Bases des Recommandations vaccinales

Abstract

Le processus d’élaboration des recommandations vaccinales, fondé sur l’établissement de la balance entre les bénéfices et les risques, est un processus complexe et continu. Il fait appel à une expertise largement multidisciplinaire, prenant en compte des facteurs épidémiologiques, immunologiques, mais aussi sociaux, économiques et politiques. Il repose essentiellement sur des données épidémiologiques mais fait de manière croissante appel à des outils sophistiqués de modèlisation mathématique et d’évaluation médico-économique. Les décisions doivent intégrer des concepts mal définis tels que le prix accordé par notre société à la prévention d’un décès d’enfant ou plus largement à une année de vie sauvée, les niveaux de risque d’effets secondaires et de maladies acceptables ou l’aspect collectif de la stratégie vaccinale interférant avec la liberté de choix individuelle.

Once a new vaccine has been granted its licensing, a public health expertise is needed in order to support the decision regarding its possible inclusion within the national immunisation schedule. This analysis, based on an assessment of the benefits/risks balance and costs/effectiveness ratio, is a multidisciplinary exercise. Largely based on epidemiological and immunological expertises, it also requires biomathematical and economical inputs, if the long term consequences of the vaccination are to be taken into account. Indeed, the main drivers of the decision are the burden of the disease, the characteristics of the vaccine in term of effectiveness and safety, the cost of the vaccination, the feasibility of the adjunction of the vaccine in the schedule, the social demand for this vaccination and the positive or negative indirect effects of a large vaccination on the epidemiology of the disease, in addition to the direct protective effect for vaccinated individuals. New vaccines are generally characterised by a more limited epidemiological impact than older vaccines, in a context of growing requirements from our society regarding drugs, and especially vaccines, safety. Both the real and perceived benefits/risks balances for the more recent vaccines appear questionable. The possibility of detrimental epidemiological consequences of either insufficient vaccination coverage or serotype (or serogroup) replacement is another factor that makes the decision regarding vaccination strategies increasingly complex.