Serological testing algorithm shows rising HIV incidence in a UK cohort of men who have sex with men: 10 years application

Ensuring equitable, inclusive and meaningful gender identity- and sexual orientation-related data collection in the healthcare sector: insights from a critical, pragmatic systematic review of the literature

In several countries, no gender identity- and sexual orientation-related data is routinely collected, if not for specific health or administrative/social purposes. Implementing and ensuring equitable and inclusive socio-demographic data collection is of paramount importance, given that the LGBTI community suffers from a disproportionate burden in terms of both communicable and non-communicable diseases. To the best of the authors' knowledge, there exists no systematic review addressing the methods that can be implemented in capturing gender identity- and sexual orientation-related data in the healthcare sector. A systematic literature review was conducted for filling in this gap of knowledge. Twenty-three articles were retained and analysed: two focussed on self-reported data, two on structured/semi-structured data, seven on text-mining, natural language processing, and other emerging artificial intelligence-based techniques, two on challenges in capturing sexual and gender-diverse populations, eight on the willingness to disclose gender identity and sexual orientation, and, finally, two on integrating structured and unstructured data. Our systematic literature review found that, despite the importance of collecting gender identity- and sexual orientation-related data and its increasing societal acceptance from the LGBTI community, several issues have to be addressed yet. Transgender, non-binary identities, and also intersex individuals remain often invisible and marginalized. In the last decades, there has been an increasing adoption of structured data. However, exploiting unstructured data seems to overperform in identifying LGBTI members, especially integrating structured and unstructured data. Self-declared/self-perceived/self-disclosed definitions, while being respectful of one's perception, may not completely be aligned with sexual behaviours and activities. Incorporating different levels of information (biological, socio-demographic, behavioural, and clinical) would enable overcoming this pitfall. A shift from a rigid/static nomenclature towards a more nuanced, dynamic, 'fuzzy' concept of a 'computable phenotype' has been proposed in the literature to capture the complexity of sexual identities and trajectories. On the other hand, excessive fragmentation has to be avoided considering that: (i) a full list of options including all gender identities and sexual orientations will never be available; (ii) these options should be easily understood by the general population, and (iii) these options should be consistent in such a way that can be compared among various studies and surveys. Only in this way, data collection can be clinically meaningful: that is to say, to impact clinical outcomes at the individual and population level, and to promote further research in the field.

Inferring population HIV incidence trends from surveillance data of recent HIV infection among HIV testing clients

BACKGROUND

Measuring recent HIV infections from routine surveillance systems could allow timely and granular monitoring of HIV incidence patterns. We evaluated the relationship of two recent infection indicators with alternative denominators to true incidence patterns.

METHODS

We used a mathematical model of HIV testing behaviours, calibrated to population-based surveys and HIV testing services programme data, to estimate the number of recent infections diagnosed annually from 2010 to 2019 in Côte d'Ivoire, Malawi, and Mozambique. We compared two different denominators to interpret recency data: those at risk of HIV acquisition (HIV-negative tests and recent infections) and all people testing HIV positive. Sex and age-specific longitudinal trends in both interpretations were then compared with modelled trends in HIV incidence, testing efforts and HIV positivity among HIV testing services clients.

RESULTS

Over 2010-2019, the annual proportion of the eligible population tested increased in all countries, while positivity decreased. The proportion of recent infections among those at risk of HIV acquisition decreased, similar to declines in HIV incidence among adults (≥15 years old). Conversely, the proportion of recent infections among HIV-positive tests increased. The female-to-male ratio of the proportion testing recent among those at risk was closer to 1 than the true incidence sex ratio.

CONCLUSION

The proportion of recent infections among those at risk of HIV acquisition is more indicative of HIV incidence than the proportion among HIV-positive tests. However, interpreting the observed patterns as surrogate measures for incidence patterns may still be confounded by different HIV testing rates between population groups or over time.

Epidemiological factors associated with recent HIV infection among newly-diagnosed cases in Singapore, 2013-2017

Background

Early diagnosis is crucial in securing optimal outcomes in the HIV care cascade. Recent HIV infection (RHI) serves as an indicator of early detection in the course of HIV infection. Surveillance of RHI is important in uncovering at-risk groups in which HIV transmission is ongoing. The study objectives are to estimate the proportion of RHI among persons newly-diagnosed in 2013–2017, and to elucidate epidemiological factors associated with RHI in Singapore.

