Vaccination versus treatment of influenza in working adults: A cost-effectiveness analysis

Purpose To determine the cost-effectiveness of influenza vaccination, antiviral therapy, or no intervention for healthy working adults, accounting for annual variation in vaccine efficacy. Methods We conducted a cost-effectiveness analysis based on published clinical trials of influenza vaccine and antiviral drugs, incorporating 10 years of surveillance data from the World Health Organization. We modeled influenza vaccination, treatment of influenza-like illness with antiviral drugs, or both, as compared with no intervention, targeting healthy working adults under age 50 years in the general community or workplace. Outcomes included costs, illness days, and quality-adjusted days gained. Results In the base case analysis, the majority of costs incurred for all strategies were related to lost productivity from influenza illness. The least expensive strategy varied from year to year. For the 10-year period, antiviral therapy without vaccination was associated with the lowest overall costs ($234 per person per year). Annual vaccination cost was $239 per person, and was associated with 0.0409 quality-adjusted days saved, for a marginal cost-effectiveness ratio of $113 per quality-adjusted day gained or $41,000 per quality-adjusted life-year saved compared with antiviral therapy. No intervention was the most expensive and least effective option. In sensitivity analyses, lower vaccination costs, higher annual probabilities of influenza, and higher numbers of workdays lost to influenza made vaccination more cost-effective than treatment. If vaccination cost was less than $16 or time lost from work exceeded 2.4 days per episode of influenza, then vaccination was cost saving compared with all other strategies. Conclusion Influenza vaccination for healthy working adults is reasonable economically, and under certain circumstances is cost saving. Antiviral therapy is consistently cost saving.