DISEASE IMPACT AND COST-EFFECTIVENESS OF A NEW DENGUE VACCINE TAK003 IN THAILAND

Abstract

Intro: Dengue, a vector-borne disease, is a global threat to public health with incidence increased from 0.5 to 5.2 million cases between 2010 and 2019. Data collected over ∼57 months of the phase-3 DEN-301 trial of the candidate vaccine (TAK-003) demonstrated long-term efficacy against symptomatic and hospitalized dengue. The objective of the present study was to assess the disease impact and cost-effectiveness of vaccination with two doses of TAK-003 in Thailand. Methods: A deterministic compartmental dynamic model of dengue transmission was developed to explicitly model host and vector populations, seasonality, and up to four serotype-specific infections. It was fitted to the dengue incidence observed in Thailand accounting for under-reporting. The disease impact and cost-effectiveness of vaccination were assessed over a 20- year time horizon. Vaccination strategies included routine vaccination of 11-year- olds, and routine with catch-up campaigns of 5, 10 or 20 age cohorts, respectively. Vaccine efficacy was derived and extrapolated from the TAK-003 phase-3 pivotal efficacy DEN-301 trial. Findings: Routine vaccination at age 11 with TAK-003 prevented 41% of symptomatic cases and 50% of hospitalized cases in Thailand, which translated to 138,783 DALYs averted. Routine with catch-up campaigns of 5, 10 and 20 age- cohorts resulted in a reduction of symptomatic cases by 46%, 49% and 55%, respectively, and hospitalized cases by 57%, 62% and 69%, respectively. All vaccination strategies were cost-saving compared to no vaccination and could lead to cost-savings of US$1.9 million - $1.6 billion (across a price range of 25$-60$/dose) over 20 years from the societal perspective where both medical costs and patients’ out-of-pocket costs and productivity loss were considered. Conclusion: Routine vaccination with TAK-003 could lead to significant reductions of symptomatic and hospitalized dengue along with considerable societal and healthcare cost-savings in Thailand. The impact could be even larger when catch-up campaigns of broader age cohorts were considered.