Publications
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Beyrer C, Crago A-L, Bekker L-G, et al., 2015, An action agenda for HIV and sex workers, LANCET, Vol: 385, Pages: 287-301, ISSN: 0140-6736
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- Citations: 154
Shannon K, Strathdee SA, Goldenberg SM, et al., 2015, Global epidemiology of HIV among female sex workers: influence of structural determinants, The Lancet, Vol: 385, Pages: 55-71, ISSN: 0140-6736
Female sex workers (FSWs) bear a disproportionately large burden of HIV infection worldwide. Despite decades of research and programme activity, the epidemiology of HIV and the role that structural determinants have in mitigating or potentiating HIV epidemics and access to care for FSWs is poorly understood. We reviewed available published data for HIV prevalence and incidence, condom use, and structural determinants among this group. Only 87 (43%) of 204 unique studies reviewed explicitly examined structural determinants of HIV. Most studies were from Asia, with few from areas with a heavy burden of HIV such as sub-Saharan Africa, Russia, and eastern Europe. To further explore the potential effect of structural determinants on the course of epidemics, we used a deterministic transmission model to simulate potential HIV infections averted through structural changes in regions with concentrated and generalised epidemics, and high HIV prevalence among FSWs. This modelling suggested that elimination of sexual violence alone could avert 17% of HIV infections in Kenya (95% uncertainty interval [UI] 1–31) and 20% in Canada (95% UI 3–39) through its immediate and sustained effect on non-condom use) among FSWs and their clients in the next decade. In Kenya, scaling up of access to antiretroviral therapy among FSWs and their clients to meet WHO eligibility of a CD4 cell count of less than 500 cells per μL could avert 34% (95% UI 25–42) of infections and even modest coverage of sex worker-led outreach could avert 20% (95% UI 8–36) of infections in the next decade. Decriminalisation of sex work would have the greatest effect on the course of HIV epidemics across all settings, averting 33–46% of HIV infections in the next decade. Multipronged structural and community-led interventions are crucial to increase access to prevention and treatment and to promote human rights for FSWs worldwide.
Malagon T, Drolet M, Boily M-C, et al., 2015, Changing Inequalities in Cervical Cancer: Modeling the Impact of Vaccine Uptake, Vaccine Herd Effects, and Cervical Cancer Screening in the Post-Vaccination Era, CANCER EPIDEMIOLOGY BIOMARKERS & PREVENTION, Vol: 24, Pages: 276-285, ISSN: 1055-9965
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- Citations: 11
Mitchell KM, Foss AM, Ramesh BM, et al., 2014, Relationship between exposure to the Avahan intervention and levels of reported condom use among men who have sex with men in southern India, BMC Public Health, Vol: 14, ISSN: 1471-2458
BackgroundThe Avahan intervention promotes consistent (100%) condom use amongst men who have sex with men in southern India. We assessed how condom use varies with intervention exposure for men who have sex with men in Bangalore.MethodsSelf-reported condom use and intervention exposure data were derived from a cross-sectional survey. Consistent condom use and condom use at last sex act with all, main, and casual male sex partners were assessed. Binary and continuous variables reflecting intervention exposure (including contact(s) with intervention staff, receiving condoms and seeing condom demonstrations) were used. Multivariable logistic regression was employed to assess the relationship between condom use with each type of partner and each exposure variable independently, controlling for socio-demographic and behavioural factors associated with condom use or intervention exposure.ResultsCondom use with all partners was higher among those who had ever been contacted by, received condoms from, or seen a condom demonstration by intervention staff (adjusted odds ratio >2, p < 0.02 for all). Consistent condom use with all types of partner increased with the number of condom demonstrations seen in the last month (adjusted odds ratio = 2.1 per demonstration, p < 0.025), while condom use at last sex act with a casual (but not main) partner increased with the number of condoms received from the intervention (adjusted odds ratio = 1.4 per condom, p = 0.04).ConclusionsDirect contact with Avahan program staff is associated with increased reported condom use among men who have sex with men in Bangalore. Reported consistent condom use and condom use at last sex act are associated with contacts involving demonstrations of correct condom use, and with receiving condoms, respectively.Keywords: Consistent condom use; Condom use at last sex act; Condom demonstration; Key population; Bangalore; Cross-secti
