A Two-stage Approach for Rapid Assessment of the Proportion Achieving Viral Suppression Using Routine Clinical Data.

BACKGROUND: Improving viral suppression among people with HIV reduces morbidity, mortality, and transmission. Accordingly, monitoring the proportion of patients with a suppressed viral load is important to optimizing HIV care and treatment programs. But viral load data are often incomplete in clinical records. We illustrate a two-stage approach to estimate the proportion of treated people with HIV who have a suppressed viral load in the Dominican Republic. METHODS: Routinely collected data on viral load and patient characteristics were recorded in a national database, but 74% of patients on treatment at the time of the study did not have a recent viral load measurement. We recruited a subset of these patients for a rapid assessment that obtained additional viral load measurements. We combined results from the rapid assessment and main database using a two-stage weighting approach and compared results to estimates obtained using standard approaches to account for missing data. RESULTS: Of patients with recent routinely collected viral load data, 60% had a suppressed viral load. Results were similar after applying standard approaches to account for missing data. Using the two-stage approach, we estimated that 77% (95% confidence interval [CI] = 74, 80) of those on treatment had a suppressed viral load. CONCLUSIONS: When assessing the proportion of people on treatment with a suppressed viral load using routinely collected data, applying standard approaches to handle missing data may be inadequate. In these settings, augmenting routinely collected data with data collected through sampling-based approaches could allow more accurate and efficient monitoring of HIV treatment program effectiveness.

HIV Prevalence and the HIV Treatment Cascade Among Female Sex Workers in Cross-Border Areas in East Africa.

In cross-border areas of East Africa, sexual networks include partnerships across resident, migrant, and mobile populations, and risky behaviors can coincide with fragmented health services given the challenges of cross-border coordination. Among those most at risk are female sex workers (FSWs). We map HIV prevalence among FSWs in 14 cross-border areas, estimate associations between FSW characteristics and HIV and undiagnosed HIV, and estimate progress towards the UNAIDS 90-90-90 targets. The 2016-2017 East Africa Cross-Border Integrated Health Study recruited 4040 women; 786 were classified as FSWs. Overall HIV prevalence among FSWs was 10.8% (95% CI 8.2%, 13.3%), though area-specific estimates varied considerably. Among FSWs living with HIV, 46.1% (95% CI 33.2%, 59.0%) knew their status, 80.6% (95% CI 66.3%, 94.9%) of FSWs who knew their status were on ART, and 84.8% (95% CI 66.1%, 100.0%) of FSWs on ART were virally suppressed. Results indicate a need for expanded HIV testing.

Increasing Men's Engagement in HIV Testing and Treatment Programs Through Crowdsourcing: A Mixed-Methods Analysis in Eswatini.

BACKGROUND: Sub-Saharan African HIV programs have had limited success in engaging men. Crowdsourcing contests may be a useful method to spur men's engagement in HIV services. We evaluated contributions and social media response to a crowdsourcing contest focused on increasing men's engagement in Eswatini HIV services. METHODS: We conducted a crowdsourcing contest to gain insight from the public on how HIV campaigns can more effectively engage young (20-40 years old) men in HIV services. Eligible submissions included images, songs, videos, and Internet memes. We used standard qualitative methods to examine textual themes from submissions. We examined social media response using Facebook analytics, comparing the number of people reached through crowdsourced HIV messages and the number of people reached through conventional HIV messages. RESULTS: We received 144 submissions from 83 participants. They represented 55 towns and all 4 regions of Eswatini. The contest page gained 461 followers on Facebook. Emergent themes included appealing to men's roles as protectors by suggesting that they need to take care of their own health to continue safeguarding their families. Crowdsourced messages reached a mean of 88 individuals across 4 posts; conventional messages reached a mean of 75 individuals across 4 posts. CONCLUSIONS: Crowdsourcing contest submissions provided insight on how to encourage men to engage in Eswatini HIV services. Crowdsourcing contests can be effective in collecting messages from men to create more locally relevant communication materials for HIV programs.

Differences in Access to HIV Services and Risky Sexual Behaviors Among Malawian Women at Social Venues Who Do and Do Not Engage in Sex Work.

