Many populations worldwide have seen a decrease in HIV prevalence, but in several countries drug use is fueling new HIV epidemics. Prevention has become a key focus of the 16th International AIDS Conference in Toronto, highlighting the importance of targeting and engaging drug users in the fight against HIV and AIDS.

Users of illegal injection drugs are at a disproportionally higher risk of becoming infected with HIV, and their health is poorer when they are HIV-positive. But non-injection drugs are also of concern in the fight against HIV and AIDS.

“Meth is the major driver of the HIV epidemic in the United States,” said Dr. Steffanie Strathdee of the University of California, San Diego at a conference presentation on Monday.

Dr. Strathdee’s research focused on heterosexual methamphetamine (or meth) users, but there has been concern about meth use in the gay community possibly leading to risky sexual behavior.

“One of the recreational purposes of the use of meth is increased sexual stimulation,” said Amy Drake of the Centers for Disease Control and Prevention on Tuesday. Therefore, Drake said, “Meth use among men who have sex with men is of concern for HIV prevention.”

The CDC surveyed homosexuals, bisexuals and other men who have sex with men (MSMs) in 15 American cities about their sexual activities and drug use. They found that meth use was more common in men infected with HIV. Also, regardless of HIV status, MSM meth users were more likely to report engaging in high-risk unprotected anal sex. “It is clear from our data and other data that meth use among men who have sex with men presents a challenge,” Drake said.

But drug users are often left out of the fight against HIV/AIDS because of discrimination against illegal drugs and those who use them. During the conference’s opening ceremony on Sunday, Bill and Melinda Gates called attention to the stigma that prevents drug users from gaining access to testing, treatment and prevention supplies like condoms and clean needles.

As well, misconceptions can contribute to the stigma, even among the users themselves. There’s a widespread impression that using meth causes irrational and risky behavior, said Sandra L. Bullock of the University of Waterloo in Waterloo, Ontario.

“It can lead to a self-fulfilling prophecy,” Bullock said during a presentation on Tuesday. “If we’re telling people that using this is going to cause you to do things you’re not going to otherwise do, it can be a built-in excuse.”

Facilities like safe injection sites are key to preventing HIV infection in drug users and controlling the epidemic, said Dr. Alex Wodak, former president of the International Harm Reduction Association, at a conference session on Tuesday.

Harm reduction is effective, safe and cost-effective, and it’s necessary to push for its use even if it appears to some to be promoting illegal drug use, said Dr. Wodak, now director of the Alcohol and Drug Service at St. Vincent’s hospital in Australia.

Behavioral intervention can reduce risk behavior even if it doesn’t target drug use directly, said Dr. Strathdee. “Heterosexual active meth users can reduce their high risk sexual behavior even though they’re still engaging in active meth use.”

In the face of “monstrous” stigma, there is a need for a comprehensive, whole-person approach that engages drug users where they are at the time of intervention, not where we wish they were, said Walter Cavalieri, director of The Canadian Harm Reduction Network.

“Harm reduction is not just needle exchanges, not just safe injection facilities,” said Cavalieri. “Needle exchange has done wonderful work, but more than anything it’s a bridge to more work.”

Day-to-day support and physical and mental health also need to be considered, he said, along with a wider look at the effectiveness of current restrictions on illegal drugs and drug paraphernalia and how they affect use and stigma. “You cannot look at harm reduction without looking at how we deal with regulation of drugs.”