Vassall A, Chandrashekar S, Pickles M, et al., 2014, Community mobilisation and empowerment interventions as part of HIV prevention for female sex workers in southern India: a cost-effectiveness analysis, PLOS One, Vol: 9, ISSN: 1932-6203
BackgroundMost HIV prevention for female sex workers (FSWs) focuses on individual behaviour change involving peer educators, condom promotion and the provision of sexual health services. However, there is a growing recognition of the need to address broader societal, contextual and structural factors contributing to FSW risk behaviour. We assess the cost-effectiveness of adding community mobilisation (CM) and empowerment interventions (eg. community mobilisation, community involvement in programme management and services, violence reduction, and addressing legal policies and police practices), to core HIV prevention services delivered as part of Avahan in two districts (Bellary and Belgaum) of Karnataka state, Southern India.MethodsAn ingredients approach was used to estimate economic costs in US$ 2011 from an HIV programme perspective of CM and empowerment interventions over a seven year period (2004–2011). Incremental impact, in terms of HIV infections averted, was estimated using a two-stage process. An ‘exposure analysis’ explored whether exposure to CM was associated with FSW’s empowerment, risk behaviours and HIV/STI prevalence. Pathway analyses were then used to estimate the extent to which behaviour change may be attributable to CM and to inform a dynamic HIV transmission model.FindingsThe incremental costs of CM and empowerment were US$ 307,711 in Belgaum and US$ 592,903 in Bellary over seven years (2004–2011). Over a 7-year period (2004–2011) the mean (standard deviation, sd.) number of HIV infections averted through CM and empowerment is estimated to be 1257 (308) in Belgaum and 2775 (1260) in Bellary. This translates in a mean (sd.) incremental cost per disability adjusted life year (DALY) averted of US$ 14.12 (3.68) in Belgaum and US$ 13.48 (6.80) for Bellary - well below the World Health Organisation recommended willingness to pay threshold for India. When savings from ART are taken into account, investments in CM an
Laprise J-F, Drolet M, Boily M-C, et al., 2014, Comparing the cost-effectiveness of two- and three-dose schedules of human papillomavirus vaccination: A transmission-dynamic modelling study, VACCINE, Vol: 32, Pages: 5845-5853, ISSN: 0264-410X
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- Citations: 47
Dimitrov D, Boily M-C, Hallett TB, 2014, How Much Do We Know about Drug Resistance Due to PrEP Use? Analysis of Experts' Opinion and Its Influence on the Projected Public Health Impact, Symposium on HIV Research for Prevention (HIV R4P), Publisher: MARY ANN LIEBERT, INC, Pages: A161-A161, ISSN: 0889-2229
Panovska-Griffiths J, Vassall A, Prudden HJ, et al., 2014, Optimal allocation of resources in female sex worker targeted HIV prevention interventions: Model insights from Avahan in South India, PLOS One, Vol: 9, ISSN: 1932-6203
BackgroundThe Avahan programme has provided HIV prevention activities, including condom promotion, to female sex workers (FSWs) in southern India since 2004. Evidence suggests Avahan averted 202,000 HIV infections over 4 years. For replicating this intervention elsewhere, it is essential to understand how the intervention’s impact could have been optimised for different budget levels.MethodsBehavioural data were used to determine how condom use varied for FSWs with different levels of intervention intensity. Cost data from 64 Avahan districts quantified how district-level costs related to intervention scale and intensity. A deterministic model for HIV transmission amongst FSWs and clients projected the impact and cost of intervention strategies for different scale and intensity, and identified the optimal strategies that maximise impact for different budget levels.ResultsAs budget levels increase, the optimal intervention strategy is to first increase intervention intensity which achieves little impact, then scale-up coverage to high levels for large increases in impact, and lastly increase intensity further for small additional gains. The cost-effectiveness of these optimal strategies generally improves with increasing resources, while straying from these strategies can triple costs for the same impact. Projections suggest Avahan was close to being optimal, and moderate budget reductions (≥20%) would have reduced impact considerably (>40%).DiscussionOur analysis suggests that tailoring the design of HIV prevention programmes for FSWs can improve impact, and that a certain level of resources are required to achieve demonstrable impact. These insights are critical for optimising the use of limited resources for preventing HIV.
