Cost-effectiveness of vaccination against pneumococcal bacteremia among elderly people.

CONTEXT

Clinical, epidemiologic, and policy considerations support updating the cost-effectiveness of pneumococcal vaccination for elderly people and targeting the evaluation only to prevention of pneumococcal bacteremia.

OBJECTIVE

To assess the implications for medical costs and health effects of vaccination against pneumococcal bacteremia in elderly people.

DESIGN

Cost-effectiveness analysis of pneumococcal vaccination compared with no vaccination, from a societal perspective.

SETTING AND PARTICIPANTS

The elderly population aged 65 years and older in the United States in 3 geographic areas: metropolitan Atlanta, Ga; Franklin County, Ohio; and Monroe County, New York.

MAIN OUTCOME MEASURES

Incremental medical costs and health effects, expressed in quality-adjusted life-years per person vaccinated.

RESULTS

Vaccination was cost saving, ie, it both reduced medical expenses and improved health, for all age groups and geographic areas analyzed in the base case. For people aged 65 years and older, vaccination saved $8.27 and gained 1.21 quality-adjusted days of life per person vaccinated. Vaccination of the 23 million elderly people unvaccinated in 1993 would have gained about 78000 years of healthy life and saved $194 million. In univariate sensitivity analysis, the results remained cost saving except for doubling vaccination costs, including future medical costs of survivors, and lowering vaccination effectiveness. With assumptions most unfavorable to vaccination, cost per quality-adjusted life-year ranged from $35 822 for ages 65 to 74 years to $598 487 for ages 85 years and older. In probabilistic sensitivity analysis, probability intervals were more narrow, with less than 5% probability that the ratio for ages 85 years and older would exceed $100000.

CONCLUSIONS

Pneumococcal vaccination saves costs in the prevention of bacteremia alone and is greatly underused among the elderly population, on both health and economic grounds. These results support recent recommendations of the Advisory Committee on Immunization Practices and public and private efforts under way to improve vaccination rates.