Factors Associated with Productive Recruiting in a Respondent-Driven Sample of Men who Have Sex with Men in Vancouver, Canada

Respondent-driven sampling (RDS) has become a preferred sampling strategy for HIV research and surveillance in many global settings. Methodological investigation into the validity of RDS-generated samples has helped improve theoretical components of design. However, the operational challenges of implementing RDS remain underreported. 

We sought to identify factors independently associated with productive recruiting in an urban RDS-generated sample of gay, bisexual, and other men who have sex with men (MSM). Data were collected from the Momentum Health Study, a cohort of MSM recruited by RDS in Vancouver, Canada. Eligible men were given up to six RDS coupons to recruit their peers. 

The primary outcome was a count variable of each participant's number of eligible recruits. Multivariable Poisson regression identified independent predictors of productive recruitment. In total, 719 individuals comprised this analysis, of which 119 were seeds. The distribution of eligible recruits was right skewed, with 391 (54.4 %) having never recruited another participant and only eight participants (1.1 %) having recruited five. 

Significant, independent predictors of recruiting one additional participant included network size per ten unit increase (adjusted risk ratio [aRR] 1.03), being of Aboriginal race/ethnicity compared with White (aRR 1.51), being HIV-positive (aRR 1.31), being sexually active with only males (aRR 2.48), being single compared with common law/married (aRR 1.37), having recently read gay newspapers (aRR 1.58), having recently sought sex partners online (aRR 1.33) and being out to a male parent (aRR 1.30). 

This analysis demonstrates the importance of social network size in RDS adjustment, but also identifies other socio-demographic and behavioral variables that increased RDS coupon return, which may help researchers better operationalize the implementation of RDS.

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By:  Forrest JI1, Lachowsky NJ2,3, Lal A3, Cui Z3, Sereda P3, Raymond HF4,5, Ogilvie G2, Roth EA6, Moore D2,3, Hogg RS3,7.

• 1Faculty of Medicine, University of British Columbia, Vancouver, Canada. jamie.forrest@alumni.ubc.ca.
• 2Faculty of Medicine, University of British Columbia, Vancouver, Canada.
• 3British Columbia Centre for Excellence in HIV/AIDS, Vancouver, Canada.
• 4San Francisco Department of Public Health, San Francisco, USA.
• 5University of California San Francisco, San Francisco, USA.
• 6Department of Anthropology, University of Victoria, Victoria, Canada.
• 7Faculty of Health Sciences, Simon Fraser University, Burnaby, Canada. 
• J Urban Health. 2016 Mar 9. 

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Bio-Behavioural HIV & STI Surveillance among Men Who Have Sex with Men in Europe: The Sialon II Protocols

Background

Globally, the HIV epidemic continues to represent a pressing public health issue in Europe and elsewhere. There is an emerging and progressively urgent need to harmonise HIV and STI behavioural surveillance among MSM across European countries through the adoption of common indicators, as well as the development of trend analysis in order to monitor the HIV-STI epidemic over time. The Sialon II project protocols have been elaborated for the purpose of implementing a large-scale bio-behavioural survey among MSM in Europe in line with a Second Generation Surveillance System (SGSS) approach.

Methods/Design

Sialon II is a multi-centre biological and behavioural cross-sectional survey carried out across 13 European countries (Belgium, Bulgaria, Germany, Italy, Lithuania, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, and the UK) in community settings. A total of 4,966 MSM were enrolled in the study (3,661 participants in the TLS survey, 1,305 participants in the RDS survey). Three distinct components are foreseen in the study protocols: first, a preliminary formative research in each participating country. Second, collection of primary data using two sampling methods designed specifically for ‘hard-to-reach’ populations, namely Time Location Sampling (TLS) and Respondent Driven Sampling (RDS). Third, implementation of a targeted HIV/STI prevention campaign in the broader context of the data collection.

