HIV and hepatitis C monitoring must increase among drug users, study finds

Countries must intensify efforts to track HIV and hepatitis C virus (HCV) incidence among people who inject drugs, and prioritise this group in prevention and elimination work, according to new University of Bristol-led research.

UNAIDS and the World Health Organisation have recommended targets for ending the HIV/AIDS epidemic and eliminating HCV as a public health threat by 2030. To validate these targets, countries must measure HIV and HCV incidence and document a decline over time. People who inject drugs are one of the key risk groups for HIV and HCV infection, so it is important for countries to track HIV and HCV incidence in this high-risk group.

Bristol Medical School researchers sought to address this by summarising global HIV and primary HCV incidence data among people who inject drugs together with age- and sex- or gender-specific incidence data. They conducted a systematic review and meta-analysis by searching for relevant studies published between 2000 and 2022.

Data on HIV and HCV incidence in people who inject drugs was limited. Globally, only 14% and 12% of countries have at least one estimate on these measures, respectively. In many cases, estimates are not recent, not nationally representative, and were usually limited to one city.

The availability of estimates was also geographically skewed, with few estimates from middle-income countries for HCV, and only one HIV and HCV incidence estimate from low-income countries.

Although limited, available data suggest that HIV and HCV incidence are high in this population – on average 1.7 per 100 person per year for HIV and 12.1 per 100 person per year for HCV. These figures mean that, on average, if 100 people who inject drugs uninfected with HIV and HCV were followed for one year, nearly two would acquire HIV and 12 would acquire HCV.

However, there is considerable variability in these estimates: the ranges are 0.1-31.8 per 100 person per year for HIV and 0.2-72.5 per 100 person per year for HCV.

Additionally, young people who inject drugs were found to have on average a 1.5-times greater risk of HIV and HCV than older people who inject drugs, and women had a 1.4-times greater risk of HIV and a 1.2-times greater risk of HCV than men.

The findings suggest there is a pressing need for most countries to scale-up measurement and monitoring of HIV and HCV incidence among people who inject drugs, and to prioritise this population in prevention and elimination efforts.

In addition, given that young people who inject drugs and women who inject drugs have higher risk of getting infected with both HIV and HCV, age-appropriate and gender-appropriate prevention measures are urgently needed to reach and engage with these vulnerable risk subgroups.

Dr Adelina Artenie, Senior Research Associate at Bristol Medical School and corresponding author of the paper, said: ‘It can be challenging and expensive to measure HIV and HCV incidence, which is probably why so few estimates are available.

‘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. This means that people who inject drugs could be overlooked when prevention and treatment strategies are put in place to eliminate HIV and HCV in a country.

‘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 prioritise them for prevention and care.’

Image: National Cancer Institute