Is immunising all patients with chronic lung disease in the community against influenza cost effective? Evidence from a general practice based clinical prospective cohort study in Utrecht, The Netherlands

Abstract

Study objective: There is little information on the potential benefit of immunising all patients with chronic lung disease in the community against influenza. The clinical effectiveness and economic benefit was established of the influenza vaccination programme in a general practice based cohort of adult patients with chronic lung disease followed up during the 1995/96 influenza A epidemic.

Design: A prospective cohort study from October 1995 to March 1996.

Setting: The study was undertaken in the Utrecht General Practices Network with six large group practices, covering a total population of approximately 50,000 patients in the Netherlands.

Patients: Computerised medical records of 1696 patients with chronic lung disease aged over 18 years with an indication for vaccination according to the Dutch GP guidelines were reviewed.

Main results: The overall attack rate of any complication, including all cause death, low respiratory tract infection, and acute cardiac disease was 15%. Exacerbations of lung disease were most frequent (13%). Death, pneumonia, and acute cardiac disease were mainly limited to patients > or = 65 years. No effectiveness of the immunisation programme could be established in patients 18-64 years (n = 1066), after controlling for baseline prognosis in multivariable logistic regression analysis. In vaccinees > or = 65 years (n = 630), the occurrence of any complication was reduced by 50% (95% CI 17, 70%). The economic benefit was estimated at 50 Pounds per elderly vaccinee.

Conclusions: This study suggests that in the Netherlands immunisation of elderly patients with chronic lung disease against influenza is effective and cost-saving, hence these patients should be given high priority. More, preferably experimental, studies are needed to establish whether adult lung patients under 65 years in the community will also benefit from vaccination.