Understanding Adaptive Immune Response After COVID-19 Vaccination Boosters to Improve Vaccination Strategies in Vulnerable Groups.

"Whole blood and serum samples will be longitudinally collected at the moment of the administration of the booster doses (T0) and three weeks after the booster doses (T1). Possible further time points will be collected within 2 years, based on the National recommended future vaccination regimens.~Biological samples will be used for the following exams:~* Cellular immunity characterization~ * T- and B-cells Immunophenotype.~ * Specific T-cell response.~ * In vitro specific B-cells characterization.~ * Antibody-dependent cellular cytotoxicity.~* Humoral response characterization~ * Serology assays.~ * Avidity assay.~ * Neutralization assays with different SARS-CoV-2 variants.~ * Presence of specific or cross-reactive antibodies for common hCoV.~* Genetic and epigenetic analysis"