High-level overview of model subsystems.

Following decades of progress, recent years have seen a resurgence of cholera. This has led to unprecedented demand for vaccines from the global emergency stockpile of oral cholera vaccines (OCVs), for outbreak and humanitarian use. As a consequence of chronic supply shortages, preventive vaccination has been suspended since 2022. Although strategic demand scenarios have been published for OCV, models that integrate OCV supply and demand across long time horizons are lacking. Therefore, a quantitative system dynamics model is presented to simulate OCV market dynamics between 2013–2035. The model considers the evolving OCV supply landscape as well as the impact of preventive efforts. Building on stakeholder-driven scenario design, simulations help identify leverage points to improve OCV market health and assess the individual and combined effect of interventions on accelerating cholera control. Specifically, country adoption of preventive vaccination programs and complementary investments in water and sanitation infrastructure are critical to reduce the risk of cholera. Although more resource-intensive, re-vaccination of at-risk populations helps sustain outbreak prevention. It also offers potential benefits such as increasing long-term demand predictability and the overall market size. These serve as important incentives to maintain supplier diversity, thus improving market health. However, since many cholera endemic countries rely on donor support to access OCV, budget constraints associated with reduced development aid can jeopardize programmatic ambitions. Interventions such as the use of rapid diagnostic tests and price competition of procurement can help meet country needs. Finally, market dynamics are influenced by the policies around when to resume preventive OCV use in endemic countries and 2-dose reactive vaccination. Specifically, inventory policies based on the current available stock level versus incoming stock in transit are compared. Aligning OCV supply with demand, both in time and quantity, will be critical to address immediate needs and support broader multi-sectoral activities towards cholera elimination.