Mountain E, Pickles M, Mishra S, et al., 2014, The HIV care cascade and antiretroviral therapy in female sex workers: implications for HIV prevention, EXPERT REVIEW OF ANTI-INFECTIVE THERAPY, Vol: 12, Pages: 1203-1219, ISSN: 1478-7210
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- Citations: 34
Mountain E, Mishra S, Vickerman P, et al., 2014, Antiretroviral therapy uptake, attrition, adherence and outcomes among HIB-infected female sex workers: a systematic review and meta-analysis, PLOS One, Vol: 9, ISSN: 1932-6203
PurposeWe aimed to characterize the antiretroviral therapy (ART) cascade among female sex workers (FSWs) globally.MethodsWe systematically searched PubMed, Embase and MEDLINE in March 2014 to identify studies reporting on ART uptake, attrition, adherence, and outcomes (viral suppression or CD4 count improvements) among HIV-infected FSWs globally. When possible, available estimates were pooled using random effects meta-analyses (with heterogeneity assessed using Cochran's Q test and I2 statistic).Results39 studies, reporting on 21 different FSW study populations in Asia, Africa, North America, South America, and Central America and the Caribbean, were included. Current ART use among HIV-infected FSWs was 38% (95% CI: 29%–48%, I2 = 96%, 15 studies), and estimates were similar between high-, and low- and middle-income countries. Ever ART use among HIV-infected FSWs was greater in high-income countries (80%; 95% CI: 48%–94%, I2 = 70%, 2 studies) compared to low- and middle-income countries (36%; 95% CI: 7%–81%, I2 = 99%, 3 studies). Loss to follow-up after ART initiation was 6% (95% CI: 3%–11%, I2 = 0%, 3 studies) and death after ART initiation was 6% (95% CI: 3%–11%, I2 = 0%, 3 studies). The fraction adherent to ≥95% of prescribed pills was 76% (95% CI: 68%–83%, I2 = 36%, 4 studies), and 57% (95% CI: 46%–68%, I2 = 82%, 4 studies) of FSWs on ART were virally suppressed. Median gains in CD4 count after 6 to 36 months on ART, ranged between 103 and 241 cells/mm3 (4 studies).ConclusionsDespite global increases in ART coverage, there is a concerning lack of published data on HIV treatment for FSWs. Available data suggest that FSWs can achieve levels of ART uptake, retention, adherence, and treatment response comparable to that seen among women in the general population, but these data are from only a few research settings. More routine programme data on HIV treatment among FSWs across settings should be collected and disseminated
Vassall A, Pickles M, Chandrashekar S, et al., 2014, Cost-effectiveness of HIV prevention for high-risk groups at scale: an economic evaluation of the Avahan programme in south India, The Lancet Global Health, Vol: 2, Pages: e531-e540, ISSN: 2214-109X
BackgroundAvahan is a large-scale, HIV preventive intervention, targeting high-risk populations in south India. We assessed the cost-effectiveness of Avahan to inform global and national funding institutions who are considering investing in worldwide HIV prevention in concentrated epidemics.MethodsWe estimated cost effectiveness from a programme perspective in 22 districts in four high-prevalence states. We used the UNAIDS Costing Guidelines for HIV Prevention Strategies as the basis for our costing method, and calculated effect estimates using a dynamic transmission model of HIV and sexually transmitted disease transmission that was parameterised and fitted to locally observed behavioural and prevalence trends. We calculated incremental cost-effective ratios (ICERs), comparing the incremental cost of Avahan per disability-adjusted life-year (DALY) averted versus a no-Avahan counterfactual scenario. We also estimated incremental cost per HIV infection averted and incremental cost per person reached.FindingsAvahan reached roughly 150 000 high-risk individuals between 2004 and 2008 in the 22 districts studied, at a mean cost per person reached of US$327 during the 4 years. This reach resulted in an estimated 61 000 HIV infections averted, with roughly 11 000 HIV infections averted in the general population, at a mean incremental cost per HIV infection averted of $785 (SD 166). We estimate that roughly 1 million DALYs were averted across the 22 districts, at a mean incremental cost per DALY averted of $46 (SD 10). Future antiretroviral treatment (ART) cost savings during the lifetime of the cohort exposed to HIV prevention were estimated to be more than $77 million (compared with the slightly more than $50 million spent on Avahan in the 22 districts during the 4 years of the study).InterpretationThis study provides evidence that the investment in targeted HIV prevention programmes in south India has been cost effective, and is likely to be cost saving if a commitment i
