bluuebunny/crossref_metadata_2025_split huggingface dataset:
O1-S06.02 Impact of pill sharing on drug-resistance and population-level effectiveness of a wide-scale oral PrEP intervention in resource-constrained settings
Authors: Dimitrov D , Boily M C , Mâsse B 
Published: July 2011

BackgroundIn 2010 two randomised trials suggested that pre-exposure prophylaxis (PrEP) products based on tenofovir, an antiretroviral drug either administered daily orally (oral PrEP) or applied topically (vaginal microbicides), significantly reduced HIV acquisition among adherent users. Behavioural studies also suggest that some PrEP users are compelled to share product with sex partners, family, or friends. Pill sharing (PS) decreases the adherence levels of the intended PrEP users and creates an uncontrolled environment for the development of drug-resistance. However PS effects on the expected population-level impact of PrEP interventions have never been assessed. Thus, we aim to evaluate the potential impact of PS on the PrEP effectiveness to prevent HIV transmission and the spread of drug-resistance in heterosexual populations in resource-constrained settings.MethodsA transmission dynamic model was used to assess the population-level impact of oral PrEP in a variety of intervention scenarios and high HIV prevalence settings. The cumulative fractions of new HIV infections prevented (CPF) and transmitted drug-resistance (TDR) are evaluated over fixed time periods under various epidemiological conditions. The influence of different factors (eg, acquisition rate, PrEP coverage, rates of resistance development) on CPF and TDR is studied through simulations, using parameter sets sampled from ranges representative of countries in Sub-Saharan Africa.ResultsWithout PS, a 70% effective oral PrEP intervention used by 60% of the population prevents about 52% (95% CI 49.6% to 53.8%) of all new HIV infections over 10 years (10 years CPF) if adherence is 100%. CPF increases by 7% in populations with 10% PS, assuming no efficacy reduction for those who share PrEP and reduces by 2% if the efficacy reduction for sharers (prescribers or untracked users) is 50%. However, the fraction of transmitted drug-resistance (TDR) increases 2- to 6-fold in all scenarios investigated. It depends on the success in preventing PrEP usage by HIV infected individuals.ConclusionsPS 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 dosing. It creates a pool of untracked users who do not receive counselling, remain hidden and unreached by the effort to avoid the PrEP usage by HIV infected individuals. This increases substantially the potential risk of drug-resistance development.
O1-S06.04 Modelling the effectiveness of combination prevention from a house-to-house HIV testing platform in KwaZulu Natal, South Africa
Authors: Alsallaq R , Baeten J , Hughes J , Abu-Raddad L , Celum C , Hallett T 
Published: July 2011

BackgroundAvailable HIV prevention interventions are partially efficacious, but might offer the best strategy to control HIV through synergistic combination and targeting. Home-based HIV testing and counselling (HBCT), conducted house-to-house, provides rapid population-level knowledge of HIV serostatus and a means to facilitate access to combined HIV prevention interventions: expedited referral to antiretroviral treatment (ART) for HIV+ persons, counselling for behaviour change, promotion of and referral for male circumcision and topical or oral PrEP for high-risk HIV- persons. Thus, massively conducted HBCT could serve as a platform for achieving high coverage of combination HIV prevention (HBCT-plus).MethodsWe used age-sex stratified mathematical model to investigate the impact of HBCT-plus-including population-wide HBCT, behaviour change counselling, initiation of ART for HIV+ persons meeting national guidelines, topical PrEP, and male circumcision-on population-level HIV incidence. Our model was calibrated to data for KwaZulu-Natal province of South Africa. Effects of HBCT and other components of the HBCT-plus intervention package were based on empirical data from African settings.ResultsWithout major intervention efforts in this province, the model projects HIV incidence to be approximately 2% through the year 2020. In contrast, with high-coverage of HBCT-plus intervention the model indicates that incidence could be reduced by approximately half, to 1%, under assumptions inAbstract O1-S06.04 table 1. Short and long term reductions in HIV incidence are mediated by short and long term behaviour changes following HBCT, respectively, and are manifested by repeated rounds of HBCT every 4 years. Longer-term impacts are supported by a reduction in infectiousness (due to timely initiation of ART as a result of earlier knowledge of serostatus because of HBCT) and susceptibility (due to circumcision) as well as associated ‘herd immunity’ effects.Abstract O1-S06.04 Table 1Uptake assumptions for combination HIV prevention (HBCT-plus)HBCT intervention HBCT coverage90%Linkage to ART intervention Uptake at CD4=35010% Uptake at CD4=20070% Uptake at CD4=5050%Circumcision intervention Uptake over 4 years50%ConclusionsMultiple evidence-based HIV preventive interventions combined and delivered through a platform of periodic HBCT could reduce population-level HIV incidence in South Africa by 50% within 4 years. Fast and slow acting components affecting infectiousness and susceptibility can make combination packages particularly strong. Multiple partially-effective tools for HIV prevention can be combined and if coverage is sufficient, substantial reductions in HIV incidence are potentially within reach.