In the high HIV-burden country of Malawi, female sex workers (FSW) are one of the populations most profoundly affected by HIV. The Malawi Priorities for Local AIDS Control Efforts (PLACE) surveyed 1,004 self-identified FSW, 213 other FSW (OFSW), and 130 other high risk women (OHRW) at social venues. Analyses compared the three groups using survey-weighted log binomial regression models. Each group had a distinct pattern of usage and access to services: OFSW and FSW had greater access to condoms, while using a condom ever was greatest among FSW. Nearly all women knew where to get tested for HIV but very few used FSW drop-in centers. HIV prevalence was high in all three groups (35% FSW, 20% OFSW, 20% OHRW). Given these results, HIV services should be targeted to all women at social venues in Malawi, regardless of sex worker status to improve health outcomes and limit onward transmission of HIV.

Estimating Hidden Population Sizes with Venue-based Sampling: Extensions of the Generalized Network Scale-up Estimator.

BACKGROUND: Researchers use a variety of population size estimation methods to determine the sizes of key populations at elevated risk of human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS), an important step in quantifying epidemic impact, advocating for high-risk groups, and planning, implementing, and monitoring prevention, care, and treatment programs. Conventional procedures often use information about sample respondents' social network contacts to estimate the sizes of key populations of interest. A recent study proposes a generalized network scale-up method that combines two samples-a traditional sample of the general population and a link-tracing sample of the hidden population-and produces more accurate results with fewer assumptions than conventional approaches. METHODS: We extended the generalized network scale-up method from link-tracing samples to samples collected with venue-based sampling designs popular in sampling key populations at risk of HIV. Our method obviates the need for a traditional sample of the general population, as long as the size of the venue-attending population is approximately known. We tested the venue-based generalized network scale-up method in a comprehensive simulation evaluation framework. RESULTS: The venue-based generalized network scale-up method provided accurate and efficient estimates of key population sizes, even when few members of the key population were sampled, yielding average biases below ±6% except when false-positive reporting error is high. It relies on limited assumptions and, in our tests, was robust to numerous threats to inference. CONCLUSIONS: Key population size estimation is vital to the successful implementation of efforts to combat HIV/AIDS. Venue-based network scale-up approaches offer another tool that researchers and policymakers can apply to these problems.

Estimating Sizes of Key Populations at the National Level: Considerations for Study Design and Analysis.

BACKGROUND: National estimates of the sizes of key populations, including female sex workers, men who have sex with men, and transgender women are critical to inform national and international responses to the HIV pandemic. However, epidemiologic studies typically provide size estimates for only limited high priority geographic areas. This article illustrates a two-stage approach to obtain a national key population size estimate in the Dominican Republic using available estimates and publicly available contextual information. METHODS: Available estimates of key population size in priority areas were augmented with targeted additional data collection in other areas. To combine information from data collected at each stage, we used statistical methods for handling missing data, including inverse probability weights, multiple imputation, and augmented inverse probability weights. RESULTS: Using the augmented inverse probability weighting approach, which provides some protection against parametric model misspecification, we estimated that 3.7% (95% CI = 2.9, 4.7) of the total population of women in the Dominican Republic between the ages of 15 and 49 years were engaged in sex work, 1.2% (95% CI = 1.1, 1.3) of men aged 15-49 had sex with other men, and 0.19% (95% CI = 0.17, 0.21) of people assigned the male sex at birth were transgender. CONCLUSIONS: Viewing the size estimation of key populations as a missing data problem provides a framework for articulating and evaluating the assumptions necessary to obtain a national size estimate. In addition, this paradigm allows use of methods for missing data familiar to epidemiologists.

The role of venues in structuring HIV, sexually transmitted infections, and risk networks among men who have sex with men.

