The potential impact of dengue vaccination with, and without, pre-vaccination screening.

BACKGROUND

The World Health Organization defined a 'screen and vaccinate' strategy as its recommended policy for the licensed dengue vaccine (Dengvaxia, Sanofi Pasteur), so that only individuals with previous dengue infection are vaccinated. The objectives of the present study were to build upon a recently published analysis of the benefits and risks associated with dengue vaccination to evaluate the public health impact and cost-effectiveness of a screen and vaccinate strategy.

METHODS

The current analysis was based on a previously reported transmission model and added, for the screening part, three rapid diagnostic tests with identical specificity (99%) but alternative sensitivities (50-70-90%) in the detection of prior dengue infection. The impact of a screen-and-vaccinate strategy considered nine settings representing different levels of transmission intensity. Outcomes (dengue-related hospitalizations, severe dengue, and symptomatic dengue) were assessed according to the level of transmission setting. The cost-effectiveness of vaccination in 10 endemic countries was also assessed.

RESULTS

Although associated, in most cases, with a lower population impact than a 'no-screening' approach, a screen and vaccinate strategy is more effective in reducing the number of hospitalized and severe cases prevented per vaccination performed and generates positive health benefits for individuals screened and subsequently vaccinated. As a result, this intervention is cost-effective in all countries considered except for very low transmission settings. The overall population impact of a screen and vaccinate approach is also likely to be improved by the use of several rounds of screening (up to 48% reduction in dengue hospitalization over 10 years with 5 rounds).

CONCLUSIONS

WHO recommended option of a screen and vaccinate policy is likely to have a positive impact both at the individual and population level across a wide range of transmission settings and has the potential to be as, if not more, cost-effective than a no screening strategy.