HIV incidence among people who inject drugs in the Middle East and North Africa: mathematical modelling analysis

Abstract

Introduction: Emerging HIV epidemics have been documented among people who inject drugs (PWID) in the Middle East and North Africa (MENA). This study estimates the HIV incidence among PWID due to sharing needles/syringes in MENA. It also delineates injecting drug use role as a driver of the epidemic in the population, and estimates impact of interventions.

Methods: A mathematical model of HIV transmission among PWID was applied in seven MENA countries with sufficient and recent epidemiological data and HIV prevalence ≥1% among PWID. Estimations of incident and/or prevalent infections among PWID, ex-PWID and sexual partners of infected current and ex-PWID were conducted.

Results: The estimated HIV incidence rate for 2017 among PWID ranged between 0.7% per person-year (ppy) in Tunisia and 7.8% ppy in Pakistan, with Libya being an outlier (24.8% ppy). The estimated number of annual new infections was lowest in Tunisia (n = 79) and Morocco (n = 99), and highest in Iran and Pakistan (approximately n = 6700 each). In addition, 20 to 2208 and 5 to 837 new annual infections were estimated across the different countries among sexual partners of PWID and ex-PWID respectively. Since epidemic emergence, the number of total ever acquired incident infections across countries was 706 to 90,015 among PWID, 99 to 18,244 among sexual partners of PWID, and 16 to 4360 among sexual partners of ex-PWID. The estimated number of prevalent infections across countries was 341 to 23,279 among PWID, 119 to 16,540 among ex-PWID, 67 to 10,752 among sexual partners of PWID, and 12 to 2863 among sexual partners of ex-PWID. Increasing antiretroviral therapy (ART) coverage to the global target of 81% - factoring in ART adherence and current coverage - would avert about half of new infections among PWID and their sexual partners. Combining ART with harm reduction could avert over 90% and 70% of new infections among PWID and their sexual partners respectively.

Conclusions: There is considerable HIV incidence among PWID in MENA. Of all new infections ultimately due to injecting drug use, about 75% are among PWID and the rest among sexual partners. Of all prevalent infections ultimately attributed to injecting drug use as epidemic driver, about half are among PWID, 30% among ex-PWID and 20% among sexual partners of PWID and ex-PWID. These findings call for scale-up of services for PWID, including harm reduction as well as testing and treatment services.

Keywords: HIV; Middle East and North Africa; incidence; intervention; mathematical modelling; people who inject drugs; prevalence.

Figure 1

HIV transmission pathways in the population arising from injecting drug use. Panel (A) displays the various HIV transmission pathways that are due to injecting drug use, starting among people who inject drugs (PWID) and percolation of infection to the wider non‐injecting community – mainly sexual partners of current and ex‐PWID. The blue oval refers to the PWID population, while the white space around it refers to the general population. Black arrows refer to transmission chains. Panels (B) and (C) provide one example from Pakistan for the number of incident (B) and prevalent (C) infections that are caused by these transmission pathways and that affect the different members of the injecting and non‐injecting communities.

Figure 2

Effect of expanding antiretroviral therapy coverage (ART) on HIV incidence among people who inject drugs (PWID) and their heterosexual sex partners in the Middle East and North Africa (MENA). The graphs display, at various ART coverage levels, the number of new HIV infections and the number of infections averted in comparison with baseline (current year) estimations of HIV incidence among PWID and their heterosexual sex partners.

Figure 3

Effect of two comprehensive intervention packages on HIV incidence among people who inject drugs (PWID) (A) and their heterosexual sex partners (B) in all seven Middle East and North Africa (MENA) countries. The package with the less optimistic scenario includes reducing sharing by 25%, reducing the number of PWID by 10% and reducing injecting frequency by 10% (effect of opioid substitution therapy), increasing ART coverage to 50%, and increasing condom use by 25%. The package with the more optimistic scenario includes reducing sharing by 75%, reducing the number of PWID by 10% and reducing injecting frequency by 30%, increasing ART coverage to 81%, and increasing condom use by 75%. The graphs display the number of new HIV infections and the number of infections averted in comparison with baseline (current year) estimations of HIV incidence among PWID and their heterosexual sex partners.