Objectives: To compare sex risk for HIV and other sexually transmitted infections (STIs) among young heroin injecting drug users (YHIDUs) and non-injecting heroin users, including former injectors (YNIHU_F) and never injectors (YNIHU_N).

Methods: YHIDUs (n=335), YNIHU_F (n=71) and YNIHU_N (n=164), aged 18-30 were non-treatment recruited in New York City, 3/1996-3/2003, serotested, and administered structured interviews about their past-30-day sexual risk behaviors and sex partner (SP) networks.  Adjusted odds ratios (AOR) are estimated controlling for age, gender, race/ethnicity, and years since initiating heroin use.  Statistical significance is p<0.05*.

Results: The mean age was 23.9 years (SD=3.7); 67% were male and 67% white.  The mean years since initiating heroin use was 5.7 (SD=3.7).  Of those serotested, 3% of YHIDUs, 2% of YNIHU_F, and 7% of YNIHU_N were seropositive for HIV (ns); and, respectively, 22%, 23%, and 17% for hepatitis B virus (ns).  Comparisons are:

	Unprotected sex	Multiple SP	Current IDU SP*	Ever IDU SP*	Men-who-have-sex-with-men SP	HIV/hepatitis infected SP*
YNIHU_N (ref)	52%	24%	7%	17%	7%	4%
YNIHU_F	39%	23%	21%, AOR=4.0	31%, AOR=2.4	8%	10%
YHIDUs	44%	15%	40%, AOR=9.9	45%, AOR=3.9	4%	26%, AOR=3.8

Conclusions: Among young heroin users, active and former IDUs do not significantly differ from never injectors in engaging in unprotected sex and having multiple sex partners.  However, active heroin injectors' sex networks had the greatest probability of being or becoming infected.  Preventing injecting among non-injecting heroin users will reduce both their injecting and sexual risk of infection with HIV and infection with other STIs.