BACKGROUND: Venues form part of the sampling frame for time-location sampling, an approach often used for HIV surveillance. While sampling location is often regarded as a nuisance factor, venues may play a central role in structuring risk networks. We investigated individual reports of risk behaviors and infections among men who have sex with men (MSM) attending different venues to examine structuring of HIV risk behaviors. However, teasing apart 'risky people' from 'risky places' is difficult, as individuals cannot be randomized to attend different venues. However, we can emulate this statistically using marginal structural models, which inversely weight individuals according to their estimated probability of attending the venue. METHODS: We conducted a cross-sectional survey of 609 MSM patrons of 14 bars in San Diego, California, recruited using the Priorities for Local AIDS Control Efforts (PLACE) methodology, which consists of a multi-level identification and assessment of venues for HIV risk through population surveys. RESULTS AND DISCUSSION: Venues differed by many factors, including participants' reported age, ethnicity, number of lifetime male partners, past sexually transmitted infection (STI), and HIV status. In multivariable marginal structural models, venues demonstrated structuring of HIV+ status, past STI, and methamphetamine use, independently of individual-level characteristics. CONCLUSIONS: Studies using time-location sampling should consider venue as an important covariate, and the use of marginal structural models may help to identify risky venues. This may assist in widespread, economically feasible and sustainable targeted surveillance and prevention. A more mechanistic understanding of how 'risky venues' emerge and structure risk is needed.

Can HIV service data be used for surveillance purposes?: a case study in Guangzhou, China.

BACKGROUND: Timely monitoring HIV epidemic among key populations is a formidable challenge. This study aimed to evaluate the agreement between data collected from an enhanced HIV sentinel surveillance (HSS+) and an HIV service, and to discuss whether testing service data can be used for surveillance purposes. METHODS: The HSS+ data were collected from HIV sentinel surveillance conducted annually among men who have sex with men (MSM) between 2009 and 2013 in Guangzhou, China. The HIV service data were obtained from the China-Bill & Melinda Gates Foundation Cooperation Program on HIV Prevention and Care (China-Gates HIV Program) in Guangzhou during the same period. The China-Gates HIV Program aimed to increase HIV counseling and testing among MSM. We compared demographic characteristics, condom use, HIV testing history, and the HIV status among individuals in these two datasets. The Armitage-trend test was used to evaluate the HIV epidemic and behaviors of the participants in the two datasets over the study period. RESULTS: Overall, a total of 2224 and 5311 MSM were included in the surveillance and service datasets, respectively. The majority of participants in the two datasets were between 20 and 29 years old, at least attended college, and had never been married. However, socio-demographic characteristics varied slightly between the two datasets. Similar trends were observed for the HIV epidemic in these two datasets. The surveillance dataset indicated that HIV prevalence increased from 3.9% in 2009 to 11.4% in 2013 (P-value for trend < 0.001), while data from the HIV service dataset indicated that MSM HIV prevalence during this same period increased from 6.2 to 8.9% (P-value for trend = 0.025). The rates of condom use were similar between the two datasets and remained consistent throughout the study period. CONCLUSION: HIV service data can complement existing HIV surveillance systems for MSM in China, though it may underestimate the HIV prevalence (HSS+ data contains people whose status is already know, while service data contains people who were initially negative or people of unknown status). HIV service data can be used for surveillance purposes, when prerequisite variables are collected from a large number people, if the quality assessment is conducted.

The Where and How for Reaching Transgender Women and Men Who Have Sex with Men with HIV Prevention Services in Guatemala.

This study aims to describe the transgender women and men who have sex with men (MSM) missed through venue-based sampling and illustrate how data on venues can be used to prioritize service delivery. Respondent-driven sampling (RDS) and time-location sampling (TLS) were used concurrently in 2010 for behavioral surveillance among MSM and transgender women in Guatemala City. RDS recruits who did not frequent venues (n = 106) were compared to TLS recruits (n = 609). TLS participants recruited at different types of venues were compared. RDS recruits who did not frequent venues were less educated, less likely to identify as gay, more likely to have concurrent partners and female sexual partners. Participants recruited at NGOs, saunas, hotels, streets and parks had more partners, were more likely to receive money for sex or have concurrent partners. Prevention programs for MSM and transgender women should characterize social venues and people that frequent them and improve service coverage through venues and social networks.

Brief non-commercial sexual encounters among patrons of entertainment venues in Liuzhou, China.