O1-S06.05 Exploring the potential impact on HIV incidence of a reduction in concurrency in rural Uganda: a Modelling Study
Authors: McCreesh N , O'Brien K , Nsubuga R , Shafer L A , Bakker R , Seeley J , Richard W 
Published: July 2011

BackgroundThe empirical evidence for an association between sexual partnership concurrency and increased HIV acquisition or transmission is equivocal, and the likely impact of changes in the prevalence of concurrency on HIV incidence in countries with generalised HIV epidemics has not been explored. Despite this, a number of SSA counties have planned or implemented campaigns against concurrency. Evaluation of these campaigns is unlikely to provide strong evidence for the likely impact of changes in concurrency on HIV incidence as it will not be possible to separate the effects of a reduction in concurrency from the effects of a reduction in partnership incidence. This modelling study investigates the potential effect on HIV incidence of an intervention to reduce concurrency in rural Uganda, and in other sub-Saharan Africa populations with higher levels of concurrency.MethodsData on the demography, sexual behaviour, and HIV prevalence of a cohort in Masaka, Uganda were used to parameterise an individual-based HIV transmission model. The UNAIDS recommended definition of concurrency was used. Four scenarios with different prevalences of male and female concurrency were modelled. An intervention that reduced partnership concurrency by 50% between 2010 and 2020 (keeping overall partnership incidence constant) was introduced and the impact on HIV incidence in 2020 was calculated.Results9.6% (7.9%–11.4%) of men and 0.2% (0.0%–0.4%) of women reported concurrent sexual partnerships in rural Uganda in 2010. Preliminary results suggest that in the model scenario simulating this reported behaviour, the intervention reduces the incidence of HIV by 7.4% in men and 19.9% in women (Abstract O1-S06.05 figure 1, scenario 1a). If more female concurrency is simulated, the potential reductions of the intervention are greater (11.1%–14.8% in men and 21.6%–24.7% in women, Abstract O1-S06.05 figure 1, scenarios 2a and 3a). The potential reductions are also greater when a higher prevalence of male concurrency is simulated (9.7%–15.5% in men and 26.6%–29.6% in women, Abstract O1-S06.05 figure 1, scenarios 1b, 2b and 3b).Abstract O1-S06.05 Figure 1The impact of the intervention on HIV incidence in 2020.ConclusionsIn this setting, interventions against concurrency have the potential to reduce the HIV incidence and may have a higher impact on the incidence of HIV in women than in men. However a large simulated change in behaviour resulted in only a moderate decrease in HIV incidence. This study does not provide strong support for the prioritisation of concurrency as a target for behaviour change interventions.
