Budget impact of pneumococcal vaccination in adults and elderly in Italy

Abstract

Background Streptococcus pneumoniae or pneumococcus, is responsible for severe invasive infections (IPD) in high risk groups and in the elderly. Moreover the pneumococcus is the most common cause of community acquired pneumonia (CAP) in adults. Two pneumococcal vaccines are currently available for adult population: 23-valent polysaccharide (PPV23) and 13-valent conjugate (PCV13). The aim of this study is the budget impact analysis of pneumococcal vaccination in adult and elderly populations in Italy from the perspective of the National Health System (NHS) at 1, 3 and 5 years of follow-up. Methods A Markov model was developed based on the cohort of the Italian population to describe pneumococcal disease in elderly (>65 years) and high risk adult (50-64 years) populations in correlation with their immunization status. Three vaccination strategy scenarios were considered; PPV23 alone, PCV13 alone or a combination of the two vaccines. The model considers costs of vaccination and other direct medical costs related to pneumococcal disease (non-bacteraemic pneumococcal pneumonia and pneumococcal meningitis). In the base case no difference in effectiveness of the two vaccines was considered. The NHS perspective and a simulated follow-up of 1, 3 and 5 years were adopted. A one-way and probabilistic sensitivity analysis was performed in order to evaluate the robustness of results. Results In the base case, considering the cohort of population vaccinated in 2012 and followed for 5 years, the model estimated a total direct cost of €96.3, €106.7 and €117.1 million for the Scenario 1 (PPV23 alone), Scenario 2 (50% PPV23 and 50% PCV13) and Scenario 3 (PCV13 alone), respectively. At 5 year follow-up, the incremental costs of using PCV13 alone in a static model are positive: €102 million in comparison with the use of PPV23 alone. One-way and probabilistic sensitivity analyses show that budget impact results are the most sensitive to vaccines costs. Conclusions In this study the same effectiveness was considered for both vaccines, a low (5%) vaccine coverage was applied and the serotype replacement effect was not evaluated. Given these conditions, from the NHS perspective, PPV23 alone is the preferred strategy.