Brief non-commercial sexual encounters among patrons of social venues are increasing in China, but whether these encounters increase syphilis risk is unknown. We surveyed and tested 797 men and women at randomly selected social venues in urban Liuzhou and three surrounding counties. The percent reporting recent non-commercial one-time sex ranged from 14.5% of county women to 24.8% of urban men. 2.4% of men and 3.7% of women had a positive rapid syphilis test. Men reporting non-commercial one-time sex were significantly more likely to have a positive rapid syphilis test than other men (7.4 vs. 0.9%). Among women, commercial sex was more strongly associated with syphilis than non-commercial one-time sex (6.0 vs. 0.7%). Recent one-time sex was common and associated with syphilis among men. Venue-based HIV/STI prevention methods may be warranted among persons who do not engage in commercial sex, but frequently engage in one-time sex.

Exploring venue-associated risk: a comparison of multiple partnerships and syphilis infection among women working at entertainment and service venues.

The re-emerging syphilis epidemic in China is documented among sex workers, but little is known about STI risk among the broader group of women who work at entertainment and service venues, many of whom do not self-identify as sex workers. In 2009 in Liuzhou, China, community informants identified venues where people meet sexual partners. Characteristics of a stratified random sample of venues were collected during venue visits. Female staff at 42 venues were interviewed and tested for syphilis. The results showed that venue characteristics, worker behaviors, and syphilis prevalence differed by venue type. Service venue workers had more sexual partners, were more likely to report sex work, and more likely to have a positive syphilis test than entertainment venue workers (prevalence ratio: 5.4; 95% CI 1.4-20.6). To conclude, risk of syphilis differs by venue type and is higher at service venues, even among women who do not report commercial sex.

Biobehavioral survey using time location sampling among female sex workers living in Ghana in 2020.

Background: The HIV epidemic in Ghana is characterized as a mix of a low-level generalized epidemic with significant contributions from transmission among female sex workers (FSW) and their clients. This study seeks to identify and describe key characteristics and sexual behaviors of FSW and estimate the prevalence of HIV, syphilis, gonorrhea, chlamydia, and hepatitis B virus (HBV) among FSW in Ghana. Method: A total of 7,000 FSW were recruited for the study using Time Location Sampling (TLS) approach with 5,990 (85.6%) participants completing both biological and the behavioral aspects of the study. A structured questionnaire was administered to respondents to assess several factors, such as background characteristics, sexual risk behaviors, condom usage, HIV/AIDS knowledge, opinions, and attitudes. Trained staff conducted face-to-face interviews using mobile data collection software (REDCap) after provision of specimens for HIV and STI testing. Descriptive statistics such as medians, ranges, charts, and percentages are performed and presented. Also included, are bivariate analyses to establish relationships between FSW type and other relevant characteristics of the study. Results: Among the 7,000 (100%) FSW sampled from all regions, 6,773 took part in the behavioral and 6,217 the biological. There were 783 (11.2%) respondents who took part only in the behavioral and 227 (3.2%) only in the biological. Most were young, with a median age of 26 years, majority had never been married or were widowed/divorced and a quarter had no education or had only primary education. Majority (74.8%) of FSW first sold sex at age 25 years or less with a median age of 20 years. Most (84.8%) of the FSW indicated that they entered sex work for money, either for self or family and had an average of eleven (11) sexual partners per week. More than half (55.2%) of the FSW were new entrants who had been in sex work for less than 5 years before the study. Consistent condom use with paying clients was generally unsatisfactory (71%), and was however, very low (24%) with their intimate partners or boyfriends. Only about half (54.6%) of FSW have been exposed to HIV prevention services in the last three months preceding the survey, and this varies across regions. Overall, comprehensive knowledge about HIV and AIDS was low. Only 35% of FSW had comprehensive knowledge. HIV prevalence was 4.6% and was higher among seaters (brothel-based) and older FSW who had been sex work for a longer period. The HIV prevalence from the previous bio-behavioral survey (BBS) in 2015 and 2011 were estimated to be 6.9 and 11.1%, respectively. Conclusion: Compared to the results from the previous studies, the findings give an indication that Ghana is making significant progress in reducing the burden of HIV among FSW in the country. However, risky behaviors such as low consistent condom use, low coverage of HIV services across the regions, and low comprehensive knowledge could reverse the gains made so far. Immediate actions should be taken to expand coverage of HIV services to all locations. Efforts must be made to reach out to the new entrants while also addressing strongly held myths and misconceptions about HIV.

Use of routinely collected blood donation data for expanded HIV and Syphilis surveillance in Blantyre district, Malawi.