Discussion

Through the implementation of combined and targeted prevention complemented by meaningful surveillance among MSM, Sialon II represents a unique opportunity to pilot a bio-behavioural survey in community settings in line with the SGSS approach in a large number of EU countries. Data generated through this survey will not only provide a valuable snapshot of the HIV epidemic in MSM but will also offer an important trend analysis of the epidemiology of HIV and other STIs over time across Europe. Therefore, the Sialon II protocol and findings are likely to contribute significantly to increasing the comparability of data in EU countries through the use of common indicators and in contributing to the development of effective public health strategies and policies in areas of high need.

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By:  Lorenzo Gios, Massimo Mirandola, Igor Toskin, Ulrich Marcus, Sandra Dudareva-Vizule, Nigel Sherriff, Michele Breveglieri, Martina Furegato, Cinta Folch, Laia Ferrer, Alexandra Montoliu, Christiana Nöstlinger, Wim Vanden Berghe,Sharon Kühlmann-Berenzon, Inga Velicko, Sónia Dias, Barbara Suligoi, Vincenza Regine, Danica Stanekova,Magdalena Rosińska, Saulius Caplinskas, Irena Klavs, Ivailo Alexiev, and Alexandru Rafila

Veneto Region - Department of Health, CReMPE - Regional Coordination Centre for European Project Management, the Verona University Hospital, Verona, Italy

Department of Pathology, Infectious Diseases Section, the Verona University Hospital - Veneto Region, Verona, Italy

Department of Reproductive Health & Research, World Health Organization, Geneva, Switzerland

Department for Infectious Diseases Epidemiology, Robert Koch-Institute, Berlin, Germany

Centre for Health Research, University of Brighton, Brighton, UK

Institut Catala d’Oncologia (ICO), Centre for Epidemiological Studies on HIV/STI in Catalonia (CEEISCAT), Agencia de Salut Publica de Catalunya (ASPC), Hospital Universitari Germans Trias i Pujol, Barcelona, Spain

Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium

Department of Monitoring and Evaluation, Public Health Agency of Sweden, Solna, Sweden

Institute of Hygiene and Tropical Medicine & GHTM, Universidade Nova de Lisboa, Lisbon, Portugal

Centro Operativo AIDS, Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy

NRC for HIV/AIDS, Slovak Medical University, Bratislava, Slovak Republic

Department of Epidemiology, National Institute of Public Health, National Institute of Hygiene, Warsaw, Poland

Centre for Communicable Diseases and AIDS, Vilnius, Lithuania

National Institute of Public Health, Ljubljana, Slovenia

National Reference Laboratory of HIV, National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria

National Institute of Infectious Diseases Prof. Dr. Matei Bals, Bucharest, Romania

Lorenzo Gios, Email: moc.liamg@oznerol.soig, Email: ti.anorevinueladepso@soig.oznerol.

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HIV, HCV, HBV, HSV & Syphilis Prevalence among Female Sex Workers in Tehran, Iran, By Using Respondent-Driven Sampling

To find out the prevalence of HIV, HCV, HBV, HSV, and syphilis infections among female sex workers (FSWs) in Tehran, a cross-sectional study by using respondent-driven sampling (RDS) method was conducted. 

From December 2012 to April 2013 FSWs in Tehran were recruited. Inclusion criteria consisted of trading sex during the 12 months prior to this study and selling sex for at least 6 months in participants' lifetime. Among 161 consenting participants, 5% were infected with HIV. Moreover, 8.1% of FSWs were HCV positive, 37.9% were of HSV type1/type2, 1.2% of participants were infected with HBV, and none of the participants were infected with syphilis. 

HIV-positive participants were significantly more likely to be co-infected with HSV type1/type2, be younger, have more sexual partners and especially more clients during seven days prior to this study and report more history of having at least one of sexually transmitted infections symptoms in 12 months prior the study. 

