Kuantim mi tu ("Count me too"): Using Multiple Methods to Estimate the Number of Female Sex Workers, Men Who Have Sex With Men, and Transgender Women in Papua New Guinea in 2016 and 2017

Evaluation of Respondent-Driven Sampling Prevalence Estimators Using Real-World Reported Network Degree

Respondent-driven sampling (RDS) is used to measure trait or disease prevalence in populations that are difficult to reach and often marginalized. The authors evaluated the performance of RDS estimators under varying conditions of trait prevalence, homophily, and relative activity. They used large simulated networks (N = 20,000) derived from real-world RDS degree reports and an empirical Facebook network (N = 22,470) to evaluate estimators of binary and categorical trait prevalence. Variability in prevalence estimates is higher when network degree is drawn from real-world samples than from the commonly assumed Poisson distribution, resulting in lower coverage rates. Newer estimators perform well when the sample is a substantive proportion of the population, but bias is present when the population size is unknown. The choice of preferred RDS estimator needs to be study specific, considering both statistical properties and knowledge of the population under study.

Estimating the number of people who inject drugs using repeated respondent-driven sampling (RDS) in a community-based program: implications for the burden of hepatitis C and HIV infections and harm reduction coverage

Estimates of the population size of people who inject drugs (PWID) are essential for efficient program planning and for monitoring key targets. Existing estimates in Greece are based on the capture-recapture method applied to drug treatment sources. We aimed to obtain estimates based on data collected from a community-based program addressing PWID in Athens, Greece. The program was implemented in 2012-2013 to increase diagnosis and treatment for HIV among PWID during an HIV outbreak. Five Responden-Driven Sampling (RDS) rounds were used to recruit participants. A unique code was used to identify participants among rounds. Capture-recapture was applied to estimate the population size in 2013 (PWID with injection in the past 12 months; active PWID with injection in the past 30 days). Log-linear models were applied. In 2013, the estimated number of active PWID in Athens was 4,117 [95% confidence interval (CI): 3,728-4,507] (vs. 1,956 [95% CI: 1,525-2,565] the existing population size estimate). Based on this estimate, the coverage of needle and syringe programs in 2013 was 103 syringes/PWID/year (vs. 216 based on the existing estimate). The population prevalence of injecting drug use in Athens (past 12 months) was 0.222% (95% CI: 0.200-0.245). The inclusion of data from community-based programs in the estimation of the PWID population size resulted in 2.1-fold higher estimates, compared to the official estimates obtained from drug treatment data, and indicates the need for re-evaluation of necessary resources for harm reduction and elimination of HIV and hepatitis C in PWID.

Sexual and reproductive health needs and practices of female sex workers in Papua New Guinea: findings from a biobehavioral survey Kauntim mi tu (‘Count me too’)

Background

Little research has explored the sexual and reproductive health (SRH) experience of female sex workers (FSW), including girls aged < 18 years who are commercially sexually exploited (CSE), in Papua New Guinea (PNG). This paper describes the SRH history of FSW and CSE girls and factors associated with their use of moderately or highly effective contraceptive methods in three settings in PNG.

Methods

From 2016 to 2017, respondent-driven sampling (RDS) surveys were conducted among FSW and CSE girls in Port Moresby, Lae, and Mt. Hagen. FSW and CSE girls who were born female, aged ≥12 years, sold or exchanged vaginal sex in the past 6 months, spoke English or Tok Pisin, and had a valid RDS study coupon were eligible to participate. Interviews were conducted face-to-face and participants were offered rapid routine HIV and syphilis testing. Survey logistic regression procedures were used to identify factors associated with the use of moderately or highly effective contraceptive methods. Weighted data analysis was conducted.

Results

A total of 2901 FSW and CSE girls (Port Moresby, 673; Lae, 709; and Mt. Hagen, 709) were enrolled. The proportion using moderately or highly effective contraceptive methods was 37.7% in Port Moresby, 30.9% in Lae, and 26.5% in Mt. Hagen. After adjusting for covariates, factors significantly associated with the use of moderately or highly effective contraceptive methods in Port Moresby were being age 20–24, being married, being divorced or separated, having one or more dependent children, being away from home for more than 1 month in the last 6 months, and having tested HIV negative. No factors were significantly associated in Lae or Mt. Hagen. ANC attendance amongst FSW and CSE girls who gave birth in last 3 years was highest in Port Moresby at 91.2%. HIV testing was inconsistently and inadequately offered at ANC across the three cities.

Conclusions

Kauntim mi tu provides much-needed insight into the SRH experiences of FSW and CSE girls in PNG, where their use of moderately or highly effective contraceptive methods is low. We hope to shed light on the complicated reality they face due to illegality of sex work and multitude of complex healthcare experiences.

National and subnational size estimation of female sex workers in Ghana 2020: Comparing 3-source capture-recapture with other approaches

Background

Key Population size estimation (PSE) is instrumental for HIV/STI preventive, treatment and care services planning, implementation and delivery. The objective was to estimate the overall population of female sex workers (FSW) in all the 16 regions of Ghana using different PSE methods.

