Hepatitis C virus (HCV) transmission rates among injection drug users (IDUs) vary widely between Western cities, with differences likely significantly driven by local harm-reduction efforts. Specifically, access to syringe services programs (SSPs) likely helps contain hep C transmission among local IDU populations.  

Publishing their findings in Clinical Infectious Diseases, researchers studied population-based cohort data from HCV-negative IDUs in Boston, Baltimore, San Francisco, Montreal, Amsterdam, Sydney and Melbourne covering 1985 to 2011.

Out of 1,391 initially HCV-negative IDUs who were followed for a cumulative 1,645 years, 371 contracted hep C during follow-up, for an infection rate of 22.6 percent per year of follow-up.

The hep C infection rate was the highest—and remained high throughout the study period—in Baltimore (32.6 percent infection rate per year of follow-up), San Francisco (24.7 percent) and Montreal (23.5 percent). The rate was lowest in Melbourne (7.5 percent) and Amsterdam (13.1 percent) and was moderate in Sydney (21.4 percent).

In the cities with the highest infection rates, higher rates of syringe and injection-drug equipment sharing and a lower use of opioid agonist therapy (such as methadone) were linked with hep C infection.

The overall HCV infection rate in all cities during the study period was 21.5 percent per year of follow-up. The overall infection rate fell an average of 18 percent every three years, from a high of 31.3 percent during 1994 to 1997.

This decline in the overall infection rate was driven down by the dropping rates of the Australian cities and of Amsterdam, whose rate fell most significantly. According to the study authors, the improvements seen in these cities’ infection rates likely reflect “an early and sustained implementation of harm reduction services. The Netherlands and Australia were global leaders in scaling up harm reduction programs to include [SSP] services.”

A recent Centers for Disease Control and Prevention (CDC) report found that American IDUs are increasingly using SSPs. However, the CDC has also found that the hep C infection rate in the United States has risen sharply in recent years.

For a POZ feature article on the future of SSPs in the current political era, click here.

To read the study, click here.