Methods

As part of the National HIV Molecular Surveillance Programme, residual plasma samples of treatment-naïve HIV-1 positive individuals were tested using the biotinylated peptide-capture enzyme immunoassay with a cutoff of normalized optical density ≤ 0.8 for evidence of RHI. A recent infection testing algorithm was applied for the classification of RHI. We identified risk factors associated with RHI using logistic regression analyses.

Results

A total of 701 newly-diagnosed HIV-infected persons were included in the study. The median age at HIV diagnosis was 38 years (interquartile range, 28–51). The majority were men (94.2%), and sexual route was the predominant mode of HIV transmission (98.3%). Overall, 133/701 (19.0, 95% confidence interval [CI] 16.2–22.0%) were classified as RHI. The proportions of RHI in 2015 (31.1%) and 2017 (31.0%) were significantly higher than in 2014 (11.2%). A significantly higher proportion of men having sex with men (23.4, 95% CI 19.6–27.6%) had RHI compared with heterosexual men (11.1, 95% CI 7.6–15.9%). Independent factors associated with RHI were: age 15–24 years (adjusted odds ratio [aOR] 4.18, 95% CI 1.69–10.31) compared with ≥55 years; HIV diagnosis in 2015 (aOR 2.36, 95% CI 1.25–4.46) and 2017 (aOR 2.52, 95% CI 1.32–4.80) compared with 2013–2014; detection via voluntary testing (aOR 1.91, 95% CI 1.07–3.43) compared with medical care; and self-reported history of HIV test(s) prior to diagnosis (aOR 1.72, 95% CI 1.06–2.81).

Conclusion

Although there appears to be an increasing trend towards early diagnosis, persons with RHI remain a minority in Singapore. The strong associations observed between modifiable behaviors (voluntary testing and HIV testing history) and RHI highlight the importance of increasing the accessibility to HIV testing for at-risk groups.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10478-5.

HIV incidence among sexual health clinic attendees in England: First estimates for black African heterosexuals using a biomarker, 2009-2013

Introduction

The HIV epidemic in England is largely concentrated among heterosexuals who are predominately black African and men who have sex with men (MSM). We present for the first time trends in annual HIV incidence for adults attending sexual health clinics, where 80% of all HIV diagnoses are made.

Methods

We identified newly diagnosed incident HIV using a recent infection testing algorithm (RITA) consisting of a biomarker (AxSYM assay, modified to determine antibody avidity), epidemiological and clinical information. We estimated HIV incidence using the WHO RITA formula for cross-sectional studies, with HIV testing data from sexual health clinics as the denominator.

Results

From 2009 to 2013, each year, between 9,700 and 26,000 black African heterosexuals (of between 161,000 and 231,000 heterosexuals overall) were included in analyses. For the same period, annually between 19,000 and 55,000 MSM were included. Estimates of HIV incidence among black Africans increased slightly (although non-significantly) from 0.15% (95% C.I.0.05%-0.26%) in 2009 to 0.19% (95% C.I.0.04%-0.34%) in 2013 and was 4-5-fold higher than among all heterosexuals among which it remained stable between 0.03% (95% C.I.0.02%-0.05%) and 0.05% (95% C.I.0.03%-0.07%) over the period. Among MSM incidence was highest and increased (non-significantly) from 1.24% (95%C.I 0.96–1.52%) to 1.46% (95% C.I 1.23%-1.70%) after a peak of 1.52% (95%C.I 1.30%-1.75%) in 2012.

Conclusion

These are the first nationwide estimates for trends in HIV incidence among black African and heterosexual populations in England which show black Africans, alongside MSM, remain disproportionately at risk of infection. Although people attending sexual health clinics may not be representative of the general population, nearly half of black Africans and MSM had attended in the previous 5 years. Timely and accurate incidence estimates will be critical in monitoring the impact of the reconfiguration of sexual health services in England, and any prevention programmes such as pre-exposure prophylaxis.