O1-S07.02 Characteristics of women testing positive for rectal STIs using self-collected mailed specimens
Authors: Ladd J , Hsieh Y H , Barnes M , Agreda P , Quinn N , Whittle P , Jett-Goheen M , Hogan T , Gaydos C 
Published: July 2011

BackgroundThe websitehttp://www.iwantthekit.org/(IWTK) began offering self-administered rectal swab kits in addition to vaginal swab kits in January 2009 to test forChlamydia trachomatis,Neisseria gonorrhoeae, andTrichomonas vaginalis.MethodsSwab samples were collected at home by participants and sent by US mail and tested by NAAT (Gen-Probe) assays. Participants submitted separate questionnaires for the vaginal and rectal kits. Data were analysed by STATA, version 11.ResultsIn 1084 questionnaires from women submitting vaginal swabs to the IWTK program since 2009, 194 (17.9%) reported anal intercourse (AI) in the last 90 days. Of these women, only 113 (58.2%) also ordered and returned rectal kits for testing. An additional 95 kits were ordered and returned by women who did not report recent AI (82), did not return a vaginal swab (5), or did not answer the AI question on the vaginal questionnaire (8). From a total of 406 rectal kits ordered by women overall, 208 (51.2%) were returned; three had no consent form; thus, 205 were tested. Of those tested, 26 (12.7%) were positive for chlamydia, 5 (2.4%) were positive for gonorrhoea, and 13 (6.3%) were positive for trichomoniasis. Two of these samples were positive for both Chlamydia and gonorrhoea, two for both chlamydia and trichomonas, and one for all three STIs. The total number of women testing positive for any rectal STI was 38 (18.5%), and 35 of these women also received and returned vaginal swabs, 34 of which were tested. Of those tested, 24 (70.5%) were positive for at least one of the three STIs vaginally, indicating that women who tested positive for rectal STIs were at very high risk for vaginal STIs. Of the 38 women with rectal STIs, the median age was 22 yr. and the median age of first rectal sex was 20 yr. Questionnaires demonstrated 93.6% were single, 62.5% were Black, and 21.9% were White. Of the women with rectal STIs, 67.7% reported no symptoms, 12.0% reported no rectal partners in previous yr, 56.0% reported one partner, and 32% reported 2–4 partners. Only 16.0% reported having a new rectal partner in the last 3 months. Half (50.0%) reported never using condoms, 15.4% reported they always used condoms, 15.4% reported using condoms most of the time, and 19.2% reported using condoms some of the time.ConclusionsPublic health officials should be aware that AI and rectal STIs are not uncommon among sexually active women. Future STI screening programs should consider rectal infections.
O1-S07.05 Rare event: rectal specimen collection from males for chlamydial infection in the USA
Authors: Tao G , Hoover K , Body B , Nye M , Kent C 
Published: July 2011

BackgroundUS guidelines recommend annual Chlamydia screening of the rectum and urethra among men who have sex with men (MSM) with sexual exposure at these anatomic sites. Routine pharyngeal chlamydia screening is not recommended. About 6% of US males have a history of sex with men. The prevalence of rectal chlamydia has consistently been high among MSM with a history of receptive anal sex. One study indicated that up to 53% of chlamydial infections would be missed and not treated if only urethral testing was performed among MSM. We examined data from a large commercial laboratory corporation with a substantial share of the US market and testing available across all 50 states, that also offers rectal and pharyngeal testing with nucleic acid amplification tests (NAAT), to estimate the frequency and positivity of specimens collected from men by anatomic site for chlamydia testing.MethodsData for all Chlamydia testing methods was obtained by a large commercial laboratory between June 2008 and July 2010. The data set was then queried to obtain testing performed on males and analysed for anatomic site, test type, test result and age. Urethral and urine specimens were assumed to be testing for urethral infections.ResultsChlamydia testing was performed on 227 188 specimens from men: 98.2% urethral, 1.3% rectal, and 0.5% pharyngeal. The age distribution of those tested was: 2.4%<15 years, 15.0% 15–19 years, 15.7% 20–24 years, 15.6% 25–29 years, 12.5% 30–34 years, 10.8% 35–39 years, 10.0% 40–44 years, and 18.0% >44 years. Chlamydia positivity varied by anatomic site (8.7% rectal, 6.9% urethral, and 3.5% pharyngeal), and by age (2.5% <15 years, 13.2% 15–19 years, 12.5% 20–24 years, 7.7% 25–29 years, 5.3% 30–34 years, 3.9% 35–39 years, 3.1% 40–44 years, and 1.7% >44 years). Of 2918 rectal specimens, 17.8% were tested by culture and 75.5% by NAAT, compared to 93.5% of urethral specimens tested by NAAT.ConclusionsGiven the sexual practices of men in the US, it appears that only a small proportion of MSM are appropriately screened for rectal Chlamydia. Lack of FDA clearance for these specimen sources may contribute to the small proportion of MSM being screened for rectal Chlamydia. Interventions to increase rectal chlamydial testing among MSM are needed. Because data from this corporation represents a large proportion of testing in the US, it could be used to monitor changes in chlamydia testing practice among men in the future.
