A cost-effectiveness analysis of 21-valent and 20-valent pneumococcal conjugate vaccines in adults aged 65 years in Italy

Background: The European Medicines Agency approved the 20-valent pneumococcal conjugate vaccine (PCV20) in 2022. Several cost-effectiveness analyses (CEAs) conducted across Europe have indicated that the broader serotype coverage of PCV20 (compared to PCV13 or PCV15) offers better health outcomes (higher quality-adjusted life years, QALYs) while reducing total healthcare costs in adults. The availability of a new 21-valent pneumococcal conjugate vaccine (PCV21), approved for use in adults, makes it appropriate to assess its cost-effectiveness in comparison with PCV20, given the differences in serotype coverage, as well as the different possible vaccination strategies that can be adopted (including different coverage scenarios). Methods: This was evaluated adopting the Italian National Health Service perspective, using a cost-utility Markov model. The expected health consequences and costs of vaccination with PCV21 were compared with the administration of PCV20, assuming a 75% coverage in the cohort aged 65 years (as for the Italian National Immunization Plan - NIP); lifetime horizon has been adopted. Results: A reduction in disease events was estimated with PCV21 vaccination: −18 (-0.2%) deaths; −23 (-3.4%) cases of bacteraemia (excluding meningitis); −5 (-3.8%) cases of meningitis; −156 (-0.2%) hospitalised NBP cases; and −316 (-0.2%) non-hospitalised NBP cases. Overall, in the Italian population, a total benefit gain of 132 life years and 111 QALYs would be achieved. On the cost side, an increase of EUR 7.8 million is estimated, due to an increase of EUR 8.4 million in vaccination costs, and a saving of EUR 0.7 million in other direct health costs. The comparison between PCV21 and PCV20 resulted in an Incremental Cost-Effectiveness Ratio (ICER) of EUR 70,175 per QALY gained, suggesting that PCV21 is unlikely to be considered cost-effective at a willingness-to-pay threshold of €30,000 per QALY gained. Discussion: The sensitivity and scenario analyses identify the key drivers of the results. In particular, epidemiological variability and differences in serotype distribution suggest that the choice among alternative vaccination strategies should also be interpreted in light of the local epidemiological context. We conclude that, considering future increase in vaccination coverage among eligible adults, the use of PCV20 in the general population remains an option useful in terms of economic sustainability, as it provides significant savings with only a limited impact in terms of health consequences.