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We sought to find a method that improves HIV estimates obtained through time-location sampling (TLS) used to recruit most-at-risk populations (MARPs). The calibration on residuals (CARES) method attributes weights to TLS sampled individuals depending on the percentile to which their logistic regression residues belong. Using a real country database, provided by EMIS-2010, with 9591 men who have sex with men (MSM) and an HIV prevalence of 12.1%, we simulated three populations (termed “pseudo-populations”) with different levels of HIV. From each pseudo-population, 1000 TLS samples were drawn, and the HIV prevalence estimated by the TLS method and by the CARES method were recorded and compared with the HIV prevalence of the 9591 men. Results showed that the CARES method improves estimates given by the TLS method by getting closer to the real HIV prevalence. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11524-019-00415-8) contains supplementary material, which is available to authorized users.

ObjectivesTo understand characteristics, perceptions, knowledge and behavior in the Qualitative Phase and to determine HIV/AIDS related knowledge, practices (including risk behaviors), HIV burden and its correlates in the quantitative phase among MSM population of Kolkata, West Bengal, IndiaMethodologyA mixed-method study with a qualitative phase followed by a quantitative cross-sectional component was conducted in Kolkata between August-2015 to June-2016. Focus group discussions and in-depth interview were conducted among 23 MSM. Time location sampling (TLS) with probability proportional to estimated attendance size was used to recruit MSM from 115 venues, corresponding to 3760 VDT complexes from which 584 subjects in randomly selected eligible VDT complexes were interviewed through an android based, tablet-PC assisted, pre-recorded questions-based, audio-integrated, color coded self-interview.ResultsMSM were uniformly treated with contempt in Indian society including by their parents. They were more likely to experience discrimination based on their sexual orientation compared to heterosexual counterpart. Most of them consciously did not disclose their orientation because of fear of rejection from families and society. Lack of support, protection and guidance from families and society influenced the overall well-being of this population. Almost all of them suffered from an impaired self-esteem and some degree of unhappiness because of widespread discrimination. The mechanism of coping varied and some were situational based on their anticipated emotional impact. In quantitative phase, the HIV burden was found to be 10.46%. 71% reported to have multiple male sex partners in their lifetime. 66% had multiple casual male sex partners. The significant predictors of HIV sero-positivity were higher age, acting as both as an anal insertive and receptive, irregular partners and unprotected sex.ConclusionsThe HIV burden among MSM was found to be substantially high in the current analysis. The significant predictors of HIV sero-positivity were higher age, acting as both as an anal insertive and receptive, irregular partners and unprotected sex. Majority of MSM in Kolkata were engaged in high risk activities that elevated their HIV risk. Targeted intervention for high-risk MSM seemed to be the need of the hour.

Adolescent girls and young women (AGYW) remain underserved and at risk for HIV acquisition in Ethiopia. However, there is significant risk heterogeneity among AGYW with limited consensus on optimal strategies of identifying vulnerable AGYW. This study assessed the utility of venue-based sampling approaches to identify AGYW at increased risk for HIV infection. Venue mapping and time-location-sampling (TLS) methods were used to recruit AGYW from three sub-cities of Addis Ababa, February–June 2018. Interviewer-administered surveys captured socio-demographic and behavioral characteristics. Measures of AGYW vulnerability were assessed geographically and described by venue type. A total of 2468 unique venues were identified, of which 802 (32%) were systematically selected for validation and 371 (46%) were eligible including many sites that would traditionally not be included as venues in need of HIV prevention services. Overall, 800 AGYW were enrolled across 81 sampled venues. AGYW reached were largely out-of-school (n = 599, 75%) with high proportions of AGYW reporting transactional sex (n = 101, 12.6%), food insecurity (n = 165, 20.7%) and migration (n = 565, 70.6%). Taken together, these data suggest the utility of TLS methods in reaching vulnerable, out-of-school AGYW in Addis Ababa, Ethiopia. Electronic supplementary material The online version of this article (10.1007/s10461-019-02537-1) contains supplementary material, which is available to authorized users.

Objectives The authors explored whether respondent-driven sampling (RDS) can generate a more diverse sample of black men who have sex with men (MSM) than time-location sampling (TLS) by comparing sample characteristics accrued by each method in two independent studies. Methods The first study exclusively recruited black MSM through RDS (N=256), while the second recruited MSM through TLS including a subsample of black MSM (N=69). Crude and adjusted point estimates and 95% CIs were calculated for socio-demographic and behavioural characteristics, HIV prevalence and prevalence of unrecognised infections, and were compared using the Z-test. Results The samples differed significantly regarding all socio-demographic and some behavioural characteristics. Compared with TLS, RDS estimated higher proportions of older, less educated, poorer, currently homeless and self-identified bisexual black MSM. Participants in RDS were less likely to have a main partner, had fewer male partners, were more likely to have a female partner and have both male and female partners, and reported greater methamphetamine, crack and heroin use. Prevalence of HIV and unrecognised infections were slightly higher among RDS participants. Conclusions The RDS sample comprised black MSM who were more diverse with respect to socio-demographic characteristics and may also be at higher risk for HIV. Thus, RDS has advantages in reaching higher risk black MSM who are most hidden from intervention research and service delivery. Future studies of black MSM using RDS could use steering strategies to recruit younger participants and other subgroups of greatest interest to public health and prevention.

