Abstract
BackgroundThe core-group theory of sexually transmitted infections suggests that targeting prevention to high-risk groups (HRG) could be very effective. We aimed to quantify the contribution of heterosexual HRGs and the potential impact of focused interventions to HIV transmission in the wider community.MethodsWe systematically identified studies published between 1980 and 2011. Studies were included if they used dynamical models of heterosexual HIV transmission, incorporated behavioural heterogeneity in risk, and provided at least one of the following primary estimates in the wider community (a) the population attributable fraction (PAF) of HIV infections due to HRGs, or (b) the number per capita or fraction of HIV infections averted, or change in HIV prevalence/incidence due to focused interventions.FindingsOf 267 selected articles, 22 were included. Four studies measured the PAF, and 20 studies measured intervention impact across 265 scenarios. In low-prevalence epidemics (≤5% HIV prevalence), the estimated impact of sex-worker interventions in the absence of risk compensation included: 6–100% infections averted; 0.9–6.2 HIV infections averted per 100,000 adults; 11–94% and 4–47% relative reduction in prevalence and incidence respectively. In high-prevalence epidemics (>5% HIV prevalence), sex-worker interventions were estimated to avert 6.8–40% of HIV infections and up to 564 HIV infections per 100,000 adults, and reduce HIV prevalence and incidence by 13–27% and 2–14% respectively. In both types of epidemics, greater heterogeneity in HIV risk was associated with a larger impact on the fraction of HIV infections averted and relative reduction in HIV incidence.ConclusionFocused interventions, as estimated by mathematical models, have the potential to reduce HIV transmission in the wider community across low- and high-prevalence regions. However, considerable variability exists in estimated impact, suggesting that a targeted approach to HIV prevention should be tailored to local epidemiological context.
Highlights
The concept of behavioural heterogeneity and core-groups has been critical to our understanding of how sexually transmitted infections (STI) are transmitted and persist in a population [1,2,3]
We systematically review published dynamic mathematical modelling studies of heterosexual HIV transmission which measured the contribution of High-risk group (HRG) or the potential impact of focused interventions
The findings from this review suggest that interventions focused on female sex workers (FSWs) could have an important role to play in high-prevalence epidemics
Summary
The concept of behavioural heterogeneity and core-groups has been critical to our understanding of how sexually transmitted infections (STI) are transmitted and persist in a population [1,2,3]. Infection moves from this ‘core-group’ to a wider population through a ‘bridge’ population [2,6] This bridge comprises men who have sex with sex workers and non-commercial partners. For heterosexual STI epidemics, other sources of heterogeneity include circular migration because of the potential for associated changes in partnerships as individuals travel back and forth between home and destination (for example, seasonal short-term migration for work) [7,8,9], casual multiple partnerships, and other concurrent partnerships outside of commercial sex. We aimed to quantify the contribution of heterosexual HRGs and the potential impact of focused interventions to HIV transmission in the wider community
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
