Evaluation of a population-based prevention program against influenza among Swiss elderly people.

INTRODUCTION Influenza is a major cause of morbidity and mortality and occurs in epidemics in the winter. This study is an evaluation of a population-based prevention program against Influenza, implemented during autumn 2000 by the Health Department of the Canton of Vaud. METHODS A pre-intervention/post-intervention design was used. In June 2000 and March 2001, 4007 questionnaires were sent to two different stratified random samples of people aged 65 and over living in the Canton of Vaud, Switzerland. Univariate, bivariate and multivariate analyses were performed. RESULTS Vaccination coverage among people older than 65 was 58.0% in 1999 (95% CI: 56.2%-59.8%) and 58.4% (95% CI: 56.6%-60.2%) in 2000. A 6.5% significant increase in vaccination coverage was seen in the group of people aged 65 to 69 (p = 0.008). In the pre-intervention survey immunisation rates were 22.6% among people who had not consulted a physician, 59.2% among those who had consulted a physician once, and 73.2% among those who consulted twice or more (p = 0.001). These rates were respectively 30.8%, 58.0% and 75.1% (p = 0.001) in the post-intervention survey. CONCLUSIONS No global increase in Influenza vaccination coverage in the elderly population could be observed following a community based intervention in a Swiss Canton. However, the enhanced vaccination rates noted in the 65-69 years old group and in people who did not receive medical care are compatible with an effect of the campaign. Further increase in vaccination coverage may be obtained by diversification and repetition of such promotion campaigns.