Modelling the impact of HIV and HCV prevention and treatment interventions for people who inject drugs in Dar es Salaam, Tanzania

People Who Inject Drugs in Mozambique: We need to normalize HIV treatment and care services in specialized community centers for people who inject drugs!

Globally, People Who Inject Drugs (PWID) have limited healthcare, treatment, and prevention services, and they frequently experience stigma and negative attitudes toward healthcare providers when accessing services. Mozambique, with a general population HIV prevalence of 12.5%, has one of the highest rates in the world, and the PWID population has the highest HIV prevalence among key populations, estimated at nearly 50%. Less than half of HIV positives who inject drugs are linked to HIV treatment and are retained in care. One of the main reasons is that HIV treatment is mainly provided in a public health facility and PWID delayed accessing healthcare since they anticipated mistreatment from multiple levels of healthcare providers. To improve the health outcomes in this group, we need to treat them where they feel comfortable and respected. In this commentary, we outline the importance of innovative approaches to enhance the management of HIV-positive PWID. As a country gets close to controlling the HIV epidemic, refocusing and targeting responses to the highest-risk groups becomes even more essential for shaping more effective HIV interventions and achieving epidemic control.

Comparison of Empirically Derived and Model-Based Estimates of Key Population HIV Incidence and the Distribution of New Infections by Population Group in Sub-Saharan Africa

BACKGROUND

The distribution of new HIV infections among key populations, including female sex workers (FSWs), gay men and other men who have sex with men (MSM), and people who inject drugs (PWID) are essential information to guide an HIV response, but data are limited in sub-Saharan Africa (SSA). We analyzed empirically derived and mathematical model-based estimates of HIV incidence among key populations and compared with the Joint United Nations Programme on HIV/AIDS (UNAIDS) estimates.

METHODS

We estimated HIV incidence among FSW and MSM in SSA by combining meta-analyses of empirical key population HIV incidence relative to the total population incidence with key population size estimates (KPSE) and HIV prevalence. Dynamic HIV transmission model estimates of HIV incidence and percentage of new infections among key populations were extracted from 94 country applications of 9 mathematical models. We compared these with UNAIDS-reported distribution of new infections, implied key population HIV incidence and incidence-to-prevalence ratios.

RESULTS

Across SSA, empirical FSW HIV incidence was 8.6-fold (95% confidence interval: 5.7 to 12.9) higher than total population female 15-39 year incidence, and MSM HIV incidence was 41.8-fold (95% confidence interval: 21.9 to 79.6) male 15-29 year incidence. Combined with KPSE, these implied 12% of new HIV infections in 2021 were among FSW and MSM (5% and 7% respectively). In sensitivity analysis varying KPSE proportions within 95% uncertainty range, the proportion of new infections among FSW and MSM was between 9% and 19%. Insufficient data were available to estimate PWID incidence rate ratios. Across 94 models, median proportion of new infections among FSW, MSM, and PWID was 6.4% (interquartile range 3.2%-11.7%), both much lower than the 25% reported by UNAIDS.

CONCLUSION

Empirically derived and model-based estimates of HIV incidence confirm dramatically higher HIV risk among key populations in SSA. Estimated proportions of new infections among key populations in 2021 were sensitive to population size assumptions and were substantially lower than estimates reported by UNAIDS.

Modeling the Impacts of Prevention and Treatment Interventions on Hepatitis C Among People Who Inject Drugs in China

INTRODUCTION

Injection drug use is the main transmission route of hepatitis C virus (HCV) in China. The prevalence of HCV remains high at 40-50% among people who inject drugs (PWID). We developed a mathematical model to predict the impacts of different HCV intervention strategies on the HCV burden in Chinese PWID by 2030.

METHODS

We developed a dynamic deterministic mathematical model to simulate the transmission of HCV among PWID in China between 2016 and 2030, using domestic data based on the real cascade of HCV care. We considered various intervention scenarios, including treatment regimens, harm reduction program (HRP) coverage, enhanced testing and referral for treatment.

RESULTS

HCV incidence will exhibit a gradual but slow declining trend from 12,970 in 2016 to 11,761 in 2030 based on current screening and treatment practices among PWID (scenario 1). Scaled-up HCV screening and treatment integrated with HRPs (scenario 8) demonstrated the most substantial reduction in HCV burden, being the only intervention scenario that could achieve the World Health Organization's (WHO's) HCV elimination target. Specifically, the HCV incidence in 2030 is projected to be reduced by 81.42%, and HCV-related deaths are projected to be reduced by 91.94%.

