Kinetics of the humoral immune response induced by the BNT162b2 against the SARS-CoV-2 variants

ABSTRACT

Introduction. The circulation of SARS-CoV-2 virus variants raises concerns about their potential evasion of the immune response and associated clinical consequences. Decay in the magnitude of the immune response over time after completion of the vaccination schedule has been evidenced. The aim of this study was to evaluate the kinetics of neutralizing antibodies after vaccination and the impact of circulating variants. Materials and methods. Prospective longitudinal study' with a cohort of 60 Colombian adults' who received the complete BNT162b2 vaccine schedule' and were followed for 6 months to determine the kinetics of antibodies. Plaque reduction neutralization assays were performed with live virus' using the B.1 lineage (D614G)' and the Gamma' Alpha' Delta' Mu and Omicron variants of the SARS-CoV-2 virus. Results. Neutralizing capacity against all variants was observed in all individuals after 1 month of vaccination;however' a progressive decrease in neutralizing capacity was observed after 3 and 6 months. Compared to the B.1 lineage' the neutralizing response against the Delta' Mu and Omicron variants presented the greatest decrease' evidencing their immune escape capacity' followed by the Gamma and Alpha variants. The decrease in antibody titers was more evident in men older than 40 years. Conclusions. Despite the safety and effectiveness of the vaccines' it is important to improve and monitor them in order to improve the protective response they can offer.