bluuebunny/crossref_metadata_2025 huggingface dataset:
P1-S4.17 Interactive demonstration of a model to calculate costs and cost effectiveness of different strategies for chlamydia screening and partner notification
Authors: Turner K , Adams E , Grant A , Macleod J , Bell G , Clarke J , Horner P
Published: July 2011

Background

We have developed a model to calculate costs and cost effectiveness of different intervention strategies for chlamydia screening, which can be used by commissioners to evaluate and plan their local service provision. The model and an analysis of national data have been recently published in BMJ. Increasingly, financial constraints will mean that tools such as ours will be vital to provide value for money in healthcare.

Method

We will give a live demonstration of our spreadsheet model using the example from our recent study. We invite delegates to input their own data in real time to a laptop for comparison and testing against the national and international picture. We plan to promote this before the meeting.

Main outcome measures

Cost effectiveness of screening (as cost per individual tested, cost per positive diagnosis, total cost of screening, number screened, number infected, sex ratio of those tested and treated). We will show how to compare current programmes with a planned change eg, in screening coverage or partner notification efficacy.

Results

In 2008−2009 screening was estimated to cost £46.3 m and £506 per infection treated. The model results suggest that increasing male screening coverage from 8% to 24% (to match female coverage) would cost an extra £22.9 m and increase the cost per infection treated to £528. Increasing partner notification efficacy from 0.4 to 0.8 partners per index case would cost an extra £3.3 m and reduce the cost per infection diagnosed to £449.

Conclusions

The results are broadly representative of the national picture, but further evaluation of the cost effectiveness of partner notification and screening is urgently needed. We encourage practitioners who want to test this tool in their own setting to contact us (katy.turner@bristol.ac.uk).BMJ2011; 342:c725010.1136/bmj.c7250.
P1-S4.18 Using mathematical modelling to investigate the role of the hidden “population of men who have sex with men (MSM) on the HIV epidemic in Southern India”
Authors: Prudden H , Foss A , Mitchell K , Pickles M , Phillips A , Ramesh B M , Washington R , Alary M , Lowndes C , Vickerman P
Published: July 2011

Background

Biological and behavioural data for men who have sex with men (MSM) in Bangalore, Karnataka, India, have mainly been collected from sites where commercial sex is prevalent. Consequently, the survey data may fail to capture the behaviour of a larger lower-risk “hidden” MSM population. Mathematical modelling is used to explore the potential bias in the survey data and better quantify the characteristics of this hidden population.

Methods

A dynamic model of HIV transmission among MSM was developed and parameterised using detailed data* from high risk MSM in urban Bangalore. The MSM were categorised into three subgroups: Kothi and Hijra(KH): who mostly take the receptive role in anal sex, Panthis and Bisexuals(PB) who are predominantly insertive partners and Double Deckers(DD) who take both roles. Due to the sampling methods used, it was thought the MSM survey data were more representative of KH and DD than PB, although the extent of this bias is unknown. Therefore, no fitting constraint was applied to the PB HIV prevalence and instead the model was used to explore what PB HIV prevalence values are projected if the model was only fit to the 95% CIs of the prevalence data for KH and DD. One million randomly sampled model simulations were undertaken to find model fits.

Results

Abstract P1-S4.18 figure 1 shows that, although the model can produce HIV prevalence estimates consistent with the survey estimates, overall the model projections suggest a lower PB HIV prevalence is more consistent with the survey estimates for KH and DD. In addition, 80% of the model fits to the KH and DD HIV prevalence data had a sampled frequency of sex acts for PB in the lower half of the uncertainty interval suggesting PB's sexual activity may be lower than the median reported in the MSM survey. As expected, an inverse relationship occurs between PB population size and their level of sexual activity, with the median PB population size being 55 400 (2.7% of the total urban male population) and varying between 28 000 and 73 000 (1.5 to 3.9% of the total urban male population) for the IQR of the model fits Conclusions: Survey data imply MSM are a small, highly active group, many of whom regularly sell sex, have very high numbers of partners and typically take the receptive role. As demonstrated here, modelling can be used to provide insights into the likely HIV prevalence, population size and sexual activity of hidden “MSM not reached in surveys.”

Abstract P1-S4.18 Figure 1

Number and range of projected HIV prevalence estimates for the PB population (from the model fits to KH and DD data. *Integratedbiological and behavioural assessment (IBBA) 2009, collected within the monitoring and evaluation of Avahan, the India AIDS initiative.
P1-S4.19 Stochastic network models
Authors: Noël P A , Allard A , Hébert-Dufresne L , Marceau V , Dubé L J.
Published: July 2011

Background

We present a general modelling scheme particularly adapted for the epidemiology of sexually transmitted infections. Emphasis is placed on the complex interaction structure of the population and on the probabilistic nature of the dynamics.

Methods

We represent the interaction structure of the population with complex network models. Markov Stochastic Processes are used to consider the probabilistic time evolution of both the network structure and the epidemiological state of the population. Idealised epidemiological problems are considered: they are qualitatively inspired by real-world systems but no actual real-world data is fed to the models. All analytical results are systematically validated through Monte Carlo numerical simulations.

Results

By dedicating compartments to individuals with both similar epidemiological states and similar contact patterns, we observe great agreement between analytical results and Monte Carlo simulations see Abstract P1-S4.19 Figure 1. This is a special case of the general observation that compartmental models perform better when individuals within each compartment are very similar among themselves. Explicit examples are given for contact patterns changing through time as well as for the interactions of different infections in the same population.

