Study of immune responses after seasonal influenza and pandemic variant H1N1 vaccination in a healthcare worker population. - FLU-HOP

PRIMARY OUTCOME: Main Objective: The primary objective is to evaluate the intensity of humoral and cellular immune responses to the H1N1 variant (H1N1) vaccine in the healthcare worker population, taking into account age and prior influenza vaccinations. Primary endpoint(s): Humoral responses against the different circulating layers (seasonal and H1N1v) will be assessed using hemagglutination tests. The criteria for efficacy in inducing immune responses will follow the recommendations for influenza vaccines: - Increase in GMT (>2.5 pre-vaccination value); - Seroconversion rate (>40%); - Seroconversion rate (>60%). Secondary Objective: ? To analyze the quality of residual and vaccine-induced cellular and humoral immune responses to seasonal influenza viruses according to age and prior seasonal vaccinations; to determine the cross-reactivity of cellular and humoral responses according to age and prior seasonal vaccinations; to evaluate the tolerability of seasonal and pandemic vaccines; to assess the occurrence and severity of influenza episodes during the 2009/2010 season according to the age of the population and to correlate influenza events with the immunological results of vaccination; to assess hospital staff's perception of influenza vaccination in the current context of the H1N1v pandemic. INCLUSION CRITERIA: - Volunteers - Age = 20 years - For women of childbearing age: under effective contraception (pill or IUD) Are the trial subjects under 18? no Number of subjects for this age range: F.1.2 Adults (18‐64 years) yes F.1.2.1 Number of subjects for this age range F.1.3 Elderly (>=65 years) yes F.1.3.1 Number of subjects for this age range