A curative regimen would decrease HIV prevalence but not HIV incidence unless targeted to an ART-naïve population

Abstract

HIV curative strategies currently under development aim to eradicate latent provirus, or prevent viral replication, progression to AIDS, and transmission. The impact of implementing curative programs on HIV epidemics has not been considered. We developed a mathematical model of heterosexual HIV transmission to evaluate the independent and synergistic impact of ART, HIV prevention interventions and cure on HIV prevalence and incidence. The basic reproduction number was calculated to study the potential for the epidemic to be eliminated. We explored scenarios with and without the assumption that patients enrolled into HIV cure programs need to be on antiretroviral treatment (ART). In our simulations, curative regimes had limited impact on HIV incidence if only ART patients were eligible for cure. Cure implementation had a significant impact on HIV incidence if ART-untreated patients were enrolled directly into cure programs. Concurrent HIV prevention programs moderately decreased the percent of ART treated or cured patients needed to achieve elimination. We project that widespread implementation of HIV cure would decrease HIV prevalence under all scenarios but would only lower rate of new infections if ART-untreated patients were targeted. Current efforts to identify untreated HIV patients will gain even further relevance upon availability of an HIV cure.

Figure 1. ART and HIV prevention coverage drive decreases in epidemic potential if only ART treated patients are eligible for cure interventions.

(A) Values of the basic reproduction number (R₀) assuming different annual treatment and cure rates assuming that enhanced HIV prevention is not available (k = 0). (B) Effects of HIV prevention coverage (k) on HIV eradication (curves represent R₀ = 1). Under all scenarios, increasing annual cure rate has a negligible impact on R₀.

Figure 2. ART coverage is the most critical factor driving decreased HIV incidence if cure is available to only ART treated patients.

Dynamics of HIV incidence measured as number of new HIV infections cases per 100 person years over 20 years for different combinations of HIV prevention coverage (k), ART initiation (τ) and cure (δ). Prevention programs are most effective at low treatment initiation rates per year.

Figure 3. ART coverage and annual cure rate drive decreases in HIV prevalence if cure is available to only ART treated patients.

Dynamics of HIV prevalence measured as percentage HIV infected in the population over 20 years for different combinations of HIV prevention coverage (k), ART initiation (τ) and cure (δ).

Figure 4. ART coverage, annual cure rate and HIV prevention coverage drive decreases in epidemic potential if ART untreated patients are recruited directly into cure programs.

(A) Values of the basic reproduction number (R₀) assuming different annual treatment and cure rates assuming that enhanced HIV prevention is not available (k = 0). (B) Effects of HIV prevention coverage (k) on HIV eradication (curves represent R₀ = 1).

Figure 5. ART and cure coverage drive decreased HIV incidence if ART untreated patients are recruited directly into cure programs.

Dynamics of HIV incidence measured as number of new HIV infections cases per 100 person years over 20 years for different combinations of HIV prevention coverage (k), ART initiation (τ) and cure (δ).

Figure 6. ART and cure coverage drive decreased HIV prevalence if ART untreated patients are recruited directly into cure programs.

Dynamics of HIV prevalence measured as percentage HIV infected in the population over 20 years for different combinations of HIV prevention coverage (k), ART initiation (τ) and cure (δ).