# Serostatus Testing & Dengue Vaccine Cost-Benefit Thresholds

## TL;DR

This study shows that pre-vaccination serostatus testing for dengue can be cost-effective and improve health outcomes, especially when testing costs are low, by optimizing vaccination strategies based on age-specific seroprevalence.

## Contribution

The paper introduces a general approach to determine cost thresholds and optimal ages for test-then-vaccinate dengue strategies using simple models and real-world data.

## Key findings

- Test-then-vaccinate strategies are more beneficial at younger ages.
- Multiple years of testing can be more advantageous than a single test.
- Cost-effective testing can enhance the economic viability of dengue vaccination programs.

## Abstract

The World Health Organisation currently recommends pre-screening for past infection prior to administration of the only licensed dengue vaccine, CYD-TDV. Using a bounding analysis, we show that despite additional testing costs, this approach can improve the economic viability of CYD-TDV: effective testing reduces unnecessary vaccination costs while increasing the health benefit for vaccine recipients. When testing is cheap enough, those trends outweigh additional screening costs and make test-then-vaccinate strategies net-beneficial in many settings. We derived these results using a general approach for determining price thresholds for testing and vaccination, as well as indicating optimal start and end ages of routine test-then-vaccinate programs. This approach only requires age-specific seroprevalence and a cost estimate for second infections. We demonstrate this approach across settings commonly used to evaluate CYD-TDV economics, and highlight implications of our simple model for more detailed studies. We found trends showing test-then-vaccinate strategies are generally more beneficial starting at younger ages, and that in some settings multiple years of testing can be more beneficial than only testing once, despite increased investment in testing.