Assessing HIV risk in hard-to-reach populations

Background
This paper presents the first mixed methods study of the HIV risk environments of MSW in China. Chinese MSW are highly stigmatised, occupying marginal social positions, undertaking illegal/hidden behaviours. They are at an increased risk of HIV infection due to multiple risk exposures.
Methods
The mixed methods research was conducted in Guangdong, China in 2011. Following ethnographic mapping, MSW (n=251) were surveyed using a structured questionnaire and a sub-sample (n=21) were interviewed in-depth.
Results
Levels of HIV knowledge varied according to a number of socio-economic variables. Reasons for entering sex work, and subsequent risk taking behaviours including drug use appeared to largely centre around economic needs or desires. The survey reveals that levels of condom use varied considerably by partner type and gender. Qualitative analyses suggest that issues of intimacy and stigma played an important role in this behavioural decision making process. These men also show very high levels of mobility, making them hard to reach.
Discussion
As a mixed methods study of MSW in China, we present a more nuanced exploration of the drivers of HIV in this marginalised group than previous work has been able to. We present evidence that may be useful in identifying potential avenues for more targeted interventions.

Context-specific typologies of female sex workers (FSWs) are essential for the design of HIV intervention programming. This study develops a novel FSW typology for the analysis of transactional sex risk in rural and urban settings in Indonesia. Mixed methods include a survey of rural and urban FSWs (n=310), in-depth interviews (n=11), key informant interviews (n=5) and ethnographic assessments. Thematic analysis categorises FSWs into 5 distinct groups based on geographical location of their sex work settings, place of solicitation, and whether sex work is their primary occupation. Multiple regression analysis shows that the likelihood of consistent condom use was higher among urban venue-based FSWs for whom sex work is not the only source of income than for any of the other rural and urban FSW groups. This effect was explained by the significantly lower likelihood of consistent condom use by rural venue-based FSWs (adjusted OR: 0.35 95% CI 0.13-0.92, p=0.033). The FSW typology and differences in organisational features and social dynamics are more closely related to the risk of unprotected transactional sex, than levels of condom awareness and availability. Interventions need context-specific strategies to reach the different FSWs identified by this study’s typology.

We evaluate Respondent Driven Sampling (RDS)’s claim of population representation with empirical data by exploring the network coverage in a RDS study of female sex workers (FSW) in China. We take advantage of unique information on the social networks of FSW obtained from two overlapping studies of FSWs --RDS and a venue-based sampling approach (PLACE) -- and use an exponential random graph modeling (ERGM) framework from local networks to construct the likely network from which our observed RDS is drawn. We then run recruitment chains over this simulated population and produce a sample with characteristics consistent with the observed RDS. We estimate population coverage rates by comparing population proportions and RDS sample proportions. We discuss the results in light of (a) potential estimation improvements implicit in network information, (b) strategies for improving coverage rates, and (c) multiple sources of potential variability in coverage.