Could prophylactic antivirals reduce dengue incidence in a high-prevalence endemic area?

Prophylactic drugs against dengue are currently under development. In this study, we explored how such prophylactic approaches might affect dengue cases in four communes of Nha Trang City, Vietnam. A community level dengue transmission survey indicated high levels of previous exposure to dengue (89.7%; 95% CI: 87.2,92.0). We fitted a spatially explicit model to an observed outbreak and simulated likely effectiveness of Case-Area Targeted Interventions (CATI) and One-Time Mass Distribution (OTMD) of drug and vector control strategies. Increasing the radius and effectiveness and decreasing delay of CATI was most effective, with drugs being more effective in averting dengue cases than vector control. Using an OTMD approach early in the outbreak required the least number of treatments to avert a case, suggesting that OTMD strategies should be considered as pre-emptive rather than reactive strategies. These findings show that pre-emptive interventions can substantially reduce the burden of dengue outbreaks in endemic settings. Author summary: Dengue is a mosquito-transmitted virus that is a leading cause of hospitalisation and death in Asian and Latin American countries. Protection against dengue infection mainly relies on mosquito control, but the current development of drugs against the virus opens new perspectives for prevention. To develop efficient prevention strategies, it is important to understand how prevalent and transmissible the virus is in a given population. In this study, we conducted a large serological survey in Nha Trang City, Vietnam, and developed a mathematical model to simulate the effect of preventive antiviral treatment on dengue outbreaks in that population. We compared the strength of these effects to that of other prevention startegies, such as mosquito control. We found that a large proportion of the population had been previously infected by dengue virus. In this context, our simulations showed that drugs are more effective in preventing dengue cases than mosquito control, and that these strategies are most effective when the radius of intervention increases and the delay of intervention decreases. These findings show that preventive administration of antivirals during outbreaks can substantially reduce the spread of dengue virus in part of the world where it is highly prevalent. [ABSTRACT FROM AUTHOR]