Abstract P1-S4.19 Figure 1

Epidemiology on networks.

Conclusions

By specifying the structure of the population through its local features, we successfully model the probabilistic evolution of complex epidemiological systems. Infection stages and/or behavioural groups are considered the same way they are in “classical” compartmental models. The generality of the approach facilitates its application to a vast array of epidemiological phenomena.
P1-S1.17 HIV-1 molecular epidemiology in the Middle East and North Africa
Authors: Mumtaz G , Hilmi N , Akala F A , Semini I , Riedner G , Wilson D , Abu-Raddad L
Published: July 2011

Background

Human Immunodeficiency Virus Type I (HIV-1) is characterised by a high genetic variability. The distribution of HIV-1 subtypes in a population can help track transmission patterns and the evolution of the epidemic. The Middle East and North Africa (MENA) continues to be perceived as a region with limited HIV epidemiological data, but recent research indicates that nascent HIV epidemics appear to be emerging among high-risk groups including injecting drug users (IDUs), men who have sex with men (MSM), and female sex workers. The objective of this work was to review all evidence on HIV-1 subtype distribution in MENA where there remains several gaps in our understanding of the HIV epidemic.

Methods

A comprehensive systematic review of all HIV-1 molecular epidemiology data in MENA was undertaken. Sources of data included (1) PubMed using a strategy with both free text and MeSH headings, (2) country-level reports and database including governmental and non-governmental organisations publications, and (3) international organisations reports and databases.

Results

In several countries such as in Lebanon, Saudi Arabia, and Yemen, a very diverse distribution of HIV-1 subtypes was observed reflecting principally travel-related exogenous exposures. A trend of a dominant HIV-1 subtype was observed in few other settings and was often linked to HIV transmission within specific high-risk core groups such as subtype A and CRF35_AD among IDUs in Afghanistan, Iran, and Pakistan; and subtype C in heterosexual commercial sex networks in Djibouti and Somalia. Subtype B was predominant in Northern Algeria, Tunisia, and Morocco, but this appeared to reflect a mix of indigenous endemic transmission and exogenous exposures of West European and North American origin.

Conclusions

Multiple introductions of HIV-1 variants due to exogenous exposures of nationals seemed common to all MENA countries, as observed from the high diversity in subtypes or the high genetic divergence among any specific subtype even if predominant. This is in part a reflection of the high population mobility in MENA. In several countries though, epidemic-type clustering of specific subtypes suggests established or nascent HIV epidemics among classical core risk groups for HIV infection. With overall weak surveillance systems in MENA, molecular investigations could help identify the emergence of hidden epidemics among high-risk groups. HIV prevention efforts in MENA must be prioritised for these groups.
P1-S4.26 Duration, incidence and prevalence ofChlamydia trachomatisin women: estimation by multi-parameter synthesis
Authors: Price M , Ades A E , De Angelis D , Welton N , Macleod J , Soldan K , Turner K , Simms I , Horner P
Published: July 2011

Background

An understanding of the prevalence and incidence ofChlamydia trachomatis(CT) infection is needed to assess the potential value of screening. Typically, the estimation of incidence, prevalence and duration are seen as distinct exercises. Here we estimate them simultaneously from the available data subject to the well-known relationship prevalence = incidence times duration.

Methods

We re-examine studies of duration of asymptomatic CT, based on recent reviews, and propose a model. Information from a recent synthesis of UK prevalence studies, and data on infection and re-infection rates in UK clinic settings, are used to generate estimates of incidence of infection in the general population, taking account of the effect of duration of infection on observed incidence. We use Bayesian multi-parameter evidence synthesis to check the consistency of the evidence and to produce internally coherent estimates of duration, incidence and prevalence in women.

Results

The three sets of evidence sources that directly inform incidence, prevalence and duration respectively were consistent with each other. Our estimates are: duration of asymptomatic infection 1.25 years (1.04, 1.50), average incidence and prevalence in 16–44 year olds 2.2% (1.7, 2.9) per year and 2.1% (1.7, 2.6) respectively.

Conclusions

The apparently heterogeneous estimates of duration of asymptomatic CT in the literature are explained by the different study designs. Adapted appropriately, they agree with UK prevalence and incidence data.
P1-S4.27 Quality assurance of syphilis serological test in Guangdong, China, 2004–2009
Authors: Zheng H P , Wu X Z , Huang JinM
Published: July 2011

Background

Syphilis has made a major comeback in China, now representing the most common communicable disease in many cities and regions. A total of 327 433 cases of syphilis were reported in 2009, accounting for a sevenfold increase since 1999. Accurate treponemal and non-treponemal serological testing are critical to providing a correct diagnosis, but there are substantial variations in the quality of serological diagnostic tests and testing across different parts of China. Since 2003, the Guangdong Provincial STI Control Center in collaboration with the Bureau of Public Health has developed a program on STIs laboratory construction and quality assurance system. We report the proficiency of serological test of syphilis among the STIs laboratories in Guangdong Province in 2004–2009.

Methods

Proficiency panels consisting of five samples with syphilis positive and negative sera were prepared in the provincial laboratory and sent to STIs laboratories for non-treponemal and treponemal testing once a year. Participating laboratories were asked to report the type of test used and quantitative and qualitative results for each serum. Each quantitative result was compared to the geometric mean of all participants' results, and was considered correct if it was less than fourfold difference from the mean titre.

