| A Stochastic Monte Carlo simulation model using epidemiological and economic data from several data sources was developed to examine the net return to influenza vaccination measured in terms of net present value (NPV), benefit/cost ratio (B/C ratio) and incremental cost-effectiveness ratio (C/E ratio). The model was used to rank national priorities using different criteria and provides a tool to support national, state, and local health care decision-making in preparation for a probable influenza pandemic.; Burden of illness as well as cost-benefit and cost-effectiveness analyses were performed in parallel to the decision-analytic model which captured the different phases of an influenza pandemic. Ranking analysis was also conducted to determine the groups of individuals that influenza vaccination should be promoted to using different criteria for setting priorities. Additionally, a number of sensitivity and scenario analyses were conducted to evaluate the robustness of the model.; The findings revealed that in the absence of a large-scale vaccination intervention, the estimates of the total economic impact in the US of influenza pandemic ranged from {dollar}40 billion based on baseline estimates to approximately {dollar}70 billion for attack rates twice as much as the ones used in baseline analysis. At any given attack rate, loss of life due to influenza-related complications accounted for approximately 83 percent of all economic losses. The net value of vaccinating against influenza pandemic varied substantially by age, gross attack rate, assumed distribution of cases among age groups, vaccine effectiveness, compliance, and cost of vaccination. At a cost of {dollar}34 per vaccine, the mean net value of vaccination was always positive, regardless of the value of other variables, with the exception of vaccinating non-high risk individuals who are 5–9 years of age. Regardless of the criteria used for evaluation, the society should focus on vaccinating individuals who are 65 years or older. The variables that cause the largest percentage changes in net returns were found to be the death rate, the cost per vaccine, and gross attack rates. |
