Influenza vaccinations in Northern Ireland: are older patients missing out?

Background: Influenza is a common respiratory disease that may affect a large proportion of the population annually. Vaccination is recommended for those most at risk of complications; namely everyone aged 65 and over and those under 65 who are immunosuppressed or who have chronic disease.
Objective: To explore the variations in influenza vaccination rates for the winter of 2000, with special reference to uptake amongst older patients.
Design: An audit of vaccination rates amongst 12 practices that participate in the Northern Ireland Data Retrieval in Primary Care Project.
Methods: Data were extracted from the practice computers; Read codes were used to determine if the patient was immunosuppressed or suffered from chronic heart, lung or renal disease or had diabetes mellitus. The postcode of residence was used as a proxy for residence in a nursing or residential home as this could not be determined directly from the data. Multiple regression analysis was used to determine which factors were significantly related to vaccination uptake.
Results: We vaccinated 10,427 patients in these practices against influenza with a vaccination rate of 65.2% for the over-65 population. Uptake rates peaked at age 85 and declined thereafter so that only half of those aged over 90 had been vaccinated. This age related decline in vaccination rates was evident in ten of the twelve practices. The presence of chronic disease increased the likelihood of vaccination even amongst older patients. Logistic regression confirmed the decline in uptake rates at older ages and suggested that patients who shared the address of a nursing or residential home were less likely to have been vaccinated.
Conclusions: We feel that the current monitoring of influenza vaccination rates needs to be extended so that uptake amongst those most at risk, namely the very oldest and those in nursing and residential homes, can be adequately assessed.