Method

Mapping of venues and complete enumeration of seaters was conducted at the formative stage prior to the bio-behavioral survey (BBS). Three PSE methods were used to derive the size estimates of FSW in the 16 regions. These include: Capture-recapture (CRC), service multiplier and three-source capture recapture (3SCRC) methods. The final choice of the estimation method used to estimate the roamer population was 3SCRC. This method was chosen because of its perfect record-linkage–hierarchic combination of three names that minimizes overmatching as well as the addition of an interaction term in the model which corrects for the dependencies in CRC.

Results

The total population size estimate of the female sex workers in the country obtained for roamers using capture re-capture was 41,746 (95% CI: 41,488–41,932). Using the service multiplier, the total population for both the roamers and seaters was 41,153 (95% CI: 37,242–45,984). The 3-source capture re-capture yielded 55,686 roamers FSW (95% CI: 47,686–63,686). The seater population was 4,363 FSW based on census/complete enumeration. The total population size estimate of FSW (seaters and roamers) in Ghana was 60,049 when 3SCRC and census were added. This represents about 0.76% of all estimated adult females aged 15-49yrs in Ghana.

Conclusion

We report population size estimates (PSE) for FSW in Ghana. These estimates are the results of 3SCRC. These findings provide a valid and reliable source of information that should be referenced by government officials and policymakers to plan, implement and provide HIV/STI preventive, treatment, and care services for FSW in Ghana.

Sexual health and wellbeing training with women in Pacific Island Countries and Territories: a scoping review

Background

Women who are spouses of students at a faith-based university in Papua New Guinea (PNG) are afforded proximal power. These women are perceived as leaders and regularly approached by members in their communities to provide advice on sexual and reproductive health matters. Women leaders therefore need access to sexual health information and training to provide appropriate advice.

Objective

The aim of this paper is to review the characteristics of community-based sexual health training in Pacific Island Countries and Territories (PICTs), as reported in published literature. This is evidence to inform the development of sexual health training programs for women in PNG.

Methods

A systematic search of databases, repositories and websites identified peer-reviewed studies. Grey literature was also sourced from government and non-government organisations and PNG health professionals. Six published papers, one report, one health worker practice manual and one health worker training package were identified for inclusion. Selected papers were assessed against the Canadian Hierarchy of Evidence to determine quality of evidence for practice. Themes were identified using a thematic analysis approach.

Results

Three themes became apparent from the literature synthesis: i) program development; ii) mode of delivery, and iii) evaluation. Social and cultural context influenced all elements of sexual health training in PICTs. Few studies reported evidence of comprehensive evaluation.

Conclusions

Successful sexual health training programs in PICT communities are designed and delivered accounting for local contexts. Programs that engage participants with diverse abilities inspire change to achieve desired outcomes. Key findings from this study can be used to assist women leaders to contextualise and operationalise sexual health training to promote the wellbeing of members in their communities.

A review of reported network degree and recruitment characteristics in respondent driven sampling implications for applied researchers and methodologists

OBJECTIVE

Respondent driven sampling (RDS) is an important tool for measuring disease prevalence in populations with no sampling frame. We aim to describe key properties of these samples to guide those using this method and to inform methodological research.

METHODS

In 2019, authors who published respondent driven sampling studies were contacted with a request to share reported degree and network information. Of 59 author groups identified, 15 (25%) agreed to share data, representing 53 distinct study samples containing 36,547 participants across 12 countries and several target populations including migrants, sex workers and men who have sex with men. Distribution of reported network degree was described for each sample and characteristics of recruitment chains, and their relationship to coupons, were reported.

RESULTS

Reported network degree is severely skewed and is best represented by a log normal distribution. For participants connected to more than 15 other people, reported degree is imprecise and frequently rounded to the nearest five or ten. Our results indicate that many samples contain highly connected individuals, who may be connected to at least 1000 other people.

CONCLUSION

Because very large reported degrees are common; we caution against treating these reports as outliers. The imprecise and skewed distribution of the reported degree should be incorporated into future RDS methodological studies to better capture real-world performance. Previous results indicating poor performance of regression estimators using RDS weights may be widely generalizable. Fewer recruitment coupons may be associated with longer recruitment chains.

Strategic options for syphilis control in Papua New Guinea- impact and cost-effectiveness projections using the syphilis interventions towards elimination (SITE) model

Objectives

Papua New Guinea (PNG) has among the highest rates of sexually transmitted infections (STIs) globally and is committed to reducing their incidence. The Syphilis Interventions Towards Elimination (SITE) model was used to explore the expected impact and cost of alternative syphilis intervention scale-up scenarios.

Methods

SITE is a dynamical model of syphilis transmission among adults 15-49 years. Individuals are divided into nine groups based on sexual behaviour and into six stages of infection. The model was calibrated to PNG using data from routine surveillance, bio-behavioural surveys, research studies and program records. Inputs included syphilis prevalence, risk behaviours, intervention coverage and service delivery unit costs. Scenarios compared different interventions (clinical treatment, contact tracing, syphilis screening, and condom promotion) for incidence and cost per infection averted over 2021-2030.