Mitchell KM, Foss AM, Prudden HJ, et al., 2014, Who mixes with whom among men who have sex with men? Implications for modelling the HIV epidemic in southern India, Journal of Theoretical Biology, Vol: 355, Pages: 140-150, ISSN: 1095-8541
In India, the identity of men who have sex with men (MSM) is closely related to the role taken in anal sex(insertive, receptive or both), but little is known about sexual mixing between identity groups. Both rolesegregation (taking only the insertive or receptive role) and the extent of assortative (within-group)mixing are known to affect HIV epidemic size in other settings and populations. This study explores howdifferent possible mixing scenarios, consistent with behavioural data collected in Bangalore, south India,affect both the HIV epidemic, and the impact of a targeted intervention. Deterministic models describingHIV transmission between three MSM identity groups (mostly insertive Panthis/Bisexuals, mostlyreceptive Kothis/Hijras and versatile Double Deckers), were parameterised with behavioural data fromBangalore. We extended previous models of MSM role segregation to allow each of the identity groups tohave both insertive and receptive acts, in differing ratios, in line with field data. The models were used toexplore four different mixing scenarios ranging from assortative (maximising within-group mixing) todisassortative (minimising within-group mixing). A simple model was used to obtain insights into therelationship between the degree of within-group mixing, R0 and equilibrium HIV prevalence underdifferent mixing scenarios. A more complex, extended version of the model was used to compare the predicted HIV prevalence trends and impact of an HIV intervention when fitted to data from Bangalore.With the simple model, mixing scenarios with increased amounts of assortative (within-group) mixingtended to give rise to a higher R0 and increased the likelihood that an epidemic would occur. When thecomplex model was fit to HIV prevalence data, large differences in the level of assortative mixing wereseen between the fits identified using different mixing scenarios, but little difference was projected infuture HIV prevalence trends. An oral pre-exposure prophylaxis (P
Williams JR, Alary M, Lowndes CM, et al., 2014, Positive Impact of Increases in Condom Use among Female Sex Workers and Clients in a Medium HIV Prevalence Epidemic: Modelling Results from Project SIDA1/2/3 in Cotonou, Benin, PLOS One, Vol: 9, ISSN: 1932-6203
BackgroundA comprehensive, HIV prevention programme (Projet Sida1/2/3) was implemented among female sex workers (FSWs) in Cotonou, Benin, in 1993 following which condom use among FSWs increased threefold between 1993 and 2008 while FSW HIV prevalence declined from 53.3% to 30.4%.ObjectiveEstimate the potential impact of the intervention on HIV prevalence/incidence in FSWs, clients and the general population in Cotonou, Benin.Methods and FindingsA transmission dynamics model parameterised with setting-specific bio-behavioural data was used within a Bayesian framework to fit the model and simulate HIV transmission in the high and low-risk population of Cotonou and to estimate HIV incidence and infections averted by SIDA1/2/3. Our model results suggest that prior to SIDA1/2/3 commercial sex had contributed directly or indirectly to 93% (84–98%) of all cumulative infections and that the observed decline in FSWs HIV prevalence was more consistent with the self-reported post-intervention increase in condom use by FSWs than a counterfactual assuming no change in condom use after 1993 (CF-1). Compared to the counterfactual (CF-1), the increase in condom use may have prevented 62% (52–71%) of new HIV infections among FSWs between 1993 and 2008 and 33% (20–46%) in the overall population.ConclusionsOur analysis provides plausible evidence that the post-intervention increase in condom use during commercial sex significantly reduced HIV prevalence and incidence among FSWs and general population. Sex worker interventions can be effective even in medium HIV prevalence epidemics and need to be sustained over the long-term.
