The combined effects of expanded HIV treatment access and harm reduction methods, including needle exchange and opioid substitution therapy (OST), such as methadone, have prevented thousands of new cases of the virus among injection drugs users (IDUs) in British Columbia, Canada.
Publishing their findings in The Lancet HIV, researchers studied health administrative and registry data on B.C.’s population of people diagnosed with HIV to create a mathematical model simulating the effects of interventions on rates of HIV transmission through injection drug use between 1996 and 2013.
For their calculations, the researchers presumed, likely quite conservatively, that prescribing antiretrovirals reduced by 50 percent the overall risk that a group of IDUs on antiretroviral (ARV) therapy would transmit the virus through needle sharing.
The study authors estimated that the expansion of harm reduction services and ARV treatment to IDUs averted 3,204 new cases of the virus during the study period. In a hypothetical scenario in which HIV treatment had no effect on transmission risk, they estimated that harm reduction services alone accounted for 77 percent of the averted new cases of the virus. In a separate hypothetical scenario in which harm reduction services were never escalated past 1996 levels, they estimated that ARV treatment alone would have been responsible for preventing 44 percent of the averted cases of the virus.
The researchers acknowledged that if the power of ARVs to prevent HIV transmission through needle sharing is as great as its power to prevent transmission through sex, HIV treatment expansion could be responsible for preventing more of the averted new cases of the virus than expanded harm reduction. “Nonetheless,” they write, “harm reduction services had a vital role in reducing HIV incidence in British Columbia and should be viewed as essential and cost-effective tools in combination implementation strategies to reduce the public health and economic burden of HIV/AIDS.”
To read the study abstract, click here.
To read a press release about the study, click here.