While a large scale-up of hepatitis C virus treatment among current and former injection drug users (IDUs) would reduce HCV prevalence, a truly massive scale-up would be required to actually drive down the rate of new infections among the population. Researchers conducted a model of hep C transmission in a theoretical community of current and former IDUs based on data from studies of the Baltimore hep C population.

The researchers considered various strategies: treating only the IDUs not actively using and doing so about 15 years after they were infected; and a more aggressive approach of treating all IDUs regardless of whether they were using, doing so one to five years after these individuals were infected, and following this method with or without scaling up harm reduction interventions.

The model suggested that widespread hep C treatment could reduce hep C prevalence by 40 percent among the current and former IDU population over a 20-year period. If less than 88 percent of the IDU population received treatment, almost all of the reduction in the number of people living with the virus would be the direct result of curing people, as opposed to the indirect result of cures preventing further transmission of the virus. The model showed that for treatment up to this level of coverage, the drop in hep C prevalence varied little by who was treated—active users, those remaining abstinent, or all IDUs—or how long after they were infected that they received treatment.

To actually impact hep C transmission over a two-decade period, treatment needed to scale up to cover more than 90 percent of the IDU population, treating individuals one to two years after infection and scaling up harm reduction interventions. But even with such increased efforts, each course of treatment would only avert 0.8 new cases of hep C.

“Given the vast amount of treatment needed to impact transmission,” the researchers concluded, “programs should prioritize clinical considerations and the relative impact of harm reduction.”

To read the conference abstract, click here.