Global Study Finds Data on HIV, HCV in PWID Elusive but Essential

The first global meta-analysis of direct surveys of HIV/AIDS and HCV incidence in people who inject drugs (PWID) contributes data that could be key to developing effective public health interventions, according to investigators in the HIV and HCV Incidence Review Collaborative Group

These data, often sparse and reflecting substantial heterogeneity across regions, are intended to inform policies and actions to meet UNAIDS and WHO goals of ending the HIV/AIDS epidemic and eliminating HCV as a public health threat by 2030.

"Given how incomplete the data on HIV and HCV incidence are among people who inject drugs, the true scale of these epidemics globally remains unknown. If there are no data to understand the scale of transmission in a country, we cannot expect timely action to reduce it," study lead author Adelina Artenie, PhD, Population Health Sciences, Bristol Medical School and National Institute for Health and Care Research, Health Protection Research Unit in Behavioural Science and Evaluation, University of Bristol, Bristol, UK remarked in comments to the press.

"We hope that our systematic review draws attention to the importance of monitoring the HIV and HCV epidemics among people who inject drugs and to the need to prioritize them for prevention and care," Artenie said.

Prior to their meta-analysis of estimates drawn from direct surveys, the only global estimate of HIV and HCV incidence among PWID that Artenie and colleagues found in their review was a modeling study, which had estimated HCV incidence of 8.6 per 100 person-years.

The investigators now report findings from 64 estimates of HIV incidence (30 from high-income countries and 34 from low- or middle-income countries) and 66 estimates of HCV (52 from high- and 14 from low-income countries). The studies of HIV were conducted between 1987-2011, and between 1992-2021 for HCV.

Artenie and colleagues report a pooled HIV incidence of 1.7 per 100 person-years (95% CI 1.3-2.3); and pooled HCV incidence of 12.1 per 100 person-years (10.0-14.6). Notably, they found that young PWID had a greater risk of HIV than older PWID (RR 1.5, 95% CI 1.2-1.8); and women had a greater risk of HIV than men (RR 1.4 [1.1-1.6]). They emphasize the importance of public health interventions reaching these at-risk populations.

"To be able to reach elimination, we need to improve interventions for this vulnerable group, and collect data to show that we (are) achieving progress. Both of these things need to be improved," study principal investigator Peter Vickerman, DPhil, University of Bristol, commented.

The investigators found more than twice the incidence of HIV in low-income countries than high-income countries, which they attributed to greater availability of treatment in the latter. Although the data did not reflect HCV incidence varying between geographical regions, they suspect this is a function of incomplete data, as treatment of HCV had also increased, particularly in high-income countries.

Artenie and colleagues acknowledge that scarce and heterogeneous evidence make it difficult to determine geographical and temporal differences in HIV and HCV incidence, and call for additional measures and monitoring.

"Estimates of HIV and HCV incidence with time among PWID are important for monitoring the trajectory of epidemics, adapting the public health response and assessing progress towards achieving the UNAIDS and WHO 2030 targets," Artenie and colleagues declared.