Counting hard-to-count populations: the network scale-up method for public health

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

Intervention Packages to Reduce the Impact of HIV and HCV Infections Among People Who Inject Drugs in Eastern Europe and Central Asia: A Modeling and Cost-effectiveness Study

Abstract Background: We evaluated the effectiveness and cost-effectiveness of interventions targeting hepatitis C virus (HCV) and HIV infections among people who inject drugs (PWID) in Eastern Europe/Central Asia. We specifically considered the needle-syringe program (NSP), opioid substitution therapy (OST), HCV and HIV diagnosis, antiretroviral therapy (ART), and/or new HCV treatment (direct acting antiviral [DAA]) in Belarus, Georgia, Kazakhstan, Republic of Moldova, and Tajikistan. Methods: We developed a deterministic dynamic compartmental model and evaluated the number of infections averted, costs, and incremental cost-effectiveness ratios (ICERs) of interventions. OST decreased frequencies of injecting by 85% and NSP needle sharing rates by 57%; ART was introduced at CD4 <350 and DAA at fibrosis stage ≥F2 at a $2370 to$23 280 cost. Results: Increasing NSP+OST had a high impact on transmissions (infections averted in PWID: 42% in Tajikistan to 55% in Republic of Moldova for HCV; 30% in Belarus to 61% in Kazakhstan for HIV over 20 years). Increasing NSP+OST+ART was very cost-effective in Georgia (ICER = $910/year of life saved [YLS]), and was cost-saving in Kazakhstan and Republic of Moldova. NSP+OST+ART and HIV diagnosis was very cost-effective in Tajikistan (ICER =$210/YLS). Increasing the coverage of all interventions was always the most effective strategy and was cost-effective in Belarus and Kazakhstan (ICER = $12 960 and$21 850/YLS); it became cost-effective/cost-saving in all countries when we decreased DAA costs. Conclusion: Increasing NSP+OST coverage, in addition to ART and HIV diagnosis, had a high impact on both epidemics and was very cost-effective and even cost-saving. When HCV diagnosis was improved, increased DAA averted a high number of new infections if associated with NSP+OST

Injecting behaviour and service use among young injectors in Albania, Moldova, Romania and Serbia.

BACKGROUND: This study examines socio-demographic profiles, injecting risk and use of health services among young injectors (15-24) in Albania, Moldova, Romania and Serbia. The objective was to provide age-disaggregated data to identify differences between adolescents (<18) and youth (18-24), and help fill the gap in knowledge on the youngest injectors in this region. METHODS: Cross sectional surveys were conducted in each country using chain-referral sampling to reach diverse networks of people who use drugs (PWID). In Albania and Romania, surveys were conducted in the capitals, respectively, Bucharest and Tirana. Respondents were recruited from 3 cities in Moldova (Chisinau, Balti and Tiraspol) and Serbia (Belgrade, Novi Sad and Nis). Data were collected on risk behaviours, service use and contact with police and other authorities. Analysis focused on associations between unsafe injecting behaviour and key determinants including demographic background, source of needles/syringes, use of harm reduction services and interactions with law enforcement. RESULTS: Although drug use and health-seeking varied across settings, sources of injecting equipment were significantly associated with sharing needles and syringes in Moldova, Romania and Serbia. Obtaining equipment from formal sources (pharmacies, needle-exchange programmes) reduced likelihood of sharing significantly, while being stopped by the police or incarcerated increased it. Adolescents relied on pharmacies more than public sector services to obtain equipment. CONCLUSION: Adolescents comprise a small proportion of PWID in this region, but have poorer access to harm reduction services than older peers. Engaging young PWID through private and public sector outlets might reduce unsafe practices, while use of the justice system to address drug use complicates efforts to reach this population

Narrating the social relations of initiating injecting drug use: transitions in self and society.

Few studies have explored drug injectors' accounts of their initiation of others into injecting. There also lacks research on the social relations of initiating injecting drug use in transitional society. We draw upon analyses of 42 audio-recorded semi-structured interviews with current and recent injecting drug users, conducted in 2009 in the Republic of Moldova, a transitional society of south-eastern Europe. A thematic analysis informed by narrative theory was undertaken, focusing on accounts of self-initiation and the initiation of others. We also reflect upon the potential of peer efforts to dissuade would-be injectors from initiating. Findings emphasise initiation into injecting as a symbolic identity transition, enabled through everyday social relations. In turn, our analysis locates the drug transitions of the self inside an account of societal transition. We find that personal narratives of self transition are made sense of, and presented, in relation to broader narratives of social transition and change. Furthermore, we explore how narratives of self-initiation, and especially the initiation of others, serve to negotiate initiation as a moral boundary crossing. Self-initiation is located inside an account of transitioning social values. In looking back, initiation is depicted as a feature of a historically situated aberration in normative values experienced by the 'transition generation'. Accounts of the initiation of others (which a third of our sample describe) seek to qualify the act as acceptable given the circumstances. These accounts also connect the contingency of agency with broader narratives of social condition. Lastly, the power of peers to dissuade others from initiating injection was doubted, in part because most self-initiations were accomplished as a product of agency enabled by environment as well as in the face of peer attempts to dissuade