This is an experimental study without drug and device, non-profit, single-center. The general objective of the project is to study how the adaptive immune response evolves against SARS-CoV-2 with repeated vaccination boosters and infections also in relation to the evolution of variations. This study will be relevant to frail populations who are the main targets of repeated vaccinations. Our project will benefit from the availability of a highly cohort characterized of vaccinated people, including cancer patients and elderly people, with prospective collection of samples for an in-depth evaluation of the evolution of the immune response with repeated exposure to doses of infection or vaccine. As part of the study, analyzes will be carried out on samples of patients enrolled in a manner prospective at the oncology departments of the IRCCS (Medical Oncology, Department of Radiotherapy advanced oncology and nuclear medicine) and elderly patients residing in retirement homes of the IRCCS. Patients will also be asked for consent to store any residual samples in the Tropica DITM Biobank.