A new University of Minnesota School of Public Health study evaluating the costs and health benefits of supervised illicit-drug injection facilities in Toronto and Ottawa, Canada, predicts that such facilities would avert hundreds of HIV and hepatitis C infections over 20 years through reductions in the sharing of drug use equipment.

Researchers also determined that the optimal number of facilities for cost-effectiveness in each city is three in Toronto and two in Ottawa.

The study was published in the journal Addiction.

“These facilities, like all harm reduction approaches, are controversial because they are perceived as enabling drug use,” says Eva Enns, assistant professor and lead author of the study. “However, they are associated with many health and community benefits, including reduced sharing of drug use equipment, less injecting in public and drug-related litter, and lower rates of fatal overdoses.”

Currently, North America’s only supervised injection facility is in Vancouver, Canada, and researchers wanted to know if such facilities could benefit other communities with different demographic and geographic characteristics, in this case, Toronto and Ottawa.

Determining the optimal number of facilities was driven, in large part, by the geographic distribution of drug use in each city. In Ottawa, the study projected that two facilities would be used by 58 percent of people who inject drugs, but that additional facilities would yield only modest improvements in access.

Toronto, on the other hand, features greater geographic dispersion and each additional facility is estimated to provide considerable gains in coverage. A single facility was projected to be used by 11 percent of people who use drugs, which increased to 21 percent and 30 percent for two or three facilities respectively.

Enns and her colleagues find that their analysis indicates that supervised injection facilities are a good value, providing substantial health gains at reasonable costs. However, they believe it is up to communities in Ottawa and Toronto to decide how to proceed based on these findings.