Increased Methamphetamine Use among Persons Who Inject Drugs in Hai Phong, Vietnam, and the Association with Injection and Sexual Risk Behaviors.

Methamphetamine use has increased significantly in Southeast Asia in the last 5-10 years, but there is little research on risk behaviors associated with the increase in this region. We evaluate injection and sexual risk behaviors associated with current methamphetamine use among heterosexual persons who inject drugs (PWID) in Hai Phong, Vietnam. We recruited 1336 PWID and assessed associations between methamphetamine use, injection and sexual risk behaviors, stratified by HIV serostatus. There were several statistically significant associations between methamphetamine use and sexual risk behaviors among HIV-positive PWID, but we did not find any associations between methamphetamine use and injection risk behaviors. Methamphetamine may increase the likelihood of PWID transmitting HIV to non-injecting primary sexual partners, as it can reduce ART adherence and can lead to weakening of the immune system and increased HIV viral loads. All participants were injecting heroin, and methamphetamine use may interfere with opiate use treatment. Public health efforts should focus on the large increase in methamphetamine use and the associated sexual risk behaviors. Emphasis on sexual risk behavior, particularly among those who are HIV-positive, in conjunction with continued monitoring of ART adherence and HIV viral loads, is critical.