Cost-effectiveness analysis of influenza and pneumococcal vaccinations among elderly people in Japan

During the periods of seasonal flu in 2003 and 2004, it was found that about 45 percent of elderly people in Japan had been inoculated with influenza vaccines. Comparatively, however, the proportion of inoculation with pneumococcal vaccine was only 0.1 percent. Taking into account such incongruent proportions, this study assesses health and economic benefits of vaccination strategies for both influenza and pneumonia particularly for the elderly population in Japan. To accomplish this objective, a cost-effectiveness analysis was conducted with the use of the Monte Carlo simulation based on the data from medical literature as well as from the public organizations, wherein three strategic patterns were delineated and compared (i) no vaccination (ii) influenza vaccine only, and (iii) combined influenza with pneumococcal vaccines. The cost for one year of life saved by each strategy was compared with the scenario of no vaccinations. It was found that for 100,000 elderly people over 65 years of age in Japan, the cost-effectiveness ratio of influenza-only vaccination was 516,332 Japanese yen per one year of life saved, while the combined vaccinations of influenza with pneumococcal was 459,874 Japanese yen for the same benefit. The incremental cost-effectiveness ratio of the strategies (iii) versus (ii) was 426,698 Japanese yen per one year of life saved for 100,000 people. Consequently it was indicated that the combined vaccinations would be more cost-effective than the vaccination for influenza only.