Background The Republic of Cyprus is recognized as a low level HIV epidemic country with strong evidence of an increase in the transmission through the male to male sexual contact. Little is known about the factors that influence the sexual and HIV testing behavior in the Republic of Cyprus. Methods This is the first bio-behavioral study among men who have sex with men (MSM) in three major cities in the Republic of Cyprus, conducted between 2011 and 2012. Eligible participants were sampled in gay venues by using time-location sampling. Results Estimated HIV prevalence was 2.5%. The mean age of the sample was 29 ± 6.6 years old. One out of three MSM has not been tested for HIV in the last year. Multivariate logistic regression analysis revealed that the educational level (AOR 0.23, 95% CI 0.09-0.55), the cocaine use (AOR 3.78, 95% CI 1.21-11.83) as well as the type of sexual partner i.e. steady vs casual (AOR 0.18, 95% 0.08-0.45) were significantly associated with condom use in the last anal intercourse. Conclusions HIV prevalence among MSM in the Republic of Cyprus remains low; however more efforts are needed in order to increase HIV awareness and prevent the expansion of HIV epidemic in broader community.

Background Men who have sex with men (MSM) are highly vulnerable to HIV infection, but this population can be particularly difficult to reach in Central America due to stigma and violence. Knowing the size of populations at high risk for HIV and sexually transmitted infections (STI) is critical for informing prevention, care, and treatment programs. Simple approaches are needed to provide baseline estimates of the population size of MSM in Guatemala to advocate for appropriate resource allocation and programming. We compared population size estimates of MSM and transgender persons using capture-recapture linked to two differentsurveys that were developed concurrently using different sampling methodologies. Methods Capture recapture methods for estimating population size were integrated into two probability-based surveys using respondent driven sampling (RDS) and time-location sampling (TLS); conducted simultaneously among MSM in Guatemala City from October to December 2010. Key chains were used as uUnique objects in the form ofand study key chains were distributed approximately 1-month prior to the surveys in venues known to be frequented by MSM. Duplicate participation was avoided by using the same team to distribute the key chains and administering a set of questions before handing the object. Participants in the RDS and TLS surveys were asked, as part of the study interview, whether they had received the key chain. We assigned the number of key chains distributed in venues as the first capture and the proportion of participants that reported receiving the key chain in the RDS or TLS survey as the second capture. By applying standardised formulas for estimating population size using capture-recapture methods, we estimated the number of MSM in Guatemala City and 95% CIs around this estimate, adjusted for RDS and TLS sampling design. Results A total of 2128 key chains were distributed in the first capture. Of the 501 MSM interviewed in the RDS survey, 200 (RDS adjusted, 23.4%) had received the key chain. Thus the RDS adjusted estimated population size of MSM in Guatemala City was 9,190 (95% CI 7765 to 10 616). Of the 504 MSM interviewed in the TLS survey, 193 (TLS adjusted, 32.1%) had received the key chain. The TLS adjusted estimated number of MSM was 6620 (95% CI 5813 to 7427). Conclusions Estimates of MSM population size using the TLS survey resulted in a significantly lower estimate than that obtained through RDS survey, probably due to the fact that TLS targets MSM who attend venues. The estimate obtained through RDS may better reflect the size of the larger MSM population in Guatemala City, since this itRDS reaches MSM attending and not attending publicmeeting venues. Integrating capture-recapture methods in probability-based surveys among MSM is a simple and fast approach for providing the population sizes needed to inform and evaluate programs for MSM in Guatemala.

Time-space sampling (TSS; also referred to as time-location sampling, TLS) and respondent-driven sampling (RDS) are strategies that can be used for sampling hard-to-reach populations, for whom it is difficult to construct a sampling frame of the individual members of the population. With proper planning, execution, weighting, and analysis of relevant sampling-related data, both strategies have the potential to produce samples that are representative of the target populations. TSS is a probability-based strategy for recruiting members of a target population congregating at specific locations and times. RDS is predicated on the recognition that project participants are better able than project staff to locate and refer to the study site other potential participants; peers from the target population with whom they have an established relationship. Capture-recapture analysis can incorporate TSS and RDS data to estimate the size of a hard-to-reach population. TSS and RDS have been used extensively around the world in public health projects with populations at high risk for HIV infection. The collective experience gained from using TSS and RDS in HIV-related projects can be valuable in using these sampling strategies with other hard-to-reach populations in projects related to economics, political science, or sociology. Although TSS and RDS have specific strengths and limitations in terms of their abilities to produce valid results that enhance generalizability of findings, the choice of a particular sampling strategy depends on characteristics of the target population and the goal and resources of the project. Proper planning, monitoring, and evaluation of the sampling strategy and attention to logistical, regulatory, and ethical considerations are important to the successful implementation and effectiveness of the sampling strategy.