The World Health Organization recommends that all blood donations be screened for transfusion transmissible infections; these data are currently not incorporated into national disease surveillance efforts. We set out to use routinely collected data from blood donors in Blantyre district, Malawi to explore HIV and syphilis prevalence and identify sero-conversions among repeat donors. We conducted a retrospective cohort analysis of blood donation data collected by the Malawi Blood Transfusion Service from 2015 to 2021. All blood donations were routinely screened for HIV and syphilis. We characterized donor demographics as well as screening outcomes, including identifying sero-conversions among repeat donors who previously tested negative on their last donation. A total of 23,280 donations from 5,051 donors were recorded, with a median frequency of donations of 3 (IQR:2-6). Most donors were male (4,294; 85%) and students (3,262; 64.6%). Prevalence of HIV at first donation was 1.0% (52/5,051) and prevalence of syphilis was 1.6% (80/5,051); 52 HIV sero-conversions and 126 syphilis sero-conversions were identified, indicating an incidence rate per 1,000 person-years of 5.9 (95% CI: 4.7, 7.4) and 13.3 (95% CI:11.4, 15.4) respectively. Students had a lower prevalence of HIV and syphilis but higher risk of syphilis seroconversion. While blood donors are generally considered a low-risk population for HIV and syphilis, we were able to identify relatively high rates of undiagnosed HIV and syphilis infections among donors. Routinely collected data from national blood donation services may be used to better understand local HIV and syphilis epidemiology, with the potential to enhance disease surveillance systems. These findings may be used to identify priority prevention areas and populations in Blantyre district that can inform targeted interventions for improved disease prevention, testing and treatment.

Characterising HIV acquisition risk, treatment gaps and populations reached through venue-based outreach and clinical services in Blantyre, Malawi: findings from a district-wide CLOVE Study.

BACKGROUND: In 2017, Blantyre district had the highest adult HIV prevalence in Malawi (17.7%) and lowest viral suppression (60%). In response, the Ministry of Health expanded prevention and treatment services. We assessed whether outreach to social venues could identify individuals with increased HIV acquisition risk or with unsuppressed HIV not currently reached by clinic-based services. METHODS: We conducted a cross-sectional bio-behavioral survey in Blantyre, Malawi, from January to March 2022. We visited social venues where people meet new sexual partners and government clinics providing HIV testing or STI screening. Participants aged > 15 years were interviewed, and tested for HIV infection if not on ART. HIV recency tests were performed on those testing positive, and dried blood spots (DBS) was collected to quantify viral load and also to identify acute infection in those with HIV- results. RESULTS: HIV prevalence (18.5% vs 8.3%) and unsuppressed HIV infection (3.9% vs 1.7%) were higher among venue-recruited (n=1802) compared with clinic-recruited participants(n=2313). Among PLHIV at both clinics (n=199) and venues (n=289), 79% were virally suppressed. Few had acute(n=1) or recent infection(n=8). Among women, HIV prevalence was four times higher (38.9% venue vs 8.9% clinic). At clinics, PLHIV reporting visiting venues were less likely to be suppressed (54.6 vs 82.6%). More men at venues than at clinics reported paying for sex (49% vs 30%) or having multiple sex partners in the past 4 weeks (32% vs 16%). CONCLUSIONS: Enhanced venue-based prevention and testing for men and women could reduce treatment lapses, HIV treatment outcomes and reduce onward transmission.

From coitus to concurrency: sexual partnership characteristics and risk behaviors of 15-19 year old men recruited from urban venues in Tanzania.

Understanding the uptake and patterns of sexual partnerships of adolescent males reveals their risky behaviors that could persist into adulthood. Using venue-based sampling, we surveyed 671 male youth ages 15-19 from an urban Tanzanian neighborhood about their sexual partnerships during the past 6 months. The proportion of males who had ever had sex increased with age (21 % at age 15; 70 % at age 17; 94 % at age 19), as did the proportion who engaged in concurrency (5 % at age 15; 28 % at age 17; 44 % at age 19). Attendance at ≥2 social venues per day and meeting a sexual partner at a venue was associated with concurrency. Concurrency was associated with alcohol consumption before sex among 18-19 year olds and with not being in school among 15-17 year olds. We find that concurrency becomes normative over male adolescence. Venue-based sampling may reach youth vulnerable to developing risky sexual partnership patterns.

