Decline in influenza-associated mortality among Dutch elderly following the introduction of a nationwide vaccination program

With a retrospective nationwide cohort study in the Netherlands over 1992–2003, using mortality and viral surveillance data, the aim was to assess by means of rate difference methods the influenza-associated mortality in the elderly before and after the introduction of a nationwide influenza vaccination program in 1996 (vaccination coverage raised from below 50 to 80%). The average annual influenza-associated mortality declined in the years before and after the introduction from 131 to 105 per 100,000 persons (relative risk 0.80). The decline was largest in the age group 65–69 years (relative risk 0.54) and less in those aged 75 years and older. Validation by Serfling-type regression analysis revealed similar results. In conclusion, routine influenza vaccination among Dutch elderly was associated with a significant decrease in influenza-associated mortality, notably in those aged 65–69 years.