Mishra S, Pickles M, Blanchard JF, et al., 2014, Validation of the Modes of Transmission Model as a Tool to Prioritize HIV Prevention Targets: A Comparative Modelling Analysis, PLOS ONE, Vol: 9, ISSN: 1932-6203
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- Citations: 24
Shubber Z, Mishra S, Vesga JF, et al., 2014, The HIV Modes of Transmission model: a systematic review of its findings and adherence to guidelines, Journal of the International AIDS Society, Vol: 17, ISSN: 1758-2652
Introduction: The HIV Modes of Transmission (MOT) model estimates the annual fraction of new HIV infections (FNI) acquired by different risk groups. It was designed to guide country-specific HIV prevention policies. To determine if the MOT produced context-specific recommendations, we analyzed MOT results by region and epidemic type, and explored the factors (e.g. data used to estimate parameter inputs, adherence to guidelines) influencing the differences.Methods: We systematically searched MEDLINE, EMBASE and UNAIDS reports, and contacted UNAIDS country directors for published MOT results from MOT inception (2003) to 25 September 2012.Results: We retrieved four journal articles and 20 UNAIDS reports covering 29 countries. In 13 countries, the largest FNI (range 26 to 63%) was acquired by the low-risk group and increased with low-risk population size. The FNI among female sex workers (FSWs) remained low (median 1.3%, range 0.04 to 14.4%), with little variability by region and epidemic type despite variability in sexual behaviour. In India and Thailand, where FSWs play an important role in transmission, the FNI among FSWs was 2 and 4%, respectively. In contrast, the FNI among men who have sex with men (MSM) varied across regions (range 0.1 to 89%) and increased with MSM population size. The FNI among people who inject drugs (PWID, range 0 to 82%) was largest in early-phase epidemics with low overall HIV prevalence. Most MOT studies were conducted and reported as per guidelines but data quality remains an issue.Conclusions: Although countries are generally performing the MOT as per guidelines, there is little variation in the FNI (except among MSM and PWID) by region and epidemic type. Homogeneity in MOT FNI for FSWs, clients and low-risk groups may limit the utility of MOT for guiding country-specific interventions in heterosexual HIV epidemics.
Jit M, Choi YH, Laprise J-F, et al., 2014, Two-dose strategies for human papillomavirus vaccination: How well do they need to protect?, VACCINE, Vol: 32, Pages: 3237-3242, ISSN: 0264-410X
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- Citations: 20
Drolet M, Laprise J-F, Boily M-C, et al., 2014, Potential cost-effectiveness of the nonavalent human papillomavirus (HPV) vaccine, INTERNATIONAL JOURNAL OF CANCER, Vol: 134, Pages: 2264-2268, ISSN: 0020-7136
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- Citations: 54
Boily M-C, Shubber Z, 2014, Modelling in concentrated epidemics: informing epidemic trajectories and assessing prevention approaches, CURRENT OPINION IN HIV AND AIDS, Vol: 9, Pages: 134-149, ISSN: 1746-630X
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- Citations: 10
Boily M-C, Shubber Z, 2014, Modelling in concentrated epidemics: informing epidemic trajectories and assessing prevention approaches., Curr Opin HIV AIDS, Vol: 9, Pages: 134-149
PURPOSE OF THE REVIEW: This review summarizes recent mathematical modelling studies conducted among key populations including MSM, people who inject drugs (PWID), and female sex workers (FSWs) in low prevalence settings used as a marker of concentrated epidemics. RECENT FINDINGS: Most recent studies focused on MSM, Asian settings or high-income countries, studied the transmission dynamics or modelled pre-exposure prophylaxis, treatment as prevention or behavioural interventions specific to each key population (e.g., needle exchange programme or use of low-dead space syringes for PWID). Biological interventions were deemed effective and cost-effective, though still expensive, and often deemed unlikely to result in HIV elimination if used alone. Targeting high-risk individuals even within key populations improved efficiency. Some studies made innovative use of models to formally evaluate HIV prevention programmes, to interpret genetic or co-infection data, and to address methodological questions and validate epidemiological tools. CONCLUSION: More work is needed to optimize combination prevention focusing on key populations in different settings. The gaps identified include the limited number of studies modelling drug resistance, structural interventions, treatment as prevention among FSWs, and estimating the contribution of key populations to overall transmission in different settings.
