Systematic literature review of cost-effectiveness analyses of adult 15- and 20-valent pneumococcal vaccines.

Background: The economic and public health benefits of adult pneumococcal vaccines vary across countries due to different epidemiology and costs. We systematically reviewed and summarized findings and assumptions of cost-effectiveness analyses (CEA) of the recently introduced 15- and 20-valent pneumococcal conjugate vaccines (PCV15 and PCV20) in adults.

Methods: We performed a systematic search for CEA studies of PCV15 and/or PCV20 versus existing strategies via PubMed, EMBASE, CEA Registry, EconLit, HTA Database, and NITAG resource center through April 23, 2024. Study characteristics, methods, assumptions, and findings were extracted independently by two reviewers; quality was assessed using ECOBIAS. Results were synthesized qualitatively to summarize key attributes and conclusions.

Results: Of 137 identified records, 26 studies were included; the majority (24/26) concerned high-income countries. All employed static Markov-type models comparing higher-valent PCVs used alone or in combination with 23-valent pneumococcal polysaccharide vaccine (PPSV23) to current recommendations (PPSV23 alone, PCV13 alone, PCV13 + PPSV23, no vaccination). Most studies (22/26) concluded PCV20 used alone was cost-saving (dominant) or cost-effective compared to other adult pneumococcal strategies (PPSV23 alone, PCV13 ± PPSV23, PCV15 ± PPSV23, or no vaccination). PCVs were generally assumed to have serotype-specific effectiveness equal to PCV13 efficacy in the pivotal trial, though four studies used estimates from a Delphi panel; protection was assumed to last between 10 and 20 years. PPSV23 was assumed to have lower effectiveness against non-bacteremic pneumonia and shorter duration of protection. Herd effects from higher-valent PCVs in childhood (12/26), serotype replacement (2/26), or both (1/26) were included in half (13/26) of studies, which attenuated adult vaccine impact. Most studies were assessed as low risk of bias; five abstracts did not provide sufficient information for assessment.

Conclusion: Current evidence indicates that 20-valent PCV used alone is likely to be cost-effective or dominate other adult pneumococcal strategies. Future research is needed to address remaining uncertainties in assumptions and to support evidence-based policymaking.