The 23-valent pneumococcal polysaccharide vaccine. Part II. A cost-effectiveness analysis for invasive disease in the elderly in England and Wales.

The 23-valent pneumococcal polysaccharide vaccine (PPV) has been available for a number of years and is recommended for high-risk categories. Relatively immunocompetent elderly people are not included in this group, although their probability of getting invasive pneumococcal infection is high. The objective of this study was to assess whether vaccinating all elderly people over 65 years of age was a cost-effective policy for England and Wales. The analysis was performed comparing the cost and health effects produced by vaccination, to what would have been occurred if vaccination were not introduced. A decision analysis model was used in order to predict health outcomes under different vaccination scenarios. Unit costs were applied to the outcome and the cost per life-year gained was calculated. Sensitivity analysis was performed to allow for uncertain parameters to vary. The current UK recommendation does not appear to be the most cost-effective strategy due to the low level of efficacy of the vaccine in high-risk groups (HRG) and their shorter life expectancy. Routine vaccination of all elderly appears to be more cost-effective. These results are, nevertheless, very much dependent on the uncertainties around vaccine efficacy estimates, which appear to be still present, especially in HRG, and on the number of hospitalisations and deaths attributable to invasive pneumococcal disease (IPD).