Effectiveness of age-based strategies to increase influenza vaccination coverage among high risk subjects in Madrid (Spain).

We aim to assess the effectiveness of age-based strategies to increase influenza vaccination coverage among high risk subjects. To do so, we describe and compare the influenza vaccination coverage in the 2006/2007 campaign between the Autonomous Community of Madrid (ACM), where in year 2005 the recommendation was extended by 5 years to cover all those aged 60 and over, and other regions of Spain where the universally recommended age was 65 years and above. We used individualized secondary data provided by two surveys carried out in 2007 in ACM and in the rest of Spain. The total number of subjects included in the study was 21,948. For the 60-64 years age group influenza vaccination coverage was significantly higher 40.1% (CI 95% 36.4-43.8) in ACM residents than among residents in the Rest of Spain 29.1% (CI 95% 24.5-33.7). The difference in vaccine uptake was even greater, 59% (CI 95% 51.8-66.2) vs. 43.5%(CI 95% 34.3-52.7), when we compared subjects who suffered a chronic condition, which represents an indication for the anti-influenza vaccination. The results of the multivariate analysis show that the probability of a subject aged 60-64 living in ACM of being vaccinated was almost two times higher (OR 1.95 CI 95% 1.46-2.61) than a person of the same age who lived in a region of Spain where the universal recommendation for influenza vaccine started at 65 years. In conclusion, the available evidence indicates the effectiveness of age-based strategies to increase influenza vaccination coverage among high risk subjects aged 60-64 years in our population.