[Vaccination programmes]

Immunization is a highly cost-effective intervention that saves many lives. Its objective is to control and eliminate vaccine-preventable diseases (when the characteristics of the disease and the vaccine make it possible), resulting in improvements in the health of the population. In Spain, the first vaccination schedule was introduced in 1975 and currently coverages > 95% are achieved in children aged < 2 years of age. Before deciding to introduce a vaccination programme in a community or country, a series of aspects should be considered, including the disease burden in the population, the effectiveness and safety of the vaccine, the changes in the dynamics of the infection when the vaccine is introduced, the cost-effectiveness of the vaccine, the theoretical potential of elimination/eradication of the disease and the existence of other preventive or therapeutic measures. Once the programme has been introduced it should be subject to evaluation, considering aspects such as the coverage, effectiveness, safety and the impact on the population. This work defines different vaccination strategies for three diseases for which efficacious and safe vaccines are available: hepatitis A, influenza and varicella.