Results

The numbers of STIs laboratories in Guangdong which participated in the survey increased from 19 to 225 and a total of 13 203 sera were tested from 2004 to 2009. 98% laboratories used the “toluidine red unheated serum” (TRUST) as their non-treponemal test and all laboratories used the “Treponema pallidumparticle agglutination assay” (TPPA) as their treponemal test. The mean accuracies of non-treponemal tests among the laboratories evaluated increased significantly from 78.9% in 2004 to 97.7% in 2009 (χ2=17.11, p<0.01) for qualitative test results, and from 75.8% in 2004 to 90.8% in 2009 (χ2=8.09, p<0.01) for quantitative test results. Higher accuracies were observed with TPPA ranging from 93.5 to 100% (χ2=2.85, p>0.05) for qualitative test results and improved from 73.7% to 86.5% (χ2=4.7, p<0.05) for quantitative test results during this period. For non-treponemal testing, 4.1% (113/2754) of the results were found to be false negative and 2.3% (34/1456) were found to be false positive. For qualitative treponemal results, 6.5% (96/1470) and 1.9% (17/889) of treponemal results were found to be false-negative and false-positive respectively. For quantitative results, it was worth noting that in some cases, four to seven-titre deviations were observed for the same sera.

Conclusion

This province-wide STIs laboratory construction and quality assurance system has helped to improve the accuracies of serological syphilis testing over time. But there is still room for improvement to facilitate improved control of syphilis in China.
P1-S4.29 Synthesis of evidence on implementation research on point-of-care syphilis tests: a systematic review
Authors: Jafari Y , Johri M , Ako-Arrey D , Shivkumar S , Lambert G , Claessens C , Klein M , Cajas J , Peeling R , Pai N
Published: July 2011

Background

With the increase in global prevalence of syphilis, synthesis of evidence of point-of-care (POC) assays is warranted. While a clear methodology exists to meta-analyse diagnostic performance, a clear rubric that incorporates implementation research outcomes (IRO) relevant for policy making is lacking. Recently, Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group called for a shift to emphasis on patient-centred outcomes for making policy recommendations. However, a lack of clarity in defining, elucidating, and reporting of these outcomes prevents their utilisation in practice. Within this context, we reviewed global evidence on IROs for syphilis POC tests.

Method

We systematically searched nine electronic databases for the period of January 1980 to September 2010. Articles that addressed IRO regarding POC syphilis tests were reviewed and data extracted. A second reviewer independently reviewed a subset of the articles. Outcomes were synthesised into a narrative review.

Results

31 (48%) from 64 full text articles assessed were included in the narrative review. Twenty-four studies were cross-sectional, six were case-control, while one was a clustered randomised control trial (RCT). IROs were categorised into: Acceptability, Preference, Feasibility, Prevalence, Barriers and Challenges, and Economic Evaluations of POC tests. Three papers reported outcomes on acceptability, four on preference, ten on feasibility, seven on impact, six on prevalence, seven on barriers and challenges, and seven on economic evaluations. Overall, studies were concordant on findings of high acceptability and feasibility of POC tests as well as the testing strategy used. Preference was not well demonstrated in studies. Impact was particularly well demonstrated in antenatal clinic attendees by a clustered RCT. Barriers and challenges ranged from biotechnological limitations of the tests to lack of political will. Heterogeneous methodologies employed across studies to conduct economic evaluations made it difficult to draw conclusive statements.

Conclusions

Results were generally in agreement across studies, yet unsystematic methods of collecting and recording outcomes made it difficult to statistically combine outcomes. Weaknesses in the reporting of IROs limit our ability to form comprehensive context-specific policies. Further efforts in establishing a framework for conducting implementation research is required.
P1-S4.32 Recruiting via social networking sites for sexual health research (assessing chlamydia and HPV knowledge)
Authors: Garland S M , Wark J D , Tabrizi S N , Jayasinghe Y , Moore E , Fletcher A , Gunasekaran B , Ahmed N , Fenner Y
Published: July 2011

Background

Recruiting participants into population health studies has become increasingly challenging: traditional strategies have limitations including low participation rates and high costs. Social networking sites, commonly used for communication by young people, present an unique opportunity for innovative recruitment modalities.

Method

This is part of a larger feasibility study assessing use of Facebook to recruit subjects for a novel prospective health study, the Young Female Health Initiative (YFHI). Women aged 16 to 25 years, living in Victoria, Australia were eligible to participate. An advertisement was placed on Facebook between May—and October 2010 and was visible to a random sample of eligible women. Women clicking on the advertisement were redirected to our website (http://www.yfhi.org) and invited to provide their contact details. They were contacted by a researcher and asked to complete a survey at the YFHI study site, or to complete the questionnaire online. The survey contained demographic questions, plus sensitive questions about sexual history, experience and knowledge ofChlamydia trachomatis, human papillomavirus (HPV) and HPV vaccines.

