Estimating sizes of hidden or hard-to-reach populations is an important problem in public health. For example, estimates of the sizes of populations at highest risk for HIV and AIDS are needed for designing, evaluating and allocating funding for treatment and prevention programmes. A promising approach to size estimation, relatively new to public health, is the network scale-up method (NSUM), involving two steps: estimating the personal network size of the members of a random sample of a total population and, with this information, estimating the number of members of a hidden subpopulation of the total population. We describe the method, including two approaches to estimating personal network sizes (summation and known population). We discuss the strengths and weaknesses of each approach and provide examples of international applications of the NSUM in public health. We conclude with recommendations for future research and evaluation.

We present findings from a HIV survey using respondent driven sampling among 3,711 injecting drug users (IDUs) in 16 cities in Ukraine in 2008. Eligible participants were males and females who injected drugs in the past 1 month, ≥ 16 years and lived/worked in their respective interview area. The impact of injecting and sexual risk behaviors on HIV-infection were analyzed using four logistic models. Overall HIV prevalence was 32%. In the sexual risk model, paying for sex in the past 3 months and condom use during last sex increased the odds of HIV infection. Being female, having greater than 3 years of injection drug use, always sharing equipment and using alcohol with drugs in the past month remained significant in all four models. These findings indicate the urgent need to scale up peer education, needle exchange and methadone substitution programs for IDUs with specific programs targeting the needs of female injectors.

The HIV treatment cascade is an effective tool to track progress and gaps in the HIV response among key populations. People who inject drugs (PWID) remain the most affected key population in Ukraine with HIV prevalence of 22% in 2015. We performed secondary analysis of the 2017 Integrated Bio-Behavioral Surveillance (IBBS) survey data to construct the HIV treatment cascade for PWID and identify correlates of each indicator achievement. The biggest gap in the cascade was found in the first “90”, HIV status awareness: only 58% [95% CI: 56%-61%] of HIV-positive PWID reported being aware of their HIV-positive status. Almost 70% [67%-72%] of all HIV-infected PWID who were aware of their status reported that they currently received antiretroviral therapy (ART). Almost three quarters (74% [71%-77%]) of all HIV-infected PWID on ART were virally suppressed. Access to harm reduction services in the past 12 months and lifetime receipt of opioid agonist treatment (OAT) had the strongest association with HIV status awareness. Additionally, OAT patients who were aware of HIV-positive status had 1.7 [1.2–2.3] times the odds of receiving ART. Being on ART for the last 6 months or longer increased odds to be virally suppressed; in contrast, missed recent doses of ART significantly decreased the odds of suppression. The HIV treatment cascade analysis for PWID in Ukraine revealed substantial gaps at each step and identified factors contributing to achievement of the outcomes. More intensive harm reduction outreach along with targeted case finding could help to fill the HIV awareness gap among PWID in Ukraine. Scale up of OAT and community-level linkage to care and ART adherence interventions are viable strategies to improve ART coverage and viral suppression among PWID.

ObjectivesUkraine has one of the largest HIV epidemics in Europe, with high prevalence among female sex workers (FSWs). We aimed to identify factors associated with HIV testing and receipt of the test result in the last 12 months, HIV prevalence and self-reported positive status among FSWs in Ukraine.MethodsWe used data from an Integrated Bio-Behavioural Survey among FSWs conducted in 2013–2014. The survey methodology combined three sampling strategies: time and location sampling, respondent-driven sampling and key informant recruitment. We used multivariable regression to identify factors associated with self-reported HIV testing in the last 12 months, HIV prevalence and self-reported positive status among FSWs living with HIV. Explored factors included: age, age at first sex, age at entry into sex work, education, marital status, employment status beside sex work, condom use with last paying or non-paying sexual partner, drug or alcohol consumption and sex work venue.ResultsRecent HIV testing was low overall with only 63.2% of FSWs reported having tested and received their test result in the last 12 months prior to the survey. HIV prevalence was 7.1% overall, but only 45.0% of FSWs living with HIV were aware of their HIV status. Testing in the last 12 months with receipt of test result was less common among FSWs who used drugs ever in life (adjusted OR (AOR) 0.7, 95% CI 0.6 to 0.9), women soliciting clients indoors (AOR 0.8, 95% CI 0.7 to 0.9) and those not using a condom with last paying sexual partner (AOR 0.3, 95% CI 0.2 to 0.5). HIV positivity was associated with history of ever using drugs (AOR 2.3, 95% CI 1.4 to 3.6) and soliciting clients outdoors (AOR 1.5, 95% CI 1.1 to 2.0). Women working indoors were less aware of their positive status (AOR 0.1, 95% CI 0.1 to 0.9).ConclusionHIV prevalence is high among FSWs in Ukraine, and testing and knowledge of one’s status remain insufficient. HIV testing programmes need to expand with strategies to reach specific subgroups of FSWs.

The study examined trends in injection risk behaviors among people who inject drugs (PWIDs) and assessed the impact of harm reduction programs in Ukraine during [2007][2008][2009][2010][2011][2012][2013]. We performed a secondary analysis of the data collected in serial cross-sectional bio-behavioral surveillance surveys administered with PWIDs in Ukraine in 2007, 2008, 2011, and 2013. Using data from 14 Ukrainian cities, we assessed short-term trends in injection risk behaviors with the Cochran-Armitage test for trend and multivariable logistic regression models, adjusted for age, sex, region, marital status, education level, occupation, age at injection drug use initiation, experience of overdose, and self-reported HIV status. The overall test for trend indicated a statistically significant decrease over time for sharing needle/syringe during the last injection (p < 0.0001), sharing needle/syringe at least once in the last 30 days (p < 0.0001), and using a common container for drug preparation (p < 0.0001). The prevalence of injecting drugs from pre-loaded syringes was high (61.0%) and did not change over the study period. The observed reduction in the prevalence of injection risk behavior over time is encouraging. Our findings suggest that prevention programs in Ukraine have positive impact and provide support for governmental expansion of these programs.