High but Short-lived anti-SARS-CoV2 neutralizing, IgM, IgA, and IgG levels among mRNA-vaccinees compared to naturally-infected participants (original) (raw)

1.BackgroundWaning of protection against emerging SARS-CoV-2 variants by pre-existing antibodies elicited due to current vaccination or natural infection is a global concern. Whether this is due to waning of immunity to SARS-COV-2 remains unclear.AimWe aimed to investigate dynamics of antibody isotype responses among vaccinated naïve (VN) and naturally infected (NI) individuals.MethodsWe followed up antibody levels in COVID-19 mRNA-vaccinated subjects without prior infection (VN, n=100) at two phases: phase-I (P-I) at ∼1.4 and phase-II (P-II) at ∼5.3 months. Antibody levels were compared to those of unvaccinated and naturally infected subjects (NI, n=40) at ∼1.7 (P-1) and 5.2 (P-II) months post-infection. Neutralizing antibodies (NTAb), anti-S-RBD-IgG, -IgM, and anti-S-IgA isotypes were measured.ResultsVN group produced significantly greater antibody responses (p<0.001) than NI group at P-I except for IgM. In VN group, a significant waning in antibody response was observed in all...