In the multiple logistic regression analysis, being infected with HSV and also being under 25 years of age were found to be independently associated with HIV infection. Compared with the prevalence of HIV among general population of Tehran, relatively high prevalence of HIV and other viral infections among FSWs should be considered. A

ll in all, it is critical to commence effective counter-measures for this high-risk group if the aim is to prevent spreading of these viruses to general population.

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By:  Moayedi-Nia S1, Bayat Jozani Z1, Esmaeeli Djavid G1, Entekhabi F1, Bayanolhagh S1, Saatian M2, Sedaghat A3, Nikzad R1, Jahanjoo Aminabad F4, Mohraz M1.

• 1a Iranian Research Center for HIV/AIDS, Iranian Institute for Reduction of High-Risk Behaviors , Tehran University of Medical Sciences , Tehran , Iran.
• 2b Department of Pathology , Islamic Azad University Tehran Medical Branch , Tehran , Iran.
• 3c Center for Disease Control (CDC) of Iran, Ministry of Health and Medical Education , Tehran , Iran.
• 4d Department of Epidemiology and Biostatistics, School of Public Health , Tehran University of Medical Sciences , Tehran , Iran. 

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Respondent-Driven Sampling Estimators Under Real & Theoretical Recruitment Conditions of Female Sex Workers in China

We compare the performance of multiple respondent-driven sampling estimators under different sample recruitment conditions in hidden populations of female sex workers in the midst of China’s ongoing epidemic of sexually transmitted infections (STIs). We first examine empirically calibrated simulations grounded in survey data to evaluate the relative performance of each estimator under ideal sampling conditions consistent with respondent-driven sampling assumptions and under conditions that mimic observed respondent-driven sampling recruitment processes. One estimator, which incorporates respondents’ reports on their network of contacts, substantially out-performs the others under all conditions. We then apply the estimators to empirical samples of female sex workers collected in two Chinese cities which include unique data on respondents’ networks. These empirical results are consistent with the simulation results, suggesting that traditional respondent-driven sampling estimators overestimate the proportion of female sex workers working in low tiers of sex work and are likely to overstate the STI risk profiles of these populations.

Distributions of estimates of proportion in low tiers of sex work using the RDS2-VH estimator, by seeding and recruitment scenario. Notes: The population proportion is computed from the largest connected component of the simulated population network and is shown with a dashed vertical line. Population social network is priorities for local AIDS control efforts survey data source with venue size adjustments and weak geographic distribution of ties assumption (see eAppendix for description of population social networks). Distributions are plotted by kernel density estimation.

Below:  Distributions of estimates of proportion in low tiers of sex work in the real world recruitment scenario, by estimator. Notes: Dashed vertical line indicates the population proportion. Population social network is priorities for local AIDS control efforts survey data source with venue size adjustments and weak geographic distribution of ties assumption (see eAppendix for description of population social networks). Recruitment and seeding scenario is matched seeds and matched recruitments.

Full article at: http://goo.gl/wxNnft

By: Ashton M. Verdery,a,* M. Giovanna Merli,b James Moody,c,d Jeffrey Smith,e and Jacob C. Fisherf

^aDepartment of Sociology and Criminology, Population Research Institute, The Pennsylvania State University, University Park, Pennsylvania

^bDuke Population Research Institute, Sanford School of Public Policy, Department of Sociology, and Duke Global Health Institute, Duke University, Durham, NC

^cDuke Population Research Institute, Department of Sociology, Duke University, Durham, NC

^dKing Abdulaziz University, Jeddah, Saudi Arabia

^eDepartment of Sociology, University of Nebraska, Lincoln, NE

^fDepartment of Sociology, Duke University, Durham, NC

^*Corresponding Author. Department of Sociology and Criminology, 211 Oswald Tower, The Pennsylvania State University, University Park, PA 16802, Email: ude.usp@yredrev

   

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Implementation of Web-Based Respondent Driven Sampling among Men Who Have Sex with Men in Sweden

Respondent driven sampling (RDS) was designed to study 'hidden' populations, for which there are no available sampling frame. RDS has been shown to recruit far into social networks of the study population and achieve unbiased estimates when certain assumptions are fulfilled. Web-based respondent driven sampling (WebRDS) has been implemented among MSM in Vietnam and produced a sufficient sample of MSM. In order to see if WebRDS could work in a 'hidden' population in a high-income setting, we performed a WebRDS among MSM in Sweden to study a sensitive topic, sexual risk behaviour for HIV/STI and Internet use.

