Men who have sex with both men and women (behaviorally bisexual men) may be at increased risk of HIV acquisition and transmission due to risky sexual behaviors. We recruited a sexual network comprised of behaviorally bisexual men and their sexual partners in Vientiane, Lao PDR in 2010 to inform our understanding of the potential for HIV transmission among heterosexual, homosexual, and bisexual networks. Participants completed a sexual behavior questionnaire and referred < 5 sexual partners. A total of 298 people were recruited, including 63 behaviorally bisexual men. Behaviorally bisexual men reported riskier sexual behaviors (number of sexual partners in the previous 12 months and consistent condom use) than behaviorally homosexual and heterosexual men. Using social network diagrammatic representation, heterosexual, homosexual, and bisexual networks are shown to be interlinked. This study demonstrates that behaviorally bisexual men are potential key drivers of HIV epidemics and require a targeted approach to sexual health promotion.Men who have sex with both men and women are an important population group for the control of HIV and other sexually transmitted infections (STIs) in Southeast Asia. Men who have sexual contact with both men and women may sexually link populations that are traditionally considered at high risk for HIV and STIs (such as homosexual or transgendered populations) and low risk populations (such as heterosexual women), and it is hypothesised that HIV and STIs may be transmitted during unprotected sexual contact. Men who have sex with both men and women

Men who have sex with men are a priority population for HIV control in Laos, but encompass men diverse in sexual orientation, gender identification, and behavior. Behaviorally bisexual men and their sexual partners were recruited in Vientiane, Laos, in 2010 using modified snowball sampling. Heterosexual-identifying bisexual men identified as exclusively/predominantly heterosexual and other bisexual men identified as bisexual or predominantly/exclusively homosexual. Sixty (68%) heterosexual-identifying and 38 (32%) other bisexual men were recruited; the median number of sex partners in the past year was eight and seven, respectively. Consistent condom use was low with regular (7%) and casual (35%) partners and did not differ by identity. More heterosexual-identifying (53%) than other bisexual (29%) men reported weekly alcohol consumption. Twelve (20%) heterosexual-identifying and 15 (54%) other bisexual men correctly answered all HIV-knowledge questions. High-risk behaviors for STI and HIV transmission were common. Targeted HIV prevention initiatives are needed, particularly to reach heterosexual-identifying bisexual men.

Young behaviourally bisexual men engaging in transactional sex may be at increased risk of HIV and STIs. Prevention interventions should consider the transient and informal nature of transactional sex in this population.

Behaviorally bisexual men (BBM) in Vientiane, Laos report high-risk sexual behaviors. We explore settings for meeting sex partners and associated risk behaviors among BBM in Laos. BBM and their sexual partners were recruited in Vientiane Capital using modified snowball sampling (2010). Settings for usually meeting sex partners and associations with risk behaviors were assessed. Among 88 BBM, the most common settings for men meeting male, kathoey, and female sex partners were private residences (48%, 37%, 51%, respectively) and hospitality settings (39%, 31%, 40%, respectively). Hospitality settings were more commonly reported by heterosexual-identifying BBM, and private residences more commonly reported by bisexual/homosexual-identifying BBM. Inconsistent condom use was high across partners and settings. Meeting partners in hospitality settings was associated with reporting a high number of female sex partners and frequently drinking alcohol before sex. Our results suggest that targeted health promotion initiatives in bars, clubs, and beer-shops could reach a high proportion of high-risk bisexual men, particularly heterosexual-identifying BBM.