Social venues and HIV vulnerability of young venue workers: a cluster analysis of data from a national-level cross-sectional survey of social venues in Uganda.

OBJECTIVE: Venues where people socialize, such as bars, play a significant role in HIV transmission risk. However, little research has been done that identifies characteristics of high-risk venues, to inform HIV prevention efforts. This study identified clusters of social venues in Uganda and their relationship with HIV vulnerability of young venue workers (15-24 years). We also assessed availability of HIV prevention services at the venues. DESIGN AND SETTING: This was a secondary analysis of data from a larger cross-sectional survey of social venues in 25 districts of Uganda. PARTICIPANTS: A total of 480 venues that employed young workers were included in this study. ANALYSIS: Hierarchical cluster and mixed-effects regression analyses were conducted. RESULTS: Four clusters were adopted: cluster 1 represented 127 venues (mainly alcohol-serving sex work venues with a provision of on-site sex); cluster 2 represented 80 venues (mainly alcohol-serving sex work venues without a provision of on-site sex); cluster 3 represented 113 venues (mainly alcohol-serving venues without sex work or on-site sex); and cluster 4 represented 160 venues (non-alcohol-serving venues). We found a positive correlation between venue clusters and HIV vulnerability. Workers who belonged to cluster 1 (alcohol-serving sex work venues with a provision of on-site sex) had a 0.15 increase in HIV vulnerability compared with those in alcohol-serving venues without sex work or a provision of on-site sex (cluster 3) (coefficient: 0.15, 95% CI: 0.030 to 0.287) after adjusting for age, sex and marital status. Thirty-seven per cent of cluster 1 venues reported any HIV prevention services in the past 12 months. CONCLUSION: Alcohol-serving sex work venues with a provision of on-site sex (cluster 1) appeared to reinforce vulnerability to HIV in this study and should be targeted with HIV prevention interventions. Such venues can amplify HIV transmission by facilitating sexual partner coupling and on-site sex.

Clinic presentation delay and tuberculosis treatment outcomes in the Lake Victoria region of East Africa: A multi-site prospective cohort study.

In the Lake Victoria region of East Africa, little is known about delays between tuberculosis (TB) symptom onset and presentation at a clinic. Associations between clinic presentation delay and TB treatment outcomes are also poorly understood. In 2019, we abstracted data from routine TB treatment records for all adults (n = 776) initiating TB treatment in a 6-month period across 12 health facilities near Lake Victoria. We interviewed 301 cohort members and assessed whether they experienced a clinic presentation delay longer than 6 weeks. We investigated potential clinical and demographic correlates of clinic presentation delay and examined the association between clinic presentation delay and an unfavorable TB treatment outcome (death, loss to follow-up, or treatment failure). Clinic presentation delay was common, occurring among an estimated 54.7% (95% CI: 48.9%, 61.2%) of cohort members, though no specific correlates were identified. Clinic presentation delay was slightly associated with unfavorable TB treatment outcomes. The 180-day risk of an unfavorable outcome was 14.2% (95% CI: 8.0%, 20.4%) among those with clinic presentation delay, compared to 12.7% (95% CI: 5.1%, 20.3%) among those presenting earlier. Multi-level community-based interventions may be necessary to reduce clinic presentation delays in communities near Lake Victoria.

Geographic mobility and treatment outcomes among people in care for tuberculosis in the Lake Victoria region of East Africa: A multi-site prospective cohort study.