Results

551 women responded to the advertisement (recruitment could be scaled up or down by changing the advertising frequency). We enrolled 426 respondents, of whom 278 completed the survey within the time available (50% at the study site, 50% online). Respondents' age and geographical distribution (urban, regional, rural) was representative of the target population; women over 18 years were 37% more likely to enrol and complete the survey than 16–17-year olds (p<0.05). Despite the sensitive nature of some questions, over 98% of participants found the survey not at all, or only slightly, embarrassing. Overall, 63% had heard of HPV: of these, 73% knew that HPV is sexually acquired and 94% knew that it causes cancer. 78% had heard of chlamydia: those who were sexually active were more likely to know of chlamydia than virgins (p<0.01), while 63% knew it could cause chronic pelvic pain, and 86% that it could cause infertility. This recruitment method also was cost-effective ($USD 20 per compliant participant).

Conclusions

Results demonstrate excellent potential for such information and communication technologies (ICT) to engage young women in health research, including those from regional and rural communities, and support the use of ICT in future population-based studies, including sexual health research.
P1-S4.33 Effectiveness of respondent driven sampling among undocumented Central American Immigrant Women in Houston, Texas, 2010
Authors: Montealegre J , Risser J , Selwyn B J , Sabin K
Published: July 2011

Background

Respondent driven sampling (RDS) is a social research method that uses participants’ social networks (SNs) to access members of hidden populations for which there is no sampling frame. RDS is widely used for HIV behavioural research among sex workers, drug users, and other hidden populations. However, it has had minimum application in migrant populations. We used RDS to conduct an HIV behavioural survey among undocumented Central American immigrant women in Houston, Texas (specifically, Guatemalan, Honduran, and El Salvadoran females, ages 18–50 years, residing in Houston without a valid US visa or residency papers). Here we describe the effectiveness of RDS to recruit members of this population.

Methods

Formative research indicated that social ties are mainly formed by country of origin, age, and number of years living in the USA. Measures of effectiveness were survey duration, participants' adoption of the recruitment system, SN density, homophily, and attainment of equilibrium. SN density is the average number of social ties per participant. Homophily is the likelihood that individuals recruit individuals like themselves; scores range from −1 to 1, where 1=100% within-group recruitment and 0=100% random recruitment. Equilibrium is the stable sample composition that indicates independence from initial non-randomly selected participants.

Results

Beginning with three initial participants, we recruited a sample of 230 immigrant women over 16 weeks. Participants adopted the recruitment system with reasonable ease (46% recruited ≥1 peers) and SNs were dense (mean SN size=20). Homophily (H) was moderate by country of origin (Guatemalans: H=0.52; El Salvadorans: H=0.42) and low by age and number of years in the USA (H≤0.25). Equilibrium was attained for all demographic and sexual behaviour characteristics.

Conclusions

This study is the first to evaluate RDS in a migrant population. SNs in this population were dense, allowing recruitment to be sustained. While recruitment was moderately influenced by country of origin, women did not affiliate exclusively with those like themselves. This sociometric diversity allowed the sample to attain an equilibrium composition independent of initial participants. Overall, RDS was easy to implement, attained a large sample in a relatively short period of time, and reached an otherwise hidden population. RDS is an effective method for recruiting undocumented Central American immigrant women for HIV behavioural surveys in Houston.
P1-S5.01 Heterosexual Anal Sex, Lubrication, HIV, and HSV-2 infection among women
Authors: Brown J , Hess K , Brown S , Murphy C , Waldman A , Hezareh M
Published: July 2011

Background

Anal intercourse (AI) is associated with increased HIV and STI risk. Anal douching and use of AI lubrication may increase susceptibility to infection and may influence results of trials of microbicides for HIV prevention through effects on the rectal environment and on adherence to investigational microbicidal products. We measured the frequency of heterosexual AI, anal practices and lubricant use and their association with HIV and HSV-2 infection among women.

Methods

Between October 2008 and June 2009, we recruited women age 18 years and older in Los Angeles. At the enrolment visit and at the 12-month visit, participants underwent a self-administered, web-based questionnaire covering demographic factors, sexual Behaviours, and anal practices. HSV-2 was diagnosed by IgG ELISA, and HIV was diagnosed by rapid ELISA with confirmation by Western blot. Here we report data collected during the enrolment visit.

Results

We enrolled 141 women (34% identified as White, 40% Black, 26% Hispanic; the median age was 33 years (IQR=25–44)). Overall, 71% reported ever having AI, and 8% reported AI as current means of contraception. Overall, 18% reported AI over the past month, and among these women, the median number of monthly AI acts was 2 (IQR=1–3), 50% reported unprotected AI, 8% reported anal douching, and 58% reported using lubricant during AI. Commercial lubricants (38%), saliva (23%), petroleum jelly (15%), and lotion (12%) were the most commonly reported lubricants. The prevalence of HIV was 27% and HSV-2 was 57%. In multivariable analysis, AI was associated with testing positive for HIV (aOR=7.8 (95% CI=1.6 to 37.6)) and HSV-2 infection (aOR=3.3 (95% CI=1.2 to 9.1)) controlling for age, race, and lifetime sexual partners.

Conclusion

AI is associated with HSV-2 and HIV infection, and anal douching and use of anal lubricating products not specifically designed for intercourse is common among women. The frequency and health effects of anal practices and lubricants warrant further study.
P1-S5.04 HSV-2 Prevalence and Incidence among Stable HIV-1 Discordant Couples in Nairobi, Kenya
Authors: Muiru A , Bosire R , Guthrie B , Choi R , Merkel M , Chohan B , Kiarie J , Lohman-Payne B , Farquhar C
Published: July 2011

Background

To describe HSV-2 prevalence, incidence and their correlates among stable HIV-1 discordant heterosexual couples enrolled in an HIV-1 prevention cohort study in Nairobi, Kenya.

