Impact and cost-effectiveness of frequent HIV re-testing among key populations in Viet Nam: a modeling study

ABSTRACT Background HIV testing and counseling is a key component of HIV prevention and the entry point into the treatment cascade, which improves for individual clinical outcomes and reduces onward HIV transmission. Current guidelines recommend at least annual testing for key populations. More frequent testing could provide health benefits, but these additional services increase the program the cost-effectiveness is not well-evaluated. Methods We used a compartmental mathematical model to simulate the health and economic impact of HIV testing one to four times per year for men who have sex with men, people who inject drugs, and female sex workers in Viet Nam. Model outcomes included costs, HIV infections, HIV-related deaths, and disability-adjusted life years (DALYs) associated with each scenario. We used an opportunity cost-based cost-effectiveness threshold of US $2,255 per DALY averted, discounted costs and health benefits at 3% annually, and used a time horizon from 2021 to 2030 to calculate incremental cost-effectiveness ratios (ICERs). Results Compared to the baseline scenario, more frequent HIV testing was estimated to incrementally avert 10.2%, 5.2%, 3.0%, and 1.6% discounted infections for one-, two-, three-, and four-tests per year, respectively. ICERs associated with each scenario ranged from $464, $1,190, $1,762, and $2,727 per DALY averted for one-, two-, three-, and four-tests per year, respectively. Conclusions Increased HIV testing frequency for key populations was projected to avert HIV incidence, mortality, and disability in Viet Nam and was cost-effective. Settings with a similar context should consider strategies on how to optimize retesting among key populations.