Mishra S, Pickles M, Blanchard JF, et al., 2014, Distinguishing sources of HIV transmission from the distribution of newly acquired HIV infections: why is it important for HIV prevention planning?, SEXUALLY TRANSMITTED INFECTIONS, Vol: 90, Pages: 19-25, ISSN: 1368-4973
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- Citations: 26
Eaton JW, Menzies NA, Stover J, et al., 2014, Health benefits, costs, and cost-effectiveness of earlier eligibility for adult antiretroviral therapy and expanded treatment coverage: a combined analysis of 12 mathematical models, The Lancet Global Health, Vol: 2, Pages: E23-E34, ISSN: 2214-109X
BackgroundNew WHO guidelines recommend initiation of antiretroviral therapy for HIV-positive adults with CD4 counts of 500 cells per μL or less, a higher threshold than was previously recommended. Country decision makers have to decide whether to further expand eligibility for antiretroviral therapy accordingly. We aimed to assess the potential health benefits, costs, and cost-effectiveness of various eligibility criteria for adult antiretroviral therapy and expanded treatment coverage.MethodsWe used several independent mathematical models in four settings—South Africa (generalised epidemic, moderate antiretroviral therapy coverage), Zambia (generalised epidemic, high antiretroviral therapy coverage), India (concentrated epidemic, moderate antiretroviral therapy coverage), and Vietnam (concentrated epidemic, low antiretroviral therapy coverage)—to assess the potential health benefits, costs, and cost-effectiveness of various eligibility criteria for adult antiretroviral therapy under scenarios of existing and expanded treatment coverage, with results projected over 20 years. Analyses assessed the extension of eligibility to include individuals with CD4 counts of 500 cells per μL or less, or all HIV-positive adults, compared with the previous (2010) recommendation of initiation with CD4 counts of 350 cells per μL or less. We assessed costs from a health-system perspective, and calculated the incremental cost (in US$) per disability-adjusted life-year (DALY) averted to compare competing strategies. Strategies were regarded very cost effective if the cost per DALY averted was less than the country's 2012 per-head gross domestic product (GDP; South Africa: $8040; Zambia: $1425; India: $1489; Vietnam: $1407) and cost effective if the cost per DALY averted was less than three times the per-head GDP.FindingsIn South Africa, the cost per DALY averted of extending eligibility for antiretroviral therapy to adult patients with CD4 counts of 500 cells per &
Mishra S, Mountain E, Pickles M, et al., 2014, Exploring the population-level impact of antiretroviral treatment: the influence of baseline intervention context, AIDS, Vol: 28, Pages: S61-S72, ISSN: 0269-9370
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- Citations: 14
Dimitrov D, Boily M-C, Brown ER, et al., 2013, Analytic Review of Modeling Studies of ARV Based PrEP Interventions Reveals Strong Influence of Drug-Resistance Assumptions on the Population-Level Effectiveness, PLOS One, Vol: 8, ISSN: 1932-6203
