ABSTRACT
OBJECTIVE: To calculate the impact of different interventions on the rates of anti-flu vaccination in people aged 65 and over. DESIGN: Ecological study with analytical components. SETTING: Health centres and clinics in two health areas in the Community of Valencia. PATIENTS AND OTHER PARTICIPANTS: Care units, characterised by their coverage of stable nuclei of 500 or more people, total population of 415,172 inhabitants. INTERVENTIONS: Use of the communication media, personal invitations by post and telephone; follow-up of activity, discussion of results, external evaluations; registration of people to be vaccinated and prior order to nursing staff to vaccinate. MEASUREMENTS AND MAIN RESULTS: The coverage in quartiles of the previous season and the human resources per thousand inhabitants were the structural factors which best explained the vaccination rates. In the multivariate analysis, invitation by letter had relative risk (RR) of 1.062 (95% CI, 1.036-1.088); telephone call, RR 1.075 (95% CI, 1.021-1.132); discussion of external evaluations, RR 1.046 (95% CI, 1.024-1.068); and the order of vaccination to nursing staff, RR 1.056 (95% CI, 1.025-1.088). All these were associated with greater coverage. The absolute difference in coverage achieved between the care units which invited people to be vaccinated by letter and phone, at which nurses vaccinated directly, and which discussed external evaluations, and the units which did not perform these above activities, was 14 points (95% CI, 13.3-14.5), independently of the other factors. CONCLUSIONS: The previous year's coverage, human resources, invitation by letter or phone, the order to nursing to vaccinate and the discussion of external evaluations, were all associated, independently, with higher rates of vaccination.