Implications for a policy of initiating antiretroviral therapy in people diagnosed with human immunodeficiency virus: the CAPRA research programme

Background

More than 100,000 people in the UK are living with a human immunodeficiency virus (HIV) infection. There are currently estimated to be around 4000 people newly infected in the UK per year, mostly men who have sex with men (MSM). It has become increasingly clear that antiretroviral therapy (ART) used to treat people infected with HIV also has a profound effect on infectivity. At the initiation of the programme, it was the policy in the UK to initiate ART in people when their cluster of differentiation 4 (CD4) count was approaching 350/µl.

Objectives

To assess what would be the effectiveness and cost-effectiveness of a policy of immediate initiation of ART at diagnosis among MSM, taking into account the potential reductions in new infections.

Design

We calibrated an individual-based model of HIV transmission, progression and the effect of ART in MSM, informed by a series of studies on sexual behaviour in relation to ART use and the transmission risk in people with viral suppression on ART, and by surveillance data collected by Public Health England.

Setting, participants and interventions

The series of studies used to inform the model included (1) the Antiretrovirals, Sexual Transmission Risk and Attitudes (ASTRA) study, a cross-sectional self-administered questionnaire study of people diagnosed with HIV attending eight HIV outpatient clinics in the UK (2011–12); (2) the Cognitive Impairment in People with HIV in the European Region (CIPHER) study, a study of levels of neurocognitive impairment in HIV-positive ASTRA participants and people from HIV clinics in Rome, Copenhagen and Minsk; (3) the Attitudes to, and Understanding of, Risk of Acquisition of HIV (AURAH) study, a cross-sectional self-administered questionnaire study of individuals who have not been diagnosed as HIV-positive attending 20 genitourinary medicine clinics across the UK (2013–14); (4) a substudy of sexual behaviour among individuals enrolled in an open-label multicentre international randomised trial (from 2013) of immediate versus deferred ART (to CD4 cell counts of 350/µl) in people with CD4 cell counts of > 500/µl [the Strategic Timing of Antiretroviral Therapy (START) trial]; and (5) Partners of People on ART: a new Evaluation of the Risks (PARTNER), an observational multicentre longitudinal study of HIV serodifferent heterosexual and MSM couples, in which the HIV-positive partner is on ART (2010–14).

Main outcome measures

The main outcome measures were the clinical effectiveness and cost-effectiveness of a policy of immediate initiation of ART at diagnosis.

Results

Based on data from studies (i)–(v), we estimated from our modelling work that increases in condomless sex (CLS) among MSM as a whole may explain the increase in HIV infection incidence in MSM epidemics over a time when ART coverage and viral suppression increased, demonstrating the limiting effects of non-condom use on the HIV epidemic among MSM. Accordingly, an increase in the overall proportion of MSM living with HIV who are virally suppressed on ART from the current level of < 60% to 90% without increases in CLS was required to achieve a reduction in the incidence of HIV among MSM to < 1 per 1000 person-years. The incremental cost-effectiveness ratio associated with the fourfold increase in levels of HIV testing and ART at diagnosis required to provide this increase from < 60% to 90% was £20,000 if we assumed continuation of current ART prices. However, this value falls to £3500 if we assume that ART prices will fall to 20% of their current cost as a result of the introduction of generic drugs. Therefore, our evaluation suggests that ART initiation at diagnosis is likely to be highly cost-effective in MSM at a population level, particularly accounting for future lower ART costs as generic drugs are used. The impact will be much greater if levels of HIV testing can be enhanced.

Limitations

It was necessary to make some assumptions beyond the available data in order to extrapolate cost-effectiveness through modelling.

Conclusions

Our findings suggest that ART initiation at diagnosis is likely to be cost-effective in MSM. Of note, after this programme of work was completed, results from the main START trial demonstrated benefit in ART initiation even in people with CD4 cell counts of > 500/µl, supporting ART initiation in people diagnosed with a HIV infection.

Future work

There is a need for future research into the means of increasing the frequency with which MSM test for HIV.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

HIV incidence in an open national cohort of men who have sex with men attending sexually transmitted infection clinics in England

OBJECTIVES

The aim of the study was to determine HIV incidence among men who have sex with men (MSM) who repeat test for HIV at sexually transmitted infection (STI) clinics in England, and identify associated factors.