BackgroundFour clinical trials have shown that oral and topical pre-exposure prophylaxis (PrEP) based on tenofovir may be effective in preventing HIV transmission. The expected reduction in HIV transmission and the projected prevalence of drug resistance due to PrEP use vary significantly across modeling studies as a result of the broad spectrum of assumptions employed. Our goal is to quantify the influence of drug resistance assumptions on the predicted population-level impact of PrEP.MethodsAll modeling studies which evaluate the impact of oral or topical PrEP are reviewed and key assumptions regarding mechanisms of generation and spread of drug-resistant HIV are identified. A dynamic model of the HIV epidemic is developed to assess and compare the impact of oral PrEP using resistance assumptions extracted from published studies. The benefits and risks associated with ten years of PrEP use are evaluated under identical epidemic, behavioral and intervention conditions in terms of cumulative fractions of new HIV infections prevented, resistance prevalence among those infected with HIV, and fractions of infections in which resistance is transmitted.ResultsPublished models demonstrate enormous variability in resistance-generating assumptions and uncertainty in parameter values. Depending on which resistance parameterization is used, a resistance prevalence between 2% and 44% may be expected if 50% efficacious oral PrEP is used consistently by 50% of the population over ten years. We estimated that resistance may be responsible for up to a 10% reduction or up to a 30% contribution to the fraction of prevented infections predicted in different studies.ConclusionsResistance assumptions used in published studies have a strong influence on the projected impact of PrEP. Modelers and virologists should collaborate toward clarifying the set of resistance assumptions biologically relevant to the PrEP products which are already in use or soon to be added to the arsenal against
Owen BN, Brock PM, Shubber Z, et al., 2013, 31. Lifetime prevalence of anal intercourse among sexually active female youth and young female sex workers: a comparative systematic review and meta-analysis., ISSN: 1448-5028
Background Anal cancer incidence has increased over the past twenty years. Heterosexual anal intercourse (AI) is a risk factor for HPV and HIV infection but is under-researched and ill-understood. We compare AI practices among young, sexually active general population females and female sex workers (FSW). Methods: We searched PubMed for heterosexual AI studies among young females, including FSWs (mean age <25 years), to December 2012. Study estimates were pooled using a random-effects model. Results: Fifty-four studies (42 average-risk, 6 higher-risk, 6 FSWs) were included. Most studies among general population youth were conducted in North America using self-administered questionnaires. All FSW studies were conducted in Africa and Asia using face-to-face interviews (FTFI). Pooled estimates of lifetime AI prevalence were larger among average-risk (23.6%, 95% CI 20.4-26.7) and higher-risk youth (25.5%, 95% CI 11.7-39.2) than FSWs (12.8%, 95% CI 8.4-17.3), but highly heterogeneous (I2 >90%). However, pooled AI estimates by continent of average-risk youth (Asia=13.9%, 95% CI=1.7-29.5; Africa=18.4%, 95% CI 0.9-35.8) were more similar to those of FSWs (Asia=16.0%, 95% CI 10.3-21.6; Africa=9.7%, 95% CI 3.8-15.7). Estimates of average-risk youth reporting via FTFI (12.1%, 95% CI 0.7-23.5) were likewise similar to those among FSWs (12.8%, 95% CI 8.4-17.3). Pooled AI prevalence estimates among FSWs were higher in studies conducted after 2001 than in earlier studies. Conclusions: AI is common among sexually active females and may be increasing; it could therefore be an important determinant of HPV transmission and anal cancers. AI is as or more common among the general population youth than young FSWs but this may be confounded by continent, interview method and other unmeasured variables.