A cross-sectional survey was implemented between July 11, 2012 and January 21, 2013 by using a WebRDS software. Men, fifteen years old or above, who reported having ever had sex with another man were included. The web-survey explored sociodemographics, sexual risk behaviour for HIV/STI and Internet use.

The WebRDS process created a sample of 123 eligible respondents. The mean age among participants was 32 years old. All respondents reported having had unprotected anal intercourse (UAI) with at least one regular and one casual sex partner during the last 12 months. On average participants reported having had UAI with three casual sexual partners and in total having had seven casual sex partners during the last 12 months.

The WebRDS produced a sample of Internet-using MSM in Sweden who all reported sexual risk behaviour for HIV/STI during the last 12 months. It holds promise for future online studies among MSM and a possibility to reach MSM at risk for HIV/STI with interventions or information. Some challenges were found including short recruitment chains, and further research need to address how to optimize WebRDS online recruitment methods in high income settings.

Below: Use of online social networks among MSM respondents

Below:   MSM study participation per county in Sweden

Below:  WebRDS recruitment chains for 148 MSM participants

Below:  HIV/STI prevention resources usage among MSM respondents

Below:  Email Usage per week among MSM respondents

Full article at: http://goo.gl/79F77D

By: Strömdahl S1, Lu X2, Bengtsson L1, Liljeros F3, Thorson A1.

• 1Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden.
• 2Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden; College of Information System and Management, National University of Defense Technology, Changsha, China.
• 3Department of Sociology, Stockholm University, Stockholm, Sweden.

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If You Are Not Counted, You Don't Count: Estimating the Number of African-American Men Who Have Sex with Men in San Francisco Using a Novel Bayesian Approach

African-American men who have sex with men (AA MSM) have been disproportionately infected with and affected by HIV and other STIs in San Francisco and the USA. The true scope and scale of the HIV epidemic in this population has not been quantified, in part because the size of this population remains unknown. 

We used the successive sampling population size estimation (SS-PSE) method, a new Bayesian approach to population size estimation that incorporates network size data routinely collected in respondent-driven sampling (RDS) studies, to estimate the number of AA MSM in San Francisco. This method was applied to data from a 2009 RDS study of AA MSM. An estimate from a separate study of local AA MSM was used to model the prior distribution of the population size. Two-hundred and fifty-six AA MSM were included in the RDS survey. 

The estimated population size was 4917, using a flat prior estimated 1882 as a lower acceptable bound, and a large prior estimated 6762 as an acceptable upper bound. Point estimates from the SS-PSE were consistent with estimates from multiplier methods using external data. 

The SS-PSE method is easily integrated into RDS studies and therefore provides a simple and appealing tool to rapidly produce estimates of the size of key populations otherwise difficult to reach and enumerate.

Via: http://goo.gl/Zsz798 Purchase full article at: http://goo.gl/OfwN73

By: Wesson P1, Handcock MS2, McFarland W3, Raymond HF3.

• 1University of California, Berkeley, 101 Haviland Hall, Berkeley, CA, 94720-7358, USA
• 2University of California, Los Angeles, 8125 Mathematical Sciences Building, Los Angeles, CA, 90095-1554, USA.
• 3San Francisco Department of Public Health, 25 Van Ness Ave, Suite 500, San Francisco, CA, 94102, USA.

