Could DAAs Stop an Epidemic of Hepatitis C among HIV-Positive Men?

The rate of transmission of hepatitis C virus (HCV) among HIV-positive men who have sex with men (MSM) could be substantially reduced by the scaled up use of direct-acting antiviral (DAA) treatments along with behavioral interventions, according to a recent study conducted in the United Kingdom.

The study, published in the Oxford Journal of Clinical Infectious Diseases recently, was conducted by Natasha K. Martin, DPhil, of the University of California San Diego, and colleagues.

An epidemic of HCV among HIV-positive MSM “has been documented in cities in Europe, Australia, and the United States, but with little evidence of transmission among HIV-uninfected MSM,” say the authors.

Because London is considered a hub of this epidemic, and because detailed data is available, this study was conducted there. The authors developed a dynamic model to assess the trajectory of the epidemic and to “project the impact of scaled-up HCV treatment as prevention,” they said.

The researchers used data from an on-going observational study called the UK Collaborative HIV Cohort (UK CHIC), which collects data from 16 HIV treatment centers, as well as additional data on HCV from 11 treatment centers. They describe the model as being “a dynamic, deterministic model of HCV transmission, progression, and treatment among diagnosed HIV-positive MSM.”

Analyzing the collected data showed that “the cumulative HCV prevalence among HIV-positive MSM increased from 7.25% in 2004 to 9.86% in 2011,” the researchers report. Those rates of increase match the estimated percentage (7%) of HIV-positive MSM who report using methamphetamine or injectable drugs. The researchers say, “These high-risk individuals contribute more than one-third of prevalent and incident infections in 2015.”

The model shows that if things continue as they are, the epidemic will continue to expand, and if DAAs are provided at the current rates, chronic prevalence will remain flat. However, if DAAs are administered to 60% 80%, or 100% of recently diagnosed individuals, the result would be a respective decrease of 33%, 44%, or 55% by 2025.

Although there are limitations to this study, including many unknown factors and variables, the results show substantial reductions are possible. The researchers conclude, “Given their importance in driving ongoing HCV transmission, there is a need to develop effective interventions to address high-risk behaviors associated with injecting and other drug use among MSM.”