Results

Increasing treatment coverage of symptomatic primary/secondary-stage syphilis cases from 25-35% in 2020 to 60% from 2023 onwards reduced estimated incidence over 2021-2030 by 55%, compared to a scenario assuming constant coverage at 2019-2020 levels. The introduction of contact tracing in 2020, assuming 0.4 contacts per symptomatic person treated, reduced incidence over 2021-2030 by 10%. Increasing screening coverage by 20-30 percentage points from the 2019-2020 level reduced incidence over 2021-2030 by 3-16% depending on the target population. Scaling-up clinical, symptom-driven treatment and contact tracing had the lowest cost per infection averted, followed by condom promotion and periodic screening of female sex workers and men who have sex with men.

Conclusions

PNG could considerably reduce its syphilis burden by scaling-up clinical treatment and contact tracing alongside targeted behavioural risk reduction interventions. SITE is a useful tool countries can apply to inform national STI programming and resource allocation.

High prevalence of pulmonary tuberculosis among female sex workers, men who have sex with men, and transgender women in Papua New Guinea

Background

Papua New Guinea (PNG) has a tuberculosis (TB) case notification rate of 333 cases per 100,000 population in 2016 and is one of the 14 countries classified by the World Health Organization (WHO) as “high-burden” for TB, multi-drug-resistant TB (MDR-TB), and TB/HIV. HIV epidemic is mixed with a higher prevalence among key populations, female sex workers (FSW), men who have sex with men (MSM), and transgender women (TGW).

Methods

We conducted a cross-sectional HIV biobehavioral survey (BBS) using respondent-driven sampling method among FSW, MSM, and TGW in Port Moresby, Lae, and Mt. Hagen (2016–2017). As part of the study, participants were screened for the four symptoms suggestive of TB infection using the WHO TB screening algorithm. Sputum and venous whole blood samples were collected and tested for pulmonary TB and HIV infection, respectively. Pulmonary TB testing was performed using GeneXpert®MTB/RIF molecular point-of-care test, and HIV testing was done following the PNG national HIV testing algorithm. All data discussed are weighted unless otherwise mentioned.

Results

Among FSW, 72.6%, 52.0%, and 52.9% in Port Moresby, Lae, and Mt. Hagen, respectively, experienced at least one symptom suggestive of TB infection. Among MSM and TGW, 69% and 52.6% in Port Moresby and Lae, respectively, experienced at least one symptom suggestive of TB infection. Based on GeneXpert®MTB/RIF results, the estimated TB prevalence rate among FSW was 1200, 700, and 200 per 100,000 in Port Moresby, Lae, and Mt. Hagen, respectively. Among MSM and TGW, the estimated TB prevalence rate was 1000 and 1200 per 100,000 in Port Moresby and Lae, respectively. Co-prevalence of TB/HIV among FSW was 0.1% in Port Moresby and 0.2% in Lae. There were no co-prevalent cases among FSW in Mt. Hagen or among MSM and TGW in Port Moresby and Lae.

Conclusions

Key populations have a higher estimated rate of pulmonary TB than the national rate of pulmonary and extra-pulmonary TB combined. This showed that screening key populations for TB should be integrated into HIV programs regardless of HIV status in PNG’s national TB response.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41182-020-00293-w.

Population Size Estimation Methods: Searching for the Holy Grail

Accurate size estimates of key populations (eg, sex workers, people who inject drugs, transgender people, and men who have sex with men) can help to ensure adequate availability of services to prevent or treat HIV infection; inform HIV response planning, target setting, and resource allocation; and provide data for monitoring and evaluating program outcomes and impact. A gold standard method for population size estimation does not exist, but quality of estimates could be improved by using empirical methods, multiple data sources, and sound statistical concepts. To highlight such methods, a special collection of papers in JMIR Public Health and Surveillance has been released under the title “Key Population Size Estimations.” We provide a summary of these papers to highlight advances in the use of empirical methods and call attention to persistent gaps in information.

Confidential, accessible point-of-care sexual health services to support the participation of key populations in biobehavioural surveys: Lessons for Papua New Guinea and other settings where reach of key populations is limited

To achieve the UNAIDS 90-90-90 targets at a national level, many countries must accelerate service coverage among key populations. To do this, key population programs have adopted methods similar to those used in respondent-driven sampling (RDS) to expand reach. A deeper understanding of factors from RDS surveys that enhance health service engagement can improve key population programs. To understand the in-depth lives of key populations, acceptance of expanded point-of-care biological testing and determine drivers of participation in RDS surveys, we conducted semi-structured interviews with 111 key population participants (12-65 years) were purposefully selected from six biobehavioral surveys (BBS) in three cities in Papua New Guinea. Key populations were female sex workers, men who have sex with men, and transgender women. Four reasons motivated individuals to participate in the BBS: peer referrals; private, confidential, and stigma-free study facilities; "one-stop shop" services that provided multiple tests and with same-day results, sexually transmitted infection treatment, and referrals; and the desire to know ones' health status. Biobehavioral surveys, and programs offering key population services can incorporate the approach we used to facilitate key population engagement in the HIV cascade.