#Influenza #vaccination post - #COVID19 expands vaccine-specific effector #CD4 T-cells and Tregs under positive influence of host trained innate #immunity
Abstract SARS-CoV-2 immunity and innate immune training may influence influenza vaccine immunogenicity . We investigated this in India . Adult volunteers with hybrid SARS-CoV-2 immunity were administered FluarixTM Tetra (GlaxoSmithKlein) 2022/2023 NH Vaccine in 2022. Significant induction of hemagglutinin inhibition-specific antibodies and polyfunctional central memory CD4+ T-cells (TCM) were observed 1-week post-vaccination with variable induction of CD8+T-cell and innate effectors. Vaccination also expanded Flu-specific regulatory T-cells (Treg), which negatively correlated with CD4 responses , highlighting vaccine immunogenicity may be subject to Treg dampening . FluarixTM did not boost SARS-CoV-2 immunity . However, SARS-CoV-2 -specific T-cell responses correlated positively with vaccine-induced T-cell responses. We evaluated trained immunity post-COVID-19 as a potential regulatory mechanism linking SARS-CoV-2 and heterologous vaccine immunogenicity . We observed, elevated fr...