O1-S08.01 High HIV prevalence within a generalised epidemic; condom use, violence, and sexually transmitted infections among female sex workers in Dar es Salaam, Tanzania
Authors: Makyao N , Kangolle A , Gilly A , Somi G , Kazaura M , Kim E , Kibona M , Kamazima S 
Published: July 2011

BackgroundIn Tanzania, adult HIV prevalence is estimated at 5.8% and 9.3% in Dar es Salaam, well above the level of a generalised epidemic. Nonetheless, HIV infection and a constellation of associated factors are disproportionately borne by marginalised groups within the country. Female sex workers (FSW) are one such group; however, little is known about them in Tanzania.MethodRespondent-driven sampling was used to recruit self-identified FSWs aged 15+ years, living in Dar es Salaam, who reported exchanging sexual intercourse for money in the past month. FSWs were interviewed about their social circumstances, STI risk behaviours and tested for HIV, Hepatitis B, C and other STIs. Point estimates and 95% CI were adjusted for social network size and recruitment patterns using RDSAT.ResultsFrom April to August 2010, 537 FSWs were recruited. Their median age was 29 years (range 15–63). Two FSWs (0.6% 95% CI: 0% to 1.7%) were <10 years when first selling sex (median age 17 years). Condom use at last sex was 82.1% (95% CI: 77.0% to 87.0%), but consistent use varied by type of partner; always condoms use with steady partner was 29.9% (95% CI: 22.8% to 37.6%) and 65.1% (95% CI: 58.4% to 71.4%) with one time client. The major reason for FSWs not using condoms was partner objection (44.1%; 95% CI: 32.6% to 56.2%). The prevalence of STIs and viral hepatitis varied: HIV 30.2% (95% CI: 24.7% to 36.4%); Hepatitis B 5.6 % (95% CI: 3.7% to 8.3%); Hepatitis C 1.4% (95% CI: 0.3% to 3.1%), syphilis 2.1% (95% CI: 0.8% to 3.4%); Gonorrhoea 10% (95% CI: 6.9% to 14.4%), and Chlamydia 6.9% (95% CI: 3.2% to 11.9%). Many (292; 51.7%, 95% CI: 46% to 58%) FSWs had experienced physical violence in the past 12 months and 34.7% (95% CI: 28.7% to 40.6%) had been forced to have sex. Few FSWs were IDU themselves (1.4%; 95% CI: 0.3% to 2.9%), but 5.1% (95% CI: 2.3% to 7.7%) suspected regular clients, and 8.9% (95% CI: 7% to 12%) suspected one-time clients were IDU. These women had significantly higher prevalence of HIV (46.8%; 95% CI: 31.5% to 63.9% compared to 23.1% (95% CI: 16.4% to 29.3%) for FSWs who did not suspect any partner.ConclusionFSWs of Dar es Salaam have many-fold higher prevalence of HIV than the general population, with variable levels of other STIs. Their health situation calls for multifaceted services and structural interventions beyond HIV education and condom promotion. Preventive, care and treatment and personal level empowerment strategies are desperately needed among FSWs in Dar es Salaam, Tanzania.