CONCLUSION

Our study indicates that achieving WHO elimination targets is an extremely challenging goal that requires substantial improvements in HCV testing and treatment among PWID (scenario S8). The findings suggest that coordinated improvements in testing, treatment, and harm reduction programs could greatly reduce the HCV burden among PWID in China, and urgent policy changes are needed to integrate HCV testing and treatment into existing HRPs.

Modelling the impact of HIV and hepatitis C virus prevention and treatment interventions among people who inject drugs in Kenya

OBJECTIVES

People who inject drugs (PWID) in Kenya have high HIV (range across settings: 14-26%) and hepatitis C virus (HCV; 11-36%) prevalence. We evaluated the impact of existing and scaled-up interventions on HIV and HCV incidence among PWID in Kenya.

DESIGN

HIV and HCV transmission model among PWID, calibrated to Nairobi and Kenya's Coastal region.

METHODS

For each setting, we projected the impact (percent of HIV/HCV infections averted in 2020) of existing coverages of antiretroviral therapy (ART; 63-79%), opioid agonist therapy (OAT; 8-13%) and needle and syringe programmes (NSP; 45-61%). We then projected the impact (reduction in HIV/HCV incidence over 2021-2030), of scaling-up harm reduction [Full harm reduction ('Full HR'): 50% OAT, 75% NSP] and/or HIV (UNAIDS 90-90-90) and HCV treatment (1000 PWID over 2021-2025) and reducing sexual risk (by 25/50/75%). We estimated HCV treatment levels needed to reduce HCV incidence by 90% by 2030.

RESULTS

In 2020, OAT and NSP averted 46.0-50.8% (range of medians) of HIV infections and 50.0-66.1% of HCV infections, mostly because of NSP. ART only averted 12.9-39.8% of HIV infections because of suboptimal viral suppression (28-48%). Full HR and ART could reduce HIV incidence by 51.5-64% and HCV incidence by 84.6-86.6% by 2030. Also halving sexual risk could reduce HIV incidence by 68.0-74.1%. Alongside full HR, treating 2244 PWID over 2021-2025 could reduce HCV incidence by 90% by 2030.

CONCLUSION

Existing interventions are having substantial impact on HIV and HCV transmission in Kenya. However, to eliminate HIV and HCV, further scale-up is needed with reductions in sexual risk and HCV treatment.

Awareness and willingness to use HIV oral pre-exposure prophylaxis among people who inject drugs in Dar es Salaam, Tanzania: A cross-sectional survey

People who inject drugs (PWID) are at increased risk of HIV infection. Pre-exposure prophylaxis (PrEP) could help in HIV prevention among PWIDs. However, little is known about PrEP use among PWIDs in low and middle-income countries. This study reports the awareness of and willingness to use PrEP and the associated factors among PWID in Tanzania. A cross-sectional survey was conducted using respondent-driven sampling (RDS) to recruit PWIDs in Dar es Salaam, Tanzania. Data were collected using an interviewer-administered questionnaire. Chi-square statistical test was used during data analysis. The P-value of < 0.05 was used to ascertain the statistically significant relationship. IBM SPSS Statistics 25.0 was used to analyze the data. The analysis consisted of 260 PWIDs. The mean age of the respondents was 39.0 years with a standard deviation (SD) of ±7.5. Most of the respondents were male (n = 232, 89.2%) with primary education (n = 176, 67.7%). Despite the low awareness of PrEP (n = 42, 165.28%) in the study sample, the majority (n = 239, 91.9%) were willing to use PrEP. Both awareness of and willingness to use PrEP were associated with gender (p = .002 and p = < .001), awareness of HIV prevention programs(p = < .001 and p = .006), selling sex (p = .010 and p = .021), and frequency of condomless sexual intercourse (p = .029 and p = .025) respectively. In multivariable logistic regression, only gender(p = 0.046) was related to awareness of PrEP while awareness of HIV prevention programs (p = 0.009), the risk level of HIV infection(p = < .001), number of sexual partners(p = 0.046), and frequency of condomless sex(p = 0.032) were associated with willingness to use PrEP. Other factors were not statistically significant. Despite low awareness, PWIDs are highly willing to use PrEP. Future research should assess the acceptability of injectable PrEP for PWID, as their acquaintance with injection may make the formulation more practical.