Objective: To define the overall rate of humoral responders patients after the second dose of RZV administration. Primary Endpoint: The rate of humoral responders will be defined as the percentage of patients showing ≥ 4 times of gE-specific IgG response (IU/mL) after the second dose (T1m) respect to baseline (T0) Secondary Objective 2.1: To define the overall increase of humoral response after the second dose of RZV administration. Secondary Objective 2.2: To characterize the immunogenicity induced by RZV vaccine in the different study cohorts (rheumatologic, oncologic, neurologic and hematologic patients) Secondary Objective 2.3: To evaluate the kinetics of humoral response during the first year after the vaccination Secondary Objective 2.4: To characterize gE-specific T cell mediated response elicited by RZV vaccination in overall patients Secondary Objective 2.5: Evaluation of the incidence of adverse reactions (AR) to the RZV vaccine, local and systemic, solicited and unsolicited, within the period of four weeks after the second dose of RZV. Secondary Objective 2.6: Evaluation of the incidence of reactivation of VZV cases after the second dose of RZV.