Cost-effectiveness of 20-valent pneumococcal conjugate vaccine compared with 23-valent pneumococcal polysaccharide vaccine among adults in a Norwegian setting.

Background: The morbidity and mortality of adult diseases caused by S. pneumoniae increase with age and presence of underlying chronic diseases. Currently, two vaccine technologies against S. pneumoniae are used: the 23-valent pneumococcal polysaccharide vaccine (PPV23) and the pneumococcal conjugate vaccines, one of which is the 20-valent pneumococcal conjugate vaccine (PCV20) that has recently been approved for adults.

Objective: This study was conducted to investigate the cost-effectiveness of implementing PCV20 in a reimbursement scheme for Norwegian adults aged 18-99 years at risk of pneumococcal diseases and those aged 65 years and older at low risk compared to PPV23.

Methods: An established Markov model was adapted to a Norwegian setting to estimate the economic and clinical consequences of vaccinating the Norwegian population in specific age and risk groups against pneumococcal diseases. Inputs for the model were found in Norwegian or Danish real-world evidence or retrieved from available studies. The costs and clinical outcomes were assessed using a health sector perspective and a lifetime time horizon.

Results: The results showed that PCV20 was associated with better health outcomes including fewer disease cases, fewer disease-attributable fatalities, a higher gain of life years and quality-adjusted life years compared to PPV23. In addition, PCV20 had a lower total cost compared to PPV23. Therefore, PCV20 was the dominant vaccination strategy. The base case result was investigated in multiple sensitivity analyses, which showed that the results were robust to changes in input parameters and methodological assumptions, as PCV20 remained the dominant vaccination strategy in almost all scenarios.

Conclusion: Results showed that vaccinating the Norwegian adults with PCV20 was cost-effective compared to PPV23. Changes in the hospital cost of pneumonia, the price of PCV 20, the effectiveness of PCV20 against pneumonia, and the pneumonia disease incidence had the highest impact on the ICER, i.e., were the main drivers of the results.