Geographic mobility may disrupt continuity of care and contribute to poor clinical outcomes among people receiving treatment for tuberculosis (TB). This may occur especially where health services are not well coordinated across international borders, particularly in lower and middle income country settings. In this work, we describe mobility and the relationship between mobility and unfavorable TB treatment outcomes (i.e., death, loss to follow-up, or treatment failure) among a cohort of adults who initiated TB treatment at one of 12 health facilities near Lake Victoria. We abstracted data from health facility records for all 776 adults initiating TB treatment during a 6-month period at the selected facilities in Kenya, Tanzania, and Uganda. We interviewed 301 cohort members to assess overnight travel outside one's residential district/sub-county. In our analyses, we estimated the proportion of cohort members traveling in 2 and 6 months following initiation of TB treatment, explored correlates of mobility, and examined the association between mobility and an unfavorable TB treatment outcome. We estimated that 40.7% (95% CI: 33.3%, 49.6%) of people on treatment for TB traveled overnight at least once in the 6 months following treatment initiation. Mobility was more common among people who worked in the fishing industry and among those with extra-pulmonary TB. Mobility was not strongly associated with other characteristics examined, however, suggesting that efforts to improve TB care for mobile populations should be broad ranging. We found that in this cohort, people who were mobile were not at increased risk of an unfavorable TB treatment outcome. Findings from this study can help inform development and implementation of mobility-competent health services for people with TB in East Africa.

A comparison of respondent-driven and venue-based sampling of female sex workers in Liuzhou, China.

OBJECTIVES: To compare two methods for sampling female sex workers (FSWs) for bio-behavioural surveillance. We compared the populations of sex workers recruited by the venue-based Priorities for Local AIDS Control Efforts (PLACE) method and a concurrently implemented network-based sampling method, respondent-driven sampling (RDS), in Liuzhou, China. METHODS: For the PLACE protocol, all female workers at a stratified random sample of venues identified as places where people meet new sexual partners were interviewed and tested for syphilis. Female workers who reported sex work in the past 4 weeks were categorised as FSWs. RDS used peer recruitment and chain referral to obtain a sample of FSWs. Data were collected between October 2009 and January 2010. We compared the socio-demographic characteristics and the percentage with a positive syphilis test of FSWs recruited by PLACE and RDS. RESULTS: The prevalence of a positive syphilis test was 24% among FSWs recruited by PLACE and 8.5% among those recruited by RDS and tested (prevalence ratio 3.3; 95% CI 1.5 to 7.2). Socio-demographic characteristics (age, residence and monthly income) also varied by sampling method. PLACE recruited fewer FSWs than RDS (161 vs 583), was more labour-intensive and had difficulty gaining access to some venues. RDS was more likely to recruit from areas near the RDS office and from large low prevalence entertainment venues. CONCLUSIONS: Surveillance protocols using different sampling methods can obtain different estimates of prevalence and population characteristics. Venue-based and network-based methods each have strengths and limitations reflecting differences in design and assumptions. We recommend that more research be conducted on measuring bias in bio-behavioural surveillance.

Systematic differences in risk behaviors and syphilis prevalence across types of female sex workers: a preliminary study in Liuzhou, China.

BACKGROUND: Female sex workers (FSWs) have become one of the key populations for HIV/STI control in China. Categorization of FSWs can help prioritize HIV/STI intervention efforts. We examined 2 possible categorizations of FSWs and the relationship with syphilis infection risk in Liuzhou City, China. METHODS: From October 2009 to February 2010, a total of 583 FSWs recruited by respondent-driven sampling in a cross-sectional survey were tested for syphilis and interviewed to collect sociodemographic and behavioral information. Respondents were categorized based on transaction price for vaginal sex and type of sex work location. The relationship between the 2 categorizations and syphilis infection risk was assessed using univariate and multivariate logistic regression analysis. RESULTS: The prevalence rates of lifetime and active syphilis infection were 8.6% and 4.1%, respectively. Lifetime and active syphilis prevalence was higher among FSWs in the lowest price category (52.7% and 25.4%, respectively) and those working in streets (69.7% and 39.8%, respectively) or through telephone (46.3% and 17.0%, respectively). Multivariate analysis showed that lifetime syphilis prevalence was significantly higher among street- (adjusted odds ratio [AOR]: 38.7, 95% confidence intervals [CI]: 10.7-139.9) and telephone-based FSWs (AOR: 10.8, 95% CI: 3.3-35.1), and that active syphilis prevalence was significantly higher among street-based FSWs (AOR: 15.2, 95% CI: 3.7-62.1) after adjusting for demographic and behavioral factors. CONCLUSIONS: Categorization based on sex work location was more closely related to the risk of syphilis infection than the price classification. Street- and telephone-based FSWs had significantly higher risk of syphilis infection. Focused interventions among these particular high-risk FSWs subgroups are warranted.