Population-level impact of an accelerated HIV response plan to reach the UNAIDS 90-90-90 target in Côte d'Ivoire: Insights from mathematical modeling

Abstract

Background: National responses will need to be markedly accelerated to achieve the ambitious target of the Joint United Nations Programme on HIV/AIDS (UNAIDS). This target aims for 90% of HIV-positive individuals to be aware of their status, for 90% of those aware to receive antiretroviral therapy (ART), and for 90% of those on treatment to have a suppressed viral load by 2020, with each individual target reaching 95% by 2030. We aimed to estimate the impact of various treatment-as-prevention scenarios in Côte d'Ivoire, one of the countries with the highest HIV incidence in West Africa, with unmet HIV prevention and treatment needs, and where key populations are important to the broader HIV epidemic.

Methods and findings: An age-stratified dynamic model was developed and calibrated to epidemiological and programmatic data using a Bayesian framework. The model represents sexual and vertical HIV transmission in the general population, female sex workers (FSW), and men who have sex with men (MSM). We estimated the impact of scaling up interventions to reach the UNAIDS targets, as well as the impact of 8 other scenarios, on HIV transmission in adults and children, compared to our baseline scenario that maintains 2015 rates of testing, ART initiation, ART discontinuation, treatment failure, and levels of condom use. In 2015, we estimated that 52% (95% credible intervals: 46%-58%) of HIV-positive individuals were aware of their status, 72% (57%-82%) of those aware were on ART, and 77% (74%-79%) of those on ART were virologically suppressed. Reaching the UNAIDS targets on time would avert 50% (42%-60%) of new HIV infections over 2015-2030 compared to 30% (25%-36%) if the 90-90-90 target is reached in 2025. Attaining the UNAIDS targets in FSW, their clients, and MSM (but not in the rest of the population) would avert a similar fraction of new infections (30%; 21%-39%). A 25-percentage-point drop in condom use from the 2015 levels among FSW and MSM would reduce the impact of reaching the UNAIDS targets, with 38% (26%-51%) of infections averted. The study's main limitation is that homogenous spatial coverage of interventions was assumed, and future lines of inquiry should examine how geographical prioritization could affect HIV transmission.

Conclusions: Maximizing the impact of the UNAIDS targets will require rapid scale-up of interventions, particularly testing, ART initiation, and limiting ART discontinuation. Reaching clients of FSW, as well as key populations, can efficiently reduce transmission. Sustaining the high condom-use levels among key populations should remain an important prevention pillar.

Fig 1. UNAIDS indicators under selected intervention scenarios among the population aged 15–59 years in Côte d’Ivoire (median with 95% credible intervals).

The UNAIDS indicators from left to right are (A) proportion of HIV-positive individuals aware of their status (data from [8,14], used for cross-validation), (B) proportion of those aware who are receiving antiretroviral therapy (ART) (the model was fitted to the proportion of HIV-positive individuals on ART), and (C) proportion of those on ART who are virally suppressed. The scenarios are as defined in Table 1. (SC1) Baseline: testing rate, ART recruitment rate, and ART failure rate stable at their 2015 values; (SC2) observed increase in those 3 rates from 2010–2015 projected through 2020; (SC3) UNAIDS: 90-90-90 objective reached in 2020 and 95-95-95 in 2030; (SC4) delayed UNAIDS: 90-90-90 objective reached in 2025 and maintained to 2030; and (SC5) UNAIDS 90-90-90 to 2030: 90-90-90 objective reached in 2020 and maintained to 2030. AIS, AIDS Indicator Survey; DHS, Demographic Health Survey; SC, scenario; UNAIDS, Joint United Nations Programme on HIV/AIDS.

Fig 2. Predicted median relative change in annual number of new HIV infections among 15–59-year-olds in Côte d’Ivoire from 2015 to 2030 under different intervention coverage scenarios.

The scenarios are detailed in Table 1. (SC1) Baseline: testing rate, antiretroviral therapy (ART) recruitment rate, and ART failure rate stable at their 2015 values; (SC2) current trends: observed increase in those 3 rates from 2010–2015 projected through 2020; (SC3) UNAIDS: 90-90-90 objective reached in 2020 and 95-95-95 in 2030; (SC4) delayed UNAIDS: 90-90-90 objective reached in 2025 and maintained to 2030; (SC5) UNAIDS 90-90-90 to 2030: 90-90-90 objective reached in 2020 and maintained to 2030, (SC6) UNAIDS in general population: 90-90-90 objective reached in 2020 and 95-95-95 in 2025 among the general population only; (SC7) UNAIDS in key populations (KP): 90-90-90 objective reached in 2020 and 95-95-95 in 2030 among FSW and MSM populations only; (SC8) UNAIDS in key populations and CFSW: 90-90-90 objective reached in 2020 and 95-95-95 in 2030 among MSM, FSW, and CFSW only; (SC9) UNAIDS plus condom use increases in key populations: 90-90-90 objective reached in 2020 and 95-95-95 in 2030 and a rise to 95% by 2020 of sexual acts protected by a condom among FSW and MSM; and (SC10) UNAIDS with condom drop in key populations: 90-90-90 objective reached in 2020 and 95-95-95 in 2030 and a decline by 25 percentage points of sexual acts protected by a condom among FSW and MSM. (95% credible intervals are not presented to ease visual interpretation.) CFSW, client(s) of female sex workers; FSW, female sex worker(s); Gen Pop, general population; MSM, men who have sex with men; SC, scenario; UNAIDS, Joint United Nations Programme on HIV/AIDS.

Fig 3. Cumulative fractions of all new HIV infections prevented (medians and 95% credible intervals) among 15–59-year-olds in Côte d’Ivoire between 2015 and 2030 for different intervention scenarios compared to baseline scenario 1 as the counterfactual.

(Details of the scenarios can be found in Table 1.) CFSW, client(s) of female sex workers; Gen Pop, general population; KP, key population(s); SC, scenario; UNAIDS, Joint United Nations Programme on HIV/AIDS.

Fig 4. Cumulative fractions of new HIV pediatric infections prevented (medians and 95% credible intervals) in Côte d’Ivoire between 2015 and 2030 for different intervention scenarios using the 2015 intervention coverage levels (scenario 1) as the counterfactual.

(Descriptions of the scenarios can be found in Table 1). SC, scenario; UNAIDS, Joint United Nations Programme on HIV/AIDS.