A dynamic model, accounting for herd immunity, was used to facilitate the synthesis of the cost and clinical data. The time horizon was 80 years and the authors stated that the two study perspectives were the third party payer and societal.
The effectiveness data were derived from published studies, with data specific to Canada being used where possible. Birth rates, death rates and population per age group were obtained from vital statistics data for Canada. The main clinical parameters were the rates of infection and transmission, vaccine efficacy, and mortality.
Monetary benefit and utility valuations:
Quality of life estimates were derived from published studies, but the instruments used to derive these utilities were not reported.
Measure of benefit:
The primary measure of benefit was the number of quality-adjusted life-years (QALYs) gained, which were discounted at an annual rate of 5%.
The costs from the third party payer perspective (direct costs) included physician visits, hospitalisation, death, liver transplantation, and public health costs. From the societal perspective, they included these direct costs, plus time costs (e.g. the cost of work loss) and costs borne by the patients and the private sector. The resource use and cost data were identified from a systematic review of the literature, supplemented by expert opinion where required. The price year was 2005 and all costs were reported in Canadian dollars (CAD) and were discounted at an annual rate of 5%.
Analysis of uncertainty:
Both univariate and probabilistic sensitivity analyses were performed, with some of the results of the probabilistic sensitivity analysis being displayed in the form of a cost-effectiveness acceptability curve.