Methods

Between 2007 and 2009, 469 HIV-1 discordant couples were recruited from VCT centers, and were followed up quarterly for up to 2 years. Clinical staff administered a questionnaire assessing socio-demographics, behaviour, and biological characteristics. HSV-2 status was assessed using Focus Herpe-Select2 HSV IgG ELISA. Correlates of HSV-2 infection at enrolment, and during follow-up were identified by logistic regression and Cox proportional hazards analysis respectively.

Results

Of the couples, 189 (40%) were HSV-2 concordant positive, 114 (24%) were HSV-2 discordant, and 85 (18%) were concordant negative. The incidence of HSV-2 infection was 8.7 cases/100 person-years. 19 (17%) individuals in an initially HSV-2 discordant partnership and 11 (13%) in an initially HSV-2 concordant negative partnership acquired HSV-2 during follow-up. Of these 11 individuals, 9(81%) were the HIV-1 positive index case in the HIV-1 discordant relationship. In a multivariate analysis, HSV-2 prevalence at baseline was significantly associated with female gender (OR 4.4; (95% CI 2.9 to 6.7)), having an HSV-2 positive partner (OR 7.6; (95% CI 5.1 to 11.2)), being HIV positive (OR 2.2; (95% CI 1.5 to 3.1)), increasing age (OR 1.08; (95% CI 1.05 to 1.1)), and older age at sexual debut was protective (OR 0.87; (95% CI 0.83 to 0.93)). HSV-2 incidence during follow-up was significantly associated with female gender (HR 3.5; (95% CI 1.6 to 8.0)), having an HSV-2 positive partner (HR 4.9; (95% CI, 2.0 to 9.9)), and history of any other STI (HR 2.6; (95% CI 1.3 to 5.8)).

Conclusions

This is the first large study to report the prevalence and incidence of HSV-2 among sexual partners who are in a stable HIV-1 discordant relationship. Female gender, a history of any other STI, and having an HSV-2 positive partner were associated with an increased risk of acquiring HSV-2. 11 individuals a majority of them with HIV acquired HSV-2 during follow-up despite being in HSV-2 concordant negative relationship at enrolment. The high incidence of HSV-2 in couples who were initially HSV-2 concordant negative or HSV-2 discordant highlights the dire need for continuing comprehensive STD prevention programs particularly among high risk population Sub-Saharan Africa.
P1-S5.05 The emergence of HIV pandemic: who lifted the lid of the African SIV-HIV Pot? A hypothesis
Authors: Lovenetski A
Published: July 2011

A series of studies established that HIV infection in humans originated from multiple episodes of zoonotic transmission of CD4 T cell-tropic lentiviruses infecting African monkey species—Simian Immunodeficiency Viruses (SIV). HIV-1 derives from the chimpanzee (Pan troglodytes)—SIVcpz, while HIV-2 derives from SIVsm, which naturally infects the Sooty mangabey (Cercocebus atys). Pan troglodytes is present across West Central Africa. Cercocebus atys have their natural habitat in West Africa (Guinea-Bissau to Cote d'Ivoire). Timing the emergence of HIV-1 in humans: four of the earliest known instances of HIV-1 infection are as follows: A plasma sample taken in 1959 from an adult male living in the Democratic Republic of the Congo. A lymph node sample taken in 1960 from an adult female, also from the Democratic Republic of the Congo. HIV-1 found in tissue samples from an American teenager who died in St. Louis in 1969. HIV-1 found in tissue samples from a Norwegian sailor who died around 1976. An 1998 analysis of the plasma sample dated 1959 suggested that HIV-1 was introduced into humans around the 1940s or the early 1950s. In 2000 the results of a new study suggested that HIV-1 infection occurred around 1931 in West Africa. However, a study in 2008 dated the origin of HIV to between 1884 and 1924. Timing the emergence of HIV-2 in human population: in 2003 molecular timing analysis of two subtypes of HIV-2 (A and B) and SIVsm samples led to conclusion that subtype A had passed into humans around 1940 and subtype B in 1945. The data evidence that Africa was the continent where the transfer of emerged HIV-1 and HIV-2 to humans first occurred. What caused the HIV epidemic to spread so suddenly from African pot in late 70s and early 80s? In this connection let's recall the largest successful worldwide medical intervention in human history—the WHO Smallpox Eradication Programme (1967–1977). Smallpox epidemics had inflicted mankind throughout history, and during 1967 some 10–15 million cases were occurring in 30 endemic countries. In WHO monograph Smallpox and Its Eradication “the chronology and precise timing of the Programme progress was well documented including Africa region: at the end of 1971 smallpox was endemic in only three African countries and was completely eradicated by 1977. Can there be a possible link between the HIV-1/HIV-2 pandemic emergence from West and Central Africa and smallpox eradication?. Smallpox was endemic for most of the countries of West and Central Africa where HIV's originated. Smallpox may be fatal for the most of the HIV-infected immunocompromised persons resulting in interruption of HIV spread. Thus smallpox could be considered as a natural barrier that limited prevalence of newly emerged HIV-1/HIV-2 in local human population. Smallpox eradication probably was the key factor which may contribute the widespread of HIV's in the population of West and Central Africa and the subsequent HIV pandemic emergence”.
P1-S5.06 Oral sex and risk of sexually transmitted infections
Authors: Flagg E , Weinstock H , Workowski K , Peterman T
Published: July 2011

Background

Oral sex is a common sexual practice in the United States; in 2002, almost 90% of sexually active adults ages 20–44 and over half of teens 15–19 years reported having had oral sex with an opposite sex partner. Oral sex is thought by some men who have sex with men to have lower risk for HIV acquisition, and is a prevalent practice in this population. However, the risk of acquiring a given sexually transmitted infection (STI) from oral sex may depend on a number of factors, including the specific STI, particular oral sex practice, prevalence of the STI in the population, and the number of oral sex acts performed. It is difficult to quantify the risk of getting an STI from a specific type of oral sex activity, or compare risks due to specific sex acts, because most people who have oral sex also have vaginal and/or anal sex.