Pickles M, Boily M-C, Vickerman P, et al., 2013, Assessment of the population-level effectiveness of the Avahan HIV-prevention programme in South India: a preplanned, causal-pathway-based modelling analysis, LANCET GLOBAL HEALTH, Vol: 1, Pages: E289-E299, ISSN: 2214-109X
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- Citations: 52
Behanzin L, Diabate S, Minani I, et al., 2013, Assessment of HIV-related risky behaviour: a comparative study of face-to-face interviews and polling booth surveys in the general population of Cotonou, Benin, SEXUALLY TRANSMITTED INFECTIONS, Vol: 89, Pages: 595-601, ISSN: 1368-4973
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- Citations: 20
Dimitrov D, Boily M-C, Marrazzo J, et al., 2013, Population-Level Benefits from Providing Effective HIV Prevention Means to Pregnant Women in High Prevalence Settings, PLOS One, Vol: 8, ISSN: 1932-6203
BackgroundHIV prevalence among pregnant women in Southern Africa is extremely high. Epidemiological studies suggest that pregnancy increases the risk of HIV sexual acquisition and that HIV infections acquired during pregnancy carry higher risk of mother-to-child transmission (MTCT). We analyze the potential benefits from extending the availability of effective microbicide to pregnant women (in addition to non-pregnant women) in a wide-scale intervention.Methods and FindingsA transmission dynamic model was designed to assess the impact of microbicide use in high HIV prevalence settings and to estimate proportions of new HIV infections, infections acquired during pregnancy, and MTCT prevented over 10 years. Our analysis suggests that consistent use of microbicide with 70% efficacy by 60% of non-pregnant women may prevent approximately 40% and 15% of new infections in women and men respectively over 10 years, assuming no additional increase in HIV risk to either partner during pregnancy (RRHIV/preg = 1). It may also prevent 8–15% MTCT depending on the increase in MTCT risk when HIV is acquired during pregnancy compared to before pregnancy (RRMTCT/preg). Extending the microbicides use during pregnancy may improve the effectiveness of the intervention by 10% (RRHIV/preg = 1) to 25% (RRHIV/preg = 2) and reduce the number of HIV infections acquired during pregnancy by 40% to 70% in different scenarios. It may add between 6% (RRHIV/preg = 1, RRMTCT/preg = 1) and 25% (RRHIV/preg = 2, RRMTCT/preg = 4) to the reduction in the residual MTCT.ConclusionProviding safe and effective microbicide to pregnant women in the context of wide-scale interventions would be desirable as it would increase the effectiveness of the intervention and significantly reduce the number of HIV infections acquired during pregnancy. The projected benefits from covering pregnant women by the HIV prevention programs is more substantial in communities in which the sexual risk during pregnancy is eleva
Brisson M, Laprise J-F, Drolet M, et al., 2013, Comparative cost-effectiveness of the quadrivalent and bivalent human papillomavirus vaccines: A transmission-dynamic modeling study, VACCINE, Vol: 31, Pages: 3863-3871, ISSN: 0264-410X
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- Citations: 42
Dimitrov D, Boily MC, Mâsse BR, et al., 2013, Impact of pill sharing on drug resistance due to a wide-scale oral prep intervention in generalized epidemics, Journal of AIDS and Clinical Research, Vol: 4
Background: The first antiretroviral drug (Truvada) to be used as a pre-exposure prophylaxis (PrEP) in preventing HIV transmission is about to be approved. Behavioral studies suggest that a portion of users may share anti-retroviral drugs with sex partners, family, or friends. Pill sharing will decrease PrEP efficacy and adherence level, and potentially create an environment favorable for the development of drug resistance. We aim to evaluate the potential impact of pill sharing on the PrEP effectiveness and on the rates of drug-resistance development in heterosexual populations. Methods: A transmission dynamic model was used to assess the population-level impact of oral PrEP. The fractions of new HIV infections prevented (CPF), drug resistance prevalence and the proportion of new infections in which drug-resistant HIV is transmitted (TDR) are evaluated over fixed time periods. The influence of different factors on CPF and TDR is studied through simulations, using epidemic parameters representative of the countries in Sub-Saharan Africa. Results: Without pill sharing, a 70% efficacious PrEP used consistently by 60% of uninfected individuals prevents 52.8% (95% CI 49.4%-56.4%) of all new HIV infections over ten years with drug-resistant HIV transmitted in 2.2% of the new infections. Absolute CPF may vary by 9% if up to 20% of the users share PrEP while the level of TDR and total resistance prevalence may increase by up to 6-fold due to pill sharing in some intervention scenarios. Conclusion: Pill sharing may increase the PrEP coverage level achieved in the population but it also affects the PrEP efficacy for the users who do not follow the prescribed schedule. More importantly, it creates a pool of untracked users who remain unreached by the effort to avoid sub-optimal PrEP usage by infected people. This increases substantially the potential risk of drug resistance in the population. © 2012 Dimitrov D, et al.
Shubber Z, Mishra S, Vesga JF, et al., 2013, THE HIV MODES OF TRANSMISSION MODEL: A SYSTEMATIC REVIEW OF ITS FINDINGS AND ADHERENCE TO GUIDELINES, SEXUALLY TRANSMITTED INFECTIONS, Vol: 89, Pages: A52-A52, ISSN: 1368-4973
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