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A Comparison Between Respondent-Driven Sampling and Time-Location Sampling among Men Who Have Sex with Men in Shenzhen, China

Men who have sex with men (MSM) are a key population for HIV control and prevention in China. It is difficult to acquire representative samples of this hidden population. Respondent-driven sampling (RDS), based on peer referral, and time-location sampling (TLS) based on random selection of venue-day-time periods, are among the most commonly used sampling methods. However, differences in HIV-related characteristics of MSM recruited by these two methods have not been fully evaluated. 

We compared sociodemographics, risk behaviors, utilization of HIV-related intervention services, and HIV/syphilis infection rates between samples of 621 RDS MSM and 533 TLS MSM in Shenzhen, China in 2010. We found that the HIV prevalence was comparable in RDS and TLS MSM. TLS recruited larger proportions of more marginalized MSM than RDS: MSM recruited by TLS were older, less educated and more likely to be migrants (without Shenzhen hukou registration), to be non-gay identified and to engage in risky sexual behaviors. 

On the other hand, MSM recruited by TLS were more likely to have been covered by HIV-related intervention services. To conclude, in Shenzhen, TLS is more effective to reach the marginalized population of MSM. But because TLS can only reach MSM who physically attend venues and HIV-related intervention services are already commonly available at gay venues in Shenzhen, RDS is more informative for allocating prevention efforts than TLS. 

Furthermore, researchers and public health authorities should take into account the different sample compositions of RDS and TLS and apply sampling methods consistently when evaluating trends over time.

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By:  Zhao J1, Cai R, Chen L, Cai W, Yang Z, Richardus JH, de Vlas SJ.

• 1Shenzhen Center for Disease Control and Prevention, No. 8 Longyuan Road, Longzhu Avenue, Nanshan District, Shenzhen, 518055, China.

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Respondent-Driven Sampling as a Recruitment Method for Men Who Have Sex with Men in Southern Sub-Saharan Africa: A Cross-Sectional Analysis By Wave

Respondent-driven sampling (RDS) is a popular method for recruiting men who have sex with men (MSM). Our objective is to describe the ability of RDS to reach MSM for HIV testing in three southern African nations.

Data collected via RDS among MSM in Lesotho (N=318), Swaziland (N=310) and Malawi (N=334) were analysed by wave in order to characterise differences in sample characteristics. Seeds were recruited from MSM-affiliated community-based organisations. Men were interviewed during a single study visit and tested for HIV. χ² tests for trend were used to examine differences in the proportions across wave category.

A maximum of 13-19 recruitment waves were achieved in each study site. 

• The percentage of those who identified as gay/homosexual decreased as waves increased in Lesotho (49% to 27%). 
• In Swaziland and Lesotho, knowledge that anal sex was the riskiest type of sex for HIV transmission decreased across waves (39% to 23% and 37% to 19%). 
• The percentage of participants who had ever received more than one HIV test decreased across waves in Malawi (31% to 12%). 
• In Lesotho and Malawi, the prevalence of testing positive for HIV decreased across waves (48% to 15% and 23% to 11%). 
• Among those living with HIV, the proportion of those unaware of their status increased across waves in all study sites although this finding was not statistically significant.

RDS that extends deeper into recruitment waves may be a promising method of reaching MSM with varying levels of HIV prevention needs.

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By: Stahlman S1, Johnston LG2, Yah C3, Ketende S1, Maziya S4, Trapence G5, Jumbe V6, Sithole B7, Mothopeng T7, Mnisi Z8, Baral S1.

• 1Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Center for Public Health and Human Rights, Baltimore, Maryland, USA.
• 2Department of Global Health Sciences, University of California San Francisco, San Francisco, California, USA.
• 3Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Center for Public Health and Human Rights, Baltimore, Maryland, USA Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, South Africa.
• 4Rock of Hope, Manzini, Swaziland.
• 5Center for the Development of People, Blantyre, Malawi.
• 6Malawi College of Medicine, Blantyre, Malawi Centre for Global Health, Trinity College, Dublin, Ireland.
• 7Rock of Hope, Mbabane, Swaziland.
• 8Ministry of Health, Mbabane, Swaziland. 

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