Methods

In order to develop public health messages on oral sex and STI risk, we performed a review of the scientific literature to assess the state of current knowledge for risks of seven STIs (including HIV) and six oral sex practices: insertive and receptive fellatio, cunnilingus, and anilingus. Approximately 200 publications between 1979 and 2010 were reviewed; only 65 reported novel findings for one or more of these 42 potential associations.

Results

The clearest evidence of risk was found for syphilis (all oral sex practices), chlamydia (insertive and receptive fellatio; receptive anilingus), gonorrhoea (insertive and receptive fellatio), herpes (insertive fellatio; receptive cunnilingus), and HIV (receptive fellatio). For example, for pharyngeal gonorrhoea 4 of 4 studies reported association with receptive fellatio; 1 of 1 study found none for insertive anilingus. Other STI and oral sex associations were less well-studied, or have not been documented. No reports allow direct per-contact estimates, but some facilitate comparisons with non-oral types of sexual contact. A number of studies did not specify whether ejaculation or use of barrier protection was assessed.

Conclusions

All oral sex practices are associated with risk of transmission of one or more STIs; however the relations between specific oral sex practices and risk of infection are not well-characterised for several STIs. Despite this, it is important to formulate appropriate public health messages regarding oral sex and STI risk. Future studies should clearly distinguish between specific oral sex practices and consider these factors in sample size determination.
P1-S5.10 Acute genital ulceration in South African Men: importance of age and sexual risk behaviours
Authors: Leichliter J , Lewis D , Paz-Bailey G
Published: July 2011

Background

Herpes simplex virus (HSV) is the leading cause of genital ulcer disease (GUD) in Africa. Although some studies have examined the demographics and sexual behaviours of men with GUD, less is known about the differences that may exist between men with new sexually-acquired ulcers and men with other forms of GUD.

Methods

Men with GUD (n=615), who were 18 years and older, were recruited from several primary healthcare clinics in Gauteng Province, South Africa. Participants received syndromic management, were tested for ulcer aetiology and urethritis pathogens by PCR, and for HIV, syphilis and HSV-2 by serology. We used survey and STI test data to examine correlates of initial vs recurrent HSV and acute ulcer outcomes. Of men with HSV (n=451), initial HSV was defined as a HSV-positive ulcer specimen and HSV-negative serology. Recurrent herpes was defined as a positive HSV specimen and serology. For all men, the acute ulcer outcome compared men who had initial HSV or who hadTreponema pallidum,Haemophilus ducreyi, orChlamydia trachomatisL1–L3 detected in their ulcer specimens (termed “acute ulcers”) to men with GUD who did not have any of the four etiologies (termed “non-acute ulcers”). Correlates consisted of demographic characteristics and sexual behaviours often associated with STI.

Results

Among all men, 29% had an acute ulcer, and of those with HSV, 30% had initial HSV. As compared to men with a non-acute ulcer, men with an acute ulcer were younger (p<0.01), more likely to be single (p<0.05), less likely to always use condoms with regular partners (p=0.03), had more casual partners in the last 3 months (p=0.03) but had fewer lifetime partners (p=0.02). As compared to men with recurrent HSV, men with initial HSV were significantly more likely to be younger (p<0.01), have multiple regular partners (p=0.03), and report having sex in last week (p=0.04), but were less likely to report ever exchanging sex for money (p=0.01) and had fewer lifetime partners (p<0.01).

Conclusions

Findings suggest that young age and recent sexual behaviour were associated with initial HSV and acute ulcers in this group of men. These data emphasise the importance of targeting STI/HIV prevention programs in South Africa to young men engaging in high-risk sexual activities. To facilitate this, it is important to ensure that young men are equipped with the appropriate knowledge and skills to either avoid acquiring, or to seek early treatment for, STIs.
P1-S1.19 Herpes simplex virus type 2 infection—seroprevalence in Siberia
Authors: Khryanin A , Reshetnikov O , Kandrushina M
Published: July 2011

Background

Herpes simplex virus type 2 (HSV-2) is a common sexually transmitted infection worldwide, and its prevalence has increased significantly over the last 2 decades in many developed countries. The prevalence rates of HSV-2 infection differ between populations, however, HSV-2 seropositivity is uniformly higher in women than in men and increases with age.

Objectives

Aim of the present study was to evaluate the seroprevalence of HSV-2 infection among various population groups in Siberia, Russia.

Methods

A sample of 1014 persons aged 14–64 years (47% males) were randomly selected from the general population in urban Novosibirsk (predominantly Caucasians) and rural regions of Tyva and Altai Republic (predominantly persons of Asian origin). The study includes data obtained in 1994–2005. Sera were tested for IgG antibodies to HSV-2 infection with type-specific ELISA (VectoHSV-2 IgG, Vector-Best, Novosibirsk, Russia).