O1-S08.02 Who are the women at risk of HIV infection in rural Zimbabwe and how many are there? Insights into their characteristics, locations, and behaviours
Authors: Elmes J , Nhongo K , Hallett T , White P , Mutsindiri R , Garnett G , Nyamukapa C , Gregson S 
Published: July 2011

BackgroundIn Zimbabwe's generalised epidemic, the relative importance of different risk groups to ongoing HIV transmission is unclear. We estimated population sizes and HIV prevalence of women involved in different levels of sex work activity in two socioeconomic locations (rural areas and commercial centres) in east Zimbabwe.MethodsThe baseline survey for a cohort study of 650 women at high risk of HIV infection (WR) was conducted in March 2010, using snowball and location-based methods to recruit women with any form of sexual exchange motivated by material reward including cash-per-act and informal credit-based arrangements. We restricted our analysis to a subset of WR who report receiving money for sex, excluding non-monetary transactions. WR were assigned to high, medium or low activity levels based on, among other factors, the frequency they report receiving money for sex and numbers of partners. CIs are based on Agresti-Coull 95% estimation and p values are for χ2estimation unless otherwise stated.ResultsWR were more common in commercial centres than in rural areas 11.1% (9.9% to 12.4%) vs 5.0% (4.3% to 5.8%). The pattern of sex work activity differed between locations (p=0.049) and mean number of sexual partners, over 2 weeks, in high, medium and low activity WR were 4.1, 1.9 and 1.3 respectively (ANOVA test for trend: p<0.001). High activity WR comprised 2.4% (1.9% to 3.1%) of women in commercial centres vs 0.55% (0.34% to 0.89%) in rural; medium level, 7.1% (6.2% to 8.2%) vs 3.9% (3.3% to 4.7%); and low level, 1.56% (1.13% to 2.13%) vs 0.50% (0.30% to 0.82%),Abstract O1-S08.02 figure 1. Overall, HIV prevalence in WR was higher in commercial centres than in rural areas: 46.5% (95% CI: 38.9% to 54.3%) vs 37.8% (28.4% to 48.1%) (p>0.1). Mean HIV prevalence among high level WR was consistent across socioeconomic strata: 50% (range: 35.8%–64.2%). Prevalence among medium level WR tended to be higher in business centres: 47.5% (38.1% to 57.2%) vs 35.2% (25.1% to 46.8%) in rural areas. In contrast, HIV prevalence in low level WR was higher in rural areas: 44.4% (18.8% to 73.4%) vs 36.4% (19.6% to 57.1%).Abstract O1-S08.02 Figure 1Relative size and HIV prevalence of the WR population in two socioeconomic locations in east Zimbabwe. Circle sizes are in proportion to the relative size of WR activity level; the inner ring represents low activity, the central ring high activity and the outer ring medium activity WR.ConclusionsSex worker populations may be larger than previously measured in general population surveys in rural Zimbabwe. Given that HIV prevalence among WR is threefold higher than in the general population and the underestimated size of the sex worker population, sex work may be an increasingly important driver of HIV transmission in declining generalised rural African epidemics.
O1-S08.03 Condom use during work time among female sex workers in Benin
Authors: Diabaté S , Chamberland A , Geraldo N , Zannou D M , Loembé M M , Anagonou S , Labbé A C , Tremblay C , Alary M 
Published: July 2011

BackgroundCondom use remains the cornerstone of HIV prevention in sub-Saharan Africa where HIV transmission is predominantly heterosexual. The aim of this study conducted in Cotonou, Benin, was to determine factors associated with unprotected sex among female sex workers (FSW), an important core group for the transmission of HIV and sexually transmitted infections (STI).MethodsWe have recruited and followed 396 FSW in a reference center for STI treatment. Condom use was assessed at enrolment and 6 months thereafter. FSW were asked how often they have used condoms with their clients during the last 7 days of work. During the study, FSW were encouraged to always use condoms with their clients. A generalised estimating equation model for binomial distribution with repeated measures was used to isolate factors independently associated with failure to use condoms during any sexual act.ResultsThe cohort comprised 1) 149 HIV-positive FSW, of which 52 were treated with antiretroviral therapy (ART) and 97 were not yet eligible for ART and 2) 247 HIV-negative subjects. Mean age (standard deviation; sd) and mean number of clients (sd) during the last 7 days of work were, respectively, 33.8 (9.3) years and 28.4 (26.1) clients. The majority of the FSW (55.3%) did not practice in brothels or equivalent set ups. At enrolment, 5.6% of the FSW reported that they have never used condoms during the last week of work. The proportion of FSW with full use of condoms during the last 7 days of work increased from 77.8% at enrolment to 90.6% 6 months after. First assessment of condom use (enrolment into the study) [RR 2.17; 95% CI 1.44% to 3.26%], not working in a brothel (RR 2.22; 95% CI 1.39% to 3.54%), having a relatively low monthly income (RR 1.63; 95% CI 1.04% to 2.57%) and older age (RR 1.50; 95% CI 1.03 to 2.21%) were independently associated with failure to always use condoms with the clients. Being HIV-infected or being treated with ART was not associated with the issue of interest. The reasons reported by the FSW for not using condoms during the last sexual act were dominated by the refusal of the client (46.0%).ConclusionAs suggested by our results, interventions promoting condom use during any commercial sexual act are fruitful and need to target women outside brothels, economically more vulnerable and older FSW as well as their clients.