Prevalence and determinants of influenza vaccination in Australians aged 40 years and over - a national survey

Objectives: To determine influenza vaccination coverage in 2001 in Australian adults aged greater than or equal to40 years, assess awareness of and attitudes to influenza vaccine, factors associated with vaccination, and estimate uptake of free vaccine provided to those aged greater than or equal to65 years. Methods: National computer-assisted telephone interview (CATI) survey in October/November 2001. Results: Interviews were completed with 5,266 people aged greater than or equal to65 and 2,415 aged 40-64 years. Thirty per cent of selected households participated. Overall, 67% of respondents believed that the vaccine was somewhat to very effective in preventing influenza. Seventy-eight per cent of those aged greater than or equal to65 years reported influenza vaccination; 89% had received it free. Independent predictors of vaccination were: belief that influenza vaccine is effective in preventing influenza (OR=13.5, 95% Cl 10.6-17.2); and the presence of chronic disease (OR=1.6, 95% Cl 1.3-2.0). Overall, 24% of those aged 40-64 years were vaccinated; only 34% of those who met any of the criteria for vaccination (medical risk factor, at-risk occupation, or being Aboriginal or Torres Strait Islander) reported vaccination. Conclusions: Influenza vaccine coverage was high in those aged greater than or equal to65 years, but coverage of those at-risk aged 40-64 years remained suboptimal. Immunisation against influenza was influenced more by beliefs about the vaccine's effectiveness and existing medical risk factors, rather than socio-demographic factors such as gender and income.