Results

The overall prevalence of HSV-2 positivity was 21% being higher in females (26.4%) compared to males (17.0%, p=0.01). Seroprevalence rates increased with age from 0% at 14–17 years to 22.8% at 55–64 years in males and from 1.8% at 14–17 years to 31.6% at 55–64 years in females. Neither difference was observed between urban and rural population, nor in surveyed persons of Caucasian and Asian origin. Ten-year trend showed a decrease in the frequency of HSV-2 detection equally in different populations by 20%. In conclusion, HSV-2 is common in Russia with the prevalence rates close to USA and Scandinavian countries. The sex and age distribution of the infection in Russia is similar to other populations. In Siberia, ethnicity and standard of living do not influence HSV-2 prevalence.
P1-S5.14 Risk factors associated with HIV acquisition: a comparative analysis of older and younger women who participated in the MDP301 trial in Johannesburg
Authors: Delany-Moretlwe S , Nanoo A , Nagpal A , Moultrie H , Delany S , Rees H
Published: July 2011

Background

Young women are known to be particularly at risk for HIV infection. Identifying characteristics associated with HIV-acquisition in younger and older women could assist with developing effective interventions which target the determinants of HIV.

Methods

The MDP301 study was an international, multi-centre, randomised controlled trial to assess the efficacy of 0.5% PRO2000/05 microbicide gel. 2508 HIV-negative women, ≥18 years, were enrolled in Soweto and Orange Farm and followed up for 12 months. Associations between baseline demographic, behavioural and clinical risk factors and HIV acquisition were assessed using univariate Poisson regression.

Results

Data on 2451 women were analysed. 110 seroconversions were observed over 2356.5 woman-years (wy). Overall, HIV incidence was 46.7/1000 wy (95% CI 38.7 to 56.3). Younger women (18–24 years) were more likely to acquire HIV (IRR1.4, 95% CI 1.0 to 2.0) than older women (≥25 years). Difficulty accessing money for medical treatment (IRR 1.5, 95% CI 0.06 to 2.0, p=0.019) and being HSV2 seropositive at baseline (IRR1.7, 95% CI 0.99 to 2.8, p=0.055) were associated with an increased risk of seroconversion in younger women. In older women, decreasing partner contribution to the household economy (IRR 1.3, 95% CI 1 to 1.7) andTrichomonas vaginalisinfection at enrolment (IRR 2.3, 95% CI 1.1 to 4.9) were associated with increased risk of HIV acquisition. Older women who reported condom use at last sex act had a greater risk of acquiring HIV (IRR 2.8, 95% CI 1.3 to 5.9), which could reflect high risk sexual behaviour in this group. Reporting multiple partners was associated with increased risk of HIV acquisition in both younger (2.6, 1.3 to 5.3) and older women (2.8, 1.3 to 6.1).

Conclusions

STIs remain an important marker of ongoing HIV risk. Interventions that address the economic context of women's HIV risk will be important to evaluate. Additional investigation using multivariate analysis may elucidate these findings further.
P1-S5.15 Contribution of condom breakage to the HIV epidemic among men who have sex with men in Karnataka, India
Authors: Pickles M , Vickerman P , Bradley J , Ramesh B M , Isac S , Washington R , Prudden H , Mitchell K , Alary M , Boily M C
Published: July 2011

Background

Condom promotion among female sex workers (FSWs) and men who have sex with men (MSM) is one of the key components of the Avahan HIV intervention currently underway in India. High rates of consistent condom use are reported across sites. However, condoms are only effective if they do not break or slip during intercourse, which occur frequently, especially in MSM.

Methods

We use a deterministic compartmental mathematical model of MSM divided into high and low risk, with average condom use increasing over time, to investigate how breakage influences the course of the epidemic. High-risk MSM (HRMSM) sell sex or have many casual partners, and typically have mostly receptive anal sex. Prior parameter ranges (including condom use) for the model are based on one round of cross-sectional behavioural and biological (IBBA) surveys of HRMSM from four districts in Karnataka state in 2008. In these surveys 16.7% (82/491) of MSM report condom breakage in the last sex act. Condom use increased to 93% by 2008, and was assumed to be constant afterwards. The prior ranges are sampled using Latin hypercube sampling. Model runs that agree with measured HRMSM HIV prevalence (12.7–18.9%) provide the posterior parameter set fitting the data, and are used to make predictions of HIV prevalence with and without condom breakage after the start of the intervention in 2004.

Results

Abstract P1-S5.15 figure 1 shows change in high/low risk prevalences with and without condom breakage. Even with high rates of condom breakage, HIV prevalence among MSM declines from 16.7% (95% CI 12.7 to 20.8%) in 2004 to 7.9% (5.9 to 9.8%) in HRMSM by 2015. Without condom breakage HIV prevalence declines faster, to 5.6% (4.2 to 6.9%) by 2015. Compared to no condom breakage, there will be 10.3% (10.7%) more cumulative infections with breakage in high-risk (low-risk) MSM from 2004 until 2015. The annual extra fraction of new infections due to condom breakage increases from 4.1% (4.3%), in 2004, to 158.9% (165.3%), in 2015 in high-risk (low-risk) MSM, although the absolute number of infections due to condom breakage decreases as the epidemic is declining and condom use increases.

