Analysis of humoral and cellular immune activation up to 21 months after heterologous and homologous COVID-19 vaccination.

ABSTRACT: To address the COVID-19 pandemic, diverse vaccination strategies, including homologous and heterologous schedules, were employed to enhance immune protection. This study evaluates the long-term humoral and cellular immune responses in individuals vaccinated with homologous (ChAdOx1-S/ChAdOx1-S [ChAd/ChAd]) and heterologous (ChAdOx1-S/BNT162b2 [ChAd/BNT]) schedules, followed by a third-dose mRNA booster (BNT162b2 [BNT] or mRNA-1273). Anti-Spike IgG titers were measured at 9-, 12-, and 21-months post-primary vaccination (corresponding to 3-, 6-, and 15-months post-booster), while SARS-CoV-2-specific B- and T-cell responses were assessed at 21-months post-booster. Antibody titers declined by 12-months post-primary vaccination, regardless of the third dose administered, and increased significa

SUBMITTER: Torre D 

PROVIDER: S-EPMC12081374 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature