Dimitri Prybylski

Incorporating the service multiplier method in respondent-driven sampling surveys to estimate the size of hidden and hard-to-reach populations: case studies from around the world.

Background Estimating the sizes of populations at highest risk for HIV is essential for developing and monitoring effective HIV prevention and treatment programs. We provide several country examples of how service multiplier methods have been used in respondent-driven sampling surveys and provide guidance on how to maximize this method’s use. Methods Population size estimates were conducted in 4 countries (Mauritius— intravenous drug users [IDU] and female sex workers [FSW]; Papua New Guinea—FSW and men who have sex with men [MSM]; Thailand—IDU; United States—IDU) using adjusted proportions of population members reporting attending a service, project or study listed in a respondent-driven sampling survey, and the estimated total number of population members who visited one of the listed services, projects, or studies collected from the providers. Results The median population size estimates were 8866 for IDU and 667 for FSW in Mauritius. Median point estimates for FSW were 4190 in Port Moresby and 8712 in Goroka, Papua New Guinea, and 2,126 for MSM in Port Moresby and 4200 for IDU in Bangkok, Thailand. Median estimates for IDU were 1050 in Chiang Mai, Thailand, and 15,789 in 2005 and 15,554 in 2009 in San Francisco. Conclusion Our estimates for almost all groups in each country fall within the range of other regional and national estimates, indicating that the service multiplier method, assuming all assumptions are met, can produce informative estimates. We suggest using multiple multipliers whenever possible, garnering program data from the widest possible range of services, projects, and studies. A median of several estimates is likely more robust to potential biases than a single estimate.

Unexpectedly high HIV prevalence among female sex workers in Bangkok, Thailand in a respondent-driven sampling survey.

The pattern of sex work in Thailand has shifted substantially over the last two decades from direct commercial establishments to indirect venues and non-venue-based settings. This respondent-driven sampling survey was conducted in Bangkok in 2007 among female sex workers (FSW) in non-venue-based settings to pilot a new approach to surveillance among this hidden population. Fifteen initial participants recruited 707 consenting participants who completed a behavioural questionnaire, and provided oral fluid for HIV testing, and urine for sexually transmitted infection (STI) testing. Overall HIV prevalence was 20.2% (95% confidence interval [CI] 16.3–24.7). Three-quarters of women were street-based (75.8%, 95% CI 69.9–81.1) who had an especially high HIV prevalence (22.7%, 95% CI 18.2–28.4); about 10 times higher than that found in routine sentinel surveillance among venue-based FSW (2.5%). STI prevalence (Chlamydia trachomatis and Neisseria gonorrhoeae) was 8.7% (95% CI 6.4–10.8) and 1.0% (95% CI 0.2–1.9), respectively. Lower price per sex act and a current STI infection were independently associated with HIV infection (P < 0.05). High HIV prevalence found among FSW participating in the survey, particularly non-venue-based FSW, identifies need for further prevention efforts. In addition, it identifies a higher-risk segment of FSW not reached through routine sentinel surveillance but accessible through this survey method.

Beyond Indicators: Advances in Global HIV Monitoring and Evaluation During the PEPFAR Era

Abstract: Monitoring and evaluation (M&E) is fundamental to global HIV program implementation and has been a cornerstone of the Presidents Emergency Plan for AIDS Relief (PEPFAR). Rapid results were crucial to demonstrating feasibility and scalability of HIV care and treatment services early in PEPFAR. When national HIV M&E systems were nascent, the rapid influx of funds and the emergency expansion of HIV services contributed to the development of uncoordinated “parallel” information systems to serve donor demands for information. Close collaboration of PEPFAR with multilateral and national partners improved harmonization of indicators, standards, methods, tools, and reports. Concurrent PEPFAR investments in surveillance, surveys, program monitoring, health information systems, and human capacity development began to show signs of progress toward sustainable country-owned systems. Awareness of the need for and usefulness of data increased, far beyond discussions of indicators and reporting. Emphasis has turned toward ensuring the quality of data and using available data to improve the quality of care. Assessing progress toward an AIDS-free generation requires that the global community can measure the reduction of new HIV infections in children and adults and monitor the coverage, quality, and outcomes of highly efficacious interventions in combination. Building national M&E systems requires sustained efforts over long periods of time with effective leadership and coordination. PEPFAR, in close collaboration with its global and national partners, is well positioned to transform the successes and challenges associated with early rapid scale-up into future opportunities for sustainable, cost-effective, country-owned programs and systems.

Diverse HIV epidemics among people who inject drugs in Thailand: Evidence from respondent-driven sampling surveys in Bangkok and Chiang Mai ☆

BACKGROUND Thailands long-standing HIV sero-sentinel surveillance system for people who inject drugs (PWID) is confined to those in methadone-based drug treatment clinics and representative data are scarce, especially outside of Bangkok. METHODS We conducted probability-based respondent-driven sampling (RDS) surveys in Bangkok (n=738) and Chiang Mai (n=309) to increase understanding of local HIV epidemics and to better inform the planning of evidence-based interventions. RESULTS PWID had different epidemiological profiles in these two cities. Overall HIV prevalence was higher in Bangkok (23.6% vs. 10.9%, p<0.001) but PWID in Bangkok are older and appear to have long-standing HIV infections. In Chiang Mai, HIV infections appear to be more recently acquired and PWID were younger and had higher levels of recent injecting and sexual risk behaviors with lower levels of intervention exposure. Methamphetamine was the predominant drug injected in both sites and polydrug use was common although levels and patterns of the specific drugs injected varied significantly between the sites. In multivariate analysis, recent midazolam injection was significantly associated with HIV infection in Chiang Mai (adjusted odds ratio=8.1; 95% confidence interval: 1.2-54.5) whereas in Bangkok HIV status was not associated with recent risk behaviors as infections had likely been acquired in the past. CONCLUSION PWID epidemics in Thailand are heterogeneous and driven by local factors. There is a need to customize intervention strategies for PWID in different settings and to integrate population-based survey methods such as RDS into routine surveillance to monitor the national response.

The importance of assessing self-reported HIV status in bio-behavioural surveys.

Abstract In bio-behavioural surveys measuring prevalence of infection with human immunodeficiency virus (HIV), respondents should be asked the results of their last HIV test. However, many government authorities, nongovernmental organizations, researchers and other civil society stakeholders have stated that respondents involved in such surveys should not be asked to self-report their HIV status. The reasons offered for not asking respondents to report their status are that responses may be inaccurate and that asking about HIV status may violate the respondents’ human rights and exacerbate stigma and discrimination. Nevertheless, we contend that, in the antiretroviral therapy era, asking respondents in bio-behavioural surveys to self-report their HIV status is essential for measuring and improving access to – and coverage of – services for the care, treatment and prevention of HIV infection. It is also important for estimating the true size of the unmet needs in addressing the HIV epidemic and for interpreting the behaviours associated with the acquisition and transmission of HIV infection correctly. The data available indicate that most participants in health-related surveys are willing to respond to a question about HIV status – as one of possibly several sensitive questions about sexual and drug use behaviours. Ultimately, normalizing the self-reporting of HIV status could help the global community move from an era of so-called exceptionalism to one of destigmatization – and so improve the epidemic response worldwide.

Gaps and opportunities: measuring the key population cascade through surveys and services to guide the HIV response

The UNAIDS 90‐90‐90 targets to diagnose 90% of people living with HIV, put 90% of them on treatment, and for 90% of them to have suppressed viral load have focused the international HIV response on the goal of eliminating HIV by 2030. They are also a constructive tool for measuring progress toward reaching this goal but their utility is dependent upon data availability. Though more than 25% of new infections are among key populations (KP)‐ sex workers, men who have sex with men, transgender people, people who inject drugs, and prisoners‐ and their sex partners, there is a dearth of treatment cascade data for KP. We assess the availability of cascade data and review the opportunities offered by biobehavioral and programme data to inform the HIV response.

Implementation of a Test, Treat, and Prevent HIV program among men who have sex with men and transgender women in Thailand, 2015-2016

Introduction Antiretroviral therapy reduces the risk of serious illness among people living with HIV and can prevent HIV transmission. We implemented a Test, Treat, and Prevent HIV Program among men who have sex with men (MSM) and transgender women at five hospitals in four provinces of Thailand to increase HIV testing, help those who test positive start antiretroviral therapy, and increase access to pre-exposure prophylaxis (PrEP). Methods We implemented rapid HIV testing and trained staff on immediate antiretroviral initiation at the five hospitals and offered PrEP at two hospitals. We recruited MSM and transgender women who walked-in to clinics and used a peer-driven intervention to expand recruitment. We used logistic regression to determine factors associated with prevalent HIV infection and the decision to start antiretroviral therapy and PrEP. Results During 2015 and 2016, 1880 people enrolled. Participants recruited by peers were younger (p<0.0001), less likely to be HIV-infected (p<0.0001), and those infected had higher CD4 counts (p = 0.04) than participants who walked-in to the clinics. Overall, 16% were HIV-positive: 18% of MSM and 9% of transgender women; 86% started antiretroviral therapy and 46% of eligible participants started PrEP. A higher proportion of participants at hospitals with one-stop HIV services started antiretroviral therapy than other hospitals. Participants who started PrEP were more likely to report sex with an HIV-infected partner (p = 0.002), receptive anal intercourse (p = 0.02), and receiving PrEP information from a hospital (p<0.0001). Conclusions We implemented a Test, Treat, and Prevent HIV Program offering rapid HIV testing and immediate access to antiretroviral therapy and PrEP. Peer-driven recruitment reached people at high risk of HIV and people early in HIV illness, providing an opportunity to promote HIV prevention services including PrEP and early antiretroviral therapy. Sites with one-stop HIV services had a higher uptake of antiretroviral therapy and PrEP.

Low Case Finding Among Men and Poor Viral Load Suppression Among Adolescents Are Impeding Namibia’s Ability to Achieve UNAIDS 90-90-90 Targets

Abstract Background In 2015, Namibia implemented an Acceleration Plan to address the high burden of HIV (13.0% adult prevalence and 216 311 people living with HIV [PLHIV]) and achieve the UNAIDS 90-90-90 targets by 2020. We provide an update on Namibia’s overall progress toward achieving these targets and estimate the percent reduction in HIV incidence since 2010. Methods Data sources include the 2013 Namibia Demographic and Health Survey (2013 NDHS), the national electronic patient monitoring system, and laboratory data from the Namibian Institute of Pathology. These sources were used to estimate (1) the percentage of PLHIV who know their HIV status, (2) the percentage of PLHIV on antiretroviral therapy (ART), (3) the percentage of patients on ART with suppressed viral loads, and (4) the percent reduction in HIV incidence. Results In the 2013 NDHS, knowledge of HIV status was higher among HIV-positive women 91.8% (95% confidence interval [CI], 89.4%–93.7%) than HIV-positive men 82.5% (95% CI, 78.1%–86.1%). At the end of 2016, an estimated 88.3% (95% CI, 86.3%–90.1%) of PLHIV knew their status, and 165 939 (76.7%) PLHIV were active on ART. The viral load suppression rate among those on ART was 87%, and it was highest among ≥20-year-olds (90%) and lowest among 15–19-year-olds (68%). HIV incidence has declined by 21% since 2010. Conclusions With 76.7% of PLHIV on ART and 87% of those on ART virally suppressed, Namibia is on track to achieve UNAIDS 90-90-90 targets by 2020. Innovative strategies are needed to improve HIV case identification among men and adherence to ART among youth.

Pretreatment HIV drug resistance among adults initiating ART in Namibia

Background Continued use of standardized, first-line ART containing NNRTIs and NRTIs may contribute to ongoing emergence of HIV drug resistance (HIVDR) in Namibia. Methods A nationally representative cross-sectional survey was conducted during 2015-16 to estimate the prevalence of significant pretreatment HIV drug resistance (PDR) and viral load (VL) suppression rates 6-12 months after initiating standardized first-line ART. Consenting adult patients (≥18 years) initiating ART were interviewed about prior antiretroviral drug (ARV) exposure and underwent resistance testing using dried blood spot samples. PDR was defined as mutations causing low-, intermediate- and high-level resistance to ARVs according to the 2014 WHO Surveillance of HIV Drug Resistance in Adults Initiating ART. The prevalence of PDR was described by patient characteristics, ARV exposure and VL results. Results were weighted to be nationally representative. Results Successful genotyping was performed for 381 specimens; 144 (36.6%) specimens demonstrated HIVDR, of which 54 (12.7%) demonstrated PDR. Resistance to NNRTIs was most prevalent (11.9%). PDR was higher in patients with previous ARV exposure compared with no exposure (30.5% versus 9.6%) (prevalence ratio = 3.17; P < 0.01). Conclusions This survey demonstrated overall PDR at >10% among adults initiating ART in Namibia. Patients with prior ARV exposure had higher rates of PDR. Introducing a non-NNRTI-based regimen for first-line ART should be considered to maximize benefit of ART and minimize the emergence of HIVDR.

Defining and surveying key populations at risk of HIV infection: Towards a unified approach to eligibility criteria for respondent-driven sampling HIV biobehavioral surveys:

Substantial resources are invested in human immunodeficiency virus biobehavioral surveys using respondent-driven sampling for measuring progress towards the UNAIDS 90–90–90 goals and to obtain other essential data on key populations. Survey data are used to meet country needs as well those of development partners, whose data needs may sometimes diverge. Surveys using differing eligibility criteria impede comparisons across surveys. With scant literature and guidelines on how to approach eligibility criteria, diverse criteria are used within and across countries. We conducted a review of peer-reviewed human immunodeficiency virus respondent-driven sampling biobehavioral survey literature published through December 2013. We describe eligibility criteria of 137 articles representing 214 surveys. Reporting on age, risk behavior, and reference period of risk behavior was nearly universal; however, reporting on gender, geography, and language was less common. Multiple definitions were used for each criterion, making comparisons challenging. We provide a framework for how to approach defining eligibility to improve consistency and comparability across surveys.