Abstract P1-S5.15 Figure 1

HIV prevalence against time for high-risk MSM (upper curves)and low-risk MSM (lower curves). Shaded region shows 2.5–97.5 percentiles and IQR with breakage. The dashed lines show the 2.5, 97.5 percentiles and quartiles without condom breakage.

Conclusions

HIV prevalence is projected to decline in MSM in Karnataka, given high rates of reported condom use, even with frequent breakage. However, there will be a large fraction of extra infections due to condom breakage. HIV intervention programmes should examine reasons for high rates of breakage and take steps to address this.
P1-S5.19 Marriage dissolution and HIV prevalence in rural Zimbabwe 2003–2008
Authors: Schumacher C , Nyamukapa C , Garnett G , Gregson S
Published: July 2011

Background

Over the past decade, HIV prevalence in Zimbabwe has significantly declined, with recent research attributing this decline to wide-spread behaviour change such as reductions in extramarital sexual partnerships. Despite these reductions in risky sexual Behaviours, infections could still be transmitted from one marital union to another as divorced or widowed HIV-positive persons remarry.

Methods

Using information collected through face-to-face interviews in 2003–2005 AND 2006–2008, we compared HIV prevalence and basic demographics among women and their spouses (married, or in a long-term or cohabiting relationship for >12 months) in Manicaland, Zimbabwe. We used logistic regression to assess differences in marital history and basic demographics between HIV seronegative concordant couples, HIV serodiscordant couples and HIV seropositive concordant couples.

Results

In nearly one-third of the 2836 (27.8%) of marital unions interviewed, at least one member was infected with HIV (n=787); both members were HIV positive in 372 couples (13%). Of the 415 serodiscordant couples, 157 (5.5%) were serodiscordant female positive. Overall, compared to those in seronegative concordant (NC) partnerships, women in female-positive discordant (FP) or seropositive concordant (PC) partnerships were older (25–34 years vs 15–24; OR 1.7, 95% CI 1.17 to 2.47; OR 3.35, 2.52 to 4.45, respectively), more likely to been divorced (FP OR 4.19, 2.83 to 6.20; PC OR 4.12, 3.10 to 5.48), and more likely to have been widowed (FP OR 7.83, 3.65 to 16.76; PC OR 7.86, 4.30 to 14.36). Similar but weaker trends in divorce/widowhood were observed among men in male-positive discordant relationships compared to men in SN relationships. Women in FP and PC partnerships both were nearly three times as likely to report >1 lifetime sex partners than women in SN partnerships (FP OR 2.82, 2.02 to 3.92; PC OR 2.86, 2.27 to 3.59); mean lifetime sex partners reported by women in FP and PC partnerships was similar (FP: 2.11 lifetime partners; PC 2.06).

Conclusions

HIV prevalence is high among persons in long-term, stable partnerships, and strongly associated with one or both partners reporting a history of divorce or being widowed. In particular, widowed and divorced women may play an important role in ongoing HIV transmission dynamics. VCT services and other interventions that target couples should be promoted among divorced and widowed individuals.
P1-S5.20 Multi-level analysis of the predictors of HIV prevalence among pregnant women enrolled in sentinel surveillance in four Southern India states
Authors: Thamattoor U , Thomas T , Banandur P ,   R S, Duchesne T , Abdous B , Washington R , Ramesh B M , Moses S , Alary M
Published: July 2011

Background

The heterogeneity of HIV epidemic in the districts of four Southern states of India is reflected in HIV prevalence in pregnant women (ANC HIV prevalence) as well. Earlier studies have attempted to identify district level high risk population parameters that influenced ANC HIV prevalence. It is important to identify other district and individual level factors that influence ANC HIV prevalence to plan effective interventions.

Methods

The data from cross-sectional studies, known as integrated biological and behavioural assessments (IBBA), carried out between 2004 and 2007 among female sex workers (FSWs), their clients and men who have sex with men (MSM) in 24 districts were used to generate district-level variables concerning high-risk sub-population. The data on HIV sentinel surveillance in the ANC population (dependent variable) were obtained from the National AIDS Control Organization (NACO) for the same years. Other district level data were obtained from various governmental agencies and other reliable sources. Multilevel logistic regression analysis was used to identify individual and district-level factors associated with ANC HIV prevalence.

Results

The mean annual ANC HIV prevalence between 2004 to 2007 in the 24 districts considered ranged from 0.25 to 3.25%. In the multilevel model, individual level factors such as age ≥25 years [Adjusted OR (AOR): 1.49; 95% CI 1.27 to 1.76], being illiterate (AOR: 1.64; 95% CI 1.07 to 2.53) and being employed (AOR: 1.38; 95% CI 1.17 to 1.64) were significantly associated with high risk of being infected by HIV. HIV prevalence among FSWs at the district level, which was a significant high risk population parameter in the earlier studies, remained significant in the current study (AOR: 1.03; 95% CI 1.01 to 1.05). The only other district level factor which was considered in the final model was percentage of women who married below age of 18 years (AOR: 1.02; 95% CI 1.00 to 1.04).

Conclusion

HIV prevalence among FSWs is a key determinant of HIV prevalence among pregnant women in Southern India. Illiteracy of women and high prevalence of women marrying under 18 years at district level are both indicators of low socio economic status. Therefore in addition to targeted interventions for FSWs, awareness programs among individuals from lower socio economic status might help in reducing incidence of HIV in pregnant women.