Estimating clinical and economic impacts and cost-effectiveness of introducing 20-valent pneumococcal conjugate vaccine in Taiwan's pediatric National Immunization Program and impacts of a delayed implementation.

Following 13-valent pneumococcal conjugate vaccine (PCV13) introduction in Taiwan, pneumococcal disease incidence declined; however, incidences driven by non-PCV13 serotypes highlight the need for broader serotype coverage. In response to recent approval of 20-valent PCV (PCV20) for Taiwanese children, this study evaluated 1) health and economic impact of PCV20 in Taiwan's pediatric National Immunization Program (NIP) vs. standard of care (PCV13) and 15-valent PCV (PCV15) from both payer and societal perspectives; and 2) short- and long-term consequences of delayed implementation. A population-based, multiple-cohort Markov model based on Taiwan-specific epidemiological inputs accounting for population changes was adapted to assess health and economic outcomes of PCV20 vs. PCV13 and PCV15 over 10 y. Both direct effects in vaccinated cohort and indirect effects in the broader population were incorporated to capture full impact of switching PCV13 to PCV20 in Taiwan's pediatric NIP. Over the long-term, PCV20 2+1 would avert 162,435 pneumococcal disease cases and 4,340 deaths vs PCV13 2+1, while generating $2.3 billion in cost savings, indicating dominance. Similar results were observed vs. PCV15. Despite higher estimated costs than the 2+1 schedule, PCV20 (3+1) remained cost-effective vs. both comparators (2+1). Delaying PCV20 introduction resulted in substantial losses, with a 1-y delay causing over 3,200 additional cases and exceeding NT$40 million in forgone savings, doubling with a 2-y delay. Implementing PCV20 in Taiwan's pediatric NIP is projected to improve health outcomes and reduce costs, while delays in implementation would lead to significantly avoidable losses compared with PCV13- or PCV15-based programs.