Changes in the Adaptive Cellular Repertoire after Infection with Different SARS-CoV-2 VOCs in a Cohort of Vaccinated Healthcare Workers.

Publication date: Feb 23, 2024

Currently approved vaccines are highly effective in protecting against hospitalization and severe COVID-19 infections. How pre-existing immunity responds to new variants with mutated antigens is crucial information for elucidating the functional interplay between antibodies and B and T cell responses during infection with new SARS-CoV-2 variants. In this study, we monitored the dynamics and persistence of the immune response versus different SARS-CoV-2 variants of concern that emerged during the pandemic period (2021-2022) in a cohort of vaccinated healthcare workers, who experienced breakthrough infection in the Pre-Delta, Delta, and Omicron waves. We evaluated both the humoral and cell-mediated responses after infection. We also evaluated the anti-SARS-CoV-2 antibodies levels produced by infection in comparison with those produced after vaccination. Our results highlighted that the immune response against the Delta VOC mainly involved an adaptive humoral and switched memory B cells component, even 3 months after the last vaccine dose, conversely showing a high percentage of depleted adaptive T cells. Omicron infections triggered a consistent production of non-vaccine-associated anti-N antibodies, probably to balance the spike epitope immune escape mechanisms. Our results suggest a direct dependence between the VOC and different humoral and B and T cell balances in the post-infection period, despite the administration of a different number of vaccine doses and the elapsed time since the last vaccination.

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Concepts Keywords
Covid cell-mediated immunity
Depleted HCWs
Hospitalization humoral immunity
Vaccine SARS-CoV-2 VOCs


Type Source Name
disease MESH Infection
disease VO vaccinated
disease VO effective
disease MESH COVID-19
disease IDO cell
disease IDO immune response
disease MESH breakthrough infection
disease VO vaccination
disease VO vaccine dose
disease IDO production
disease VO vaccine
drug DRUGBANK Isoxaflutole
disease VO time
disease VO organization
disease MESH emergency
disease VO immunization
disease IDO host
drug DRUGBANK Coenzyme M
disease VO population
disease VO vaccine efficacy
disease MESH viral infection
disease VO Comirnaty
disease IDO blood
disease MESH Sore throat

Original Article

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