Background:
In Pakistan MSWs and Hijras sell unprotected anal sex. Although this behavior clearly puts them at risk of HIV/STIs, little is known about their sexual behaviors and the prevalence of STIs/HIV among them.

Objective:
To determine the prevalence of STIs/HIV and compare the risk behaviors among MSWs and Hijras.

Method:
We conducted a cross sectional, community based study of 400 MSWs and 200 Hijras. Study subjects were administered a detailed interview questionnaire. Biological samples were collected for HIV, syphilis, gonorrhea and chlamydia.

Result:
The STI prevalence in MSWs was (HIV 4%, syphilis 23%, gonorrhea 36%, chlamydia 11%) and in Hijras (HIV 2%, syphilis 62%, gonorrhea 29%, chlamydia 18%). The median age was 24 years (range 12 – 43 years) with sexual debut at 14 years. Sexual practices differed with 25% MSWS vs 0.5% Hijras (p<0.05) reported buying or selling sex to women, 10% MSWs and 0% Hijras (p<0.001) had last sex act with a non-paying female partner, and condom use in last vaginal sex was 6% among MSWs. MSWs reported similar frequencies of receptive (38%) and insertive (44%) anal sex while Hijras engaged in mainly receptive anal sex (87%) (p=0.06). The overall condom use with male sex partners in last sex act was very low, 4% for MSWs and <1% for Hijras (p= 0.08).

Conclusion:
While both MSWs and Hijras engage in risky sexual practices, only MSWs practice bisexual behaviors that have wider implications for transmission of STIs/HIV to the general population.

Implications:
HIV prevention programs need to tailor different behavior change messages for the two subgroups that engage in MSM activities. Further research is needed to explore factors influencing bisexual behaviors among MSWs.