Implementation and Analysis of Respondent Driven Sampling: Lessons Learned from the Field

Those who engage in illegal or stigmatized behaviors, which put them at risk of HIV infection, are largely concentrated in urban centers. Owing to their illegal and/ or stigmatized behaviors, they are difficult to reach with public health surveillance and prevention programs. 1 These populations include illicit drug users, sex workers and men who have sex with men. Development and implementation of adequate prevention services targeting hidden populations requires data on risk behaviors and disease prevalence from non-biased samples. In the last two decades, a number of sampling methods have been used to collect risk behavior and disease prevalence data from highly at-risk populations and to direct survey participants to prevention services. These include venue-based time–space sampling, targeted sampling, and snowball sampling. Time–space (also called time–location or venue–day–time) and targeted sampling provide coverage limited to population members who are readily accessible; those who are missed may differ from those who are Bcaptured[. 2 Targeted sampling fares well when compared to other forms of convenienc

Diversity among clients of female sex workers in India: comparing risk profiles and intervention impact by site of solicitation. implications for the vulnerability of less visible female sex workers.

BACKGROUND: It seems generally accepted that targeted interventions in India have been successful in raising condom use between female sex workers (FSWs) and their clients. Data from clients of FSWs have been under-utilised to analyse the risk environments and vulnerability of both partners. METHODS: The 2009 Integrated Biological and Behavioural Assessment survey sampled clients of FSWs at hotspots in Andhra Pradesh, Maharashtra and Tamil Nadu (n=5040). The risk profile of clients in terms of sexual networking and condom use are compared across usual pick-up place. We used propensity score matching (PSM) to estimate the average treatment effect on treated (ATT) of intervention messages on clients' consistent condom use with FSW. RESULTS: Clients of the more hidden sex workers who solicit from home or via phone or agents had more extensive sexual networks, reporting casual female partners as well as anal intercourse with male partners and FSW. Clients of brothel-based sex workers, who were the least educated, reported the fewest number/categories of partners, least anal sex, and lowest condom use (41%). Consistent condom use varied widely by state: 65% in Andhra Pradesh, 36% in Maharashtra and 29% in Tamil Nadu. Exposure to intervention messages on sexually transmitted infections was lowest among men frequenting brothels (58%), and highest among men soliciting less visible sex workers (70%). Exposure had significant impact on consistent condom use, including among clients of home-based sex workers (ATT 21%; p=0.001) and among men soliciting other more hidden FSW (ATT 17%; p=0.001). In Tamil Nadu no impact could be demonstrated. CONCLUSION: Commercial sex happens between two partners and both need to be, and can be, reached by intervention messages. Commercial sex is still largely unprotected and as the sex industry gets more diffuse a greater focus on reaching clients of sex workers seems important given their extensive sexual networks