoV-2 vaccination with BNT162b2, mRNA-1273, or Ad26.COV2.S

Abstract

AbstractBackgroundThree SARS-CoV-2 vaccines, two based on mRNA, BNT162b2 and mRNA-1273, and one based on an adenovirus platform, Ad26.COV2.S, received emergency use authorization by the U.S. Food and Drug Administration in 2020/2021. These vaccines displayed clinical efficacy in initial studies against confirmed COVID-19 of 95.0%, 94.1%, and 66.9%, respectively.MethodsIndividuals receiving one of these vaccines were invited to participate in a prospective longitudinal comparative study of immune responses elicited by the three vaccines. In this observational cohort study, humoral responses were evaluated using a SARS-CoV-2 receptor-binding domain (RBD) ELISA and a SARS-CoV-2 virus neutralization assay at mean of 21-31 days and 45-63 days following each initial vaccination. IFN-γ ELISPOT assays were conducted with peripheral blood mononuclear cells obtained at a median of 45-63 days after each initial vaccination.ResultsThe two mRNA-based platforms elicited similar RBD ELISA responses and neutralizing antibody responses. The adenovirus-based vaccine elicited significantly lower RBD ELISA and SARS-CoV-2 virus neutralization activity. The mRNA-1273 vaccine elicited significantly higher spike glycoprotein-specific T cell responses than either the BNT162b2 or the Ad26.COV2.S vaccines.ConclusionsBoth mRNA based vaccines elicited higher magnitude humoral responses than Ad26.COV2.S and mRNA1273 elicited the highest magnitude of T cell response. Neutralizing antibody titers correlated with reported estimates of vaccine efficacy.Summary of key pointsWe compared antigen specific humoral and T cell responses following vaccination with BNT162b2, mRNA-1273, or Ad26.COV2.S. Both mRNA based vaccines elicited higher magnitude humoral responses than Ad26.COV2.S and mRNA1273 elicited the highest magnitude of T cell response.