Epidemiological impact and cost‐effectiveness of providing long‐acting pre‐exposure prophylaxis to injectable contraceptive users for HIV prevention in South Africa: a modelling study

INTRODUCTION: Although pre‐exposure prophylaxis (PrEP.) is an efficacious HIV prevention strategy, its preventive benefit has not been shown among young women in sub‐Saharan Africa, likely due to non‐adherence. Adherence may be improved with the use of injectable long‐acting PrEP methods currently being developed. We hypothesize that providing long‐acting PrEP to women using injectable contraceptives, the most frequently used contraceptive method in South Africa, could improve adherence to PrEP, result in a reduction of new HIV infections, and be a relatively easy‐to‐reach target population. In this modelling study, we assessed the epidemiological impact and cost‐effectiveness of providing long‐acting PrEP to injectable contraceptive users in Limpopo, South Africa. METHODS: We developed a deterministic mathematical model calibrated to the HIV epidemic in Limpopo. Long‐acting PrEP was provided to 50% of HIV negative injectable contraceptive users in 2018 and scaled‐up over two years. We estimated the number of HIV infections that could be averted by 2030 and the drug price of long‐acting PrEP for which this intervention would be cost‐effective over a time horizon of 40 years, from a healthcare payer perspective. In the base‐case scenario we assumed long‐acting PrEP is 75% effective in preventing HIV infections and 85% of infected individuals are on antiretroviral drug therapy (ART) by 2030. In sensitivity analyses we adjusted PrEP effectiveness and ART coverage. Costs between $519 and $1119 per disability‐adjusted life‐year (DALY) averted were considered potentially cost‐effective, and <$519 as cost‐effective. RESULTS: Without long‐acting injectable PrEP, 224,000 (interquartile range 176,000 to 271,000) new infections will occur by 2030; use of long‐acting injectable PrEP could prevent 21,000 (17,000 to 26,000) or 9.8% (8.9% to 10.6%) new HIV infections by 2030 (including 6000 (4000 to 7000) in men). Long‐acting PrEP would prevent 34,000 (29,000 to 39,000) or 12,000 (8000 to 15,000) at 75% and 95% ART coverage by 2030 respectively. To be considered potentially cost‐effective the annual long‐acting PrEP drug price should be <$16, and/or ART coverage remains at <85% in 2030. CONCLUSIONS: Providing long‐acting PrEP to injectable contraceptive users in Limpopo is only potentially cost‐effective when long‐acting PrEP drug prices are low. If low prices are not feasible, providing long‐acting PrEP only to women at high risk of HIV infection will become important.