The irremediable ageing of the world population, the aged-related increasing in the prevalence of infectious diseases the fear of any influenza pandemic rife have recently led the European Union Geriatric Medicine Society (EUGMS) et the International Association of Geriatric and Gerontology European Regions (IAGG-ER) of establishing vaccine recommendations dedicated to individuals aged of 60 years or above and promoting a life-course vaccination programme. This approach is mainly motivated by the herd immunity-associated effect on the epidemiology of infectious diseases observed within the adult and old adult population. This review (1) after a presentation of the concept and its demonstrated beneficial effects; (2) will detail that herd immunity acts with adverse effects on the epidemiology of the infectious diseases in the adult and aged individual population; (3) in order to demonstrate that maintaining a vaccine pressure in every age groups is imperative.