The incremental cost-effectiveness ratio of vaccination over no vaccination and treatment was ECU 11,778 for adults. Vaccination in the elderly led to lower costs and number of life years lost. For adults, the most sensitive variables include the incidence and mortality rate of pneumococcal pneumonia. For the elderly, the most sensitive variables included the incidence rate and the probability of hospitalisation. For adults, the incremental cost-effectiveness ratio led to a net savings in the best case and was ECU 568,833 in the worst case. For the elderly, the incremental cost-effectiveness ratio led to a net savings in the best case and was ECU 51,592 in the worst case.