Forecasting dengue vaccine demand in disease endemic and non-endemic countries.

BACKGROUND: A dengue vaccine in large-scale clinical trials could be licensed in several years. We estimated the potential vaccine demand for different introduction strategies in 54 dengue-endemic countries and for travelers from non-endemic countries to enable vaccine producers and public health agencies to better prepare for timely utilization of the vaccine.
RESULTS: Under our assumptions, 2.4-3.5 billion dengue vaccine doses would be needed in the first five years after introduction with >75% delivered in the public sector. Among 20 potential 'early-adopter' countries, an estimated 0.9-1.4 billion doses would be needed for the same introduction approach. For the private sector, covering 10% of children and 30% of adults an estimated 443-664 million doses would be required. In non-endemic countries, travelers could use an estimated 59-89 million vaccine doses, although the present product profile would make it unlikely to be able to administer vaccine in a timely manner.
METHODS: Calculations were based on 2015-2020 population projections for endemic countries in Asia and the Americas with populations >100,000. For dengue-endemic countries we assumed country-wide routine 12-23 month-old vaccination and catch-up vaccination among 2-14 year-old children employing a 2 or 3-dose schedule. Assumptions on expected vaccination coverage were based on country-specific public, private and travelers' sectors immunization performance.
CONCLUSIONS: Our results project an upper-limit estimate of vaccine demand, with actual demand depending on country priorities, cost and product profile. Given the potential for a dengue vaccine, policymakers in endemic and nonendemic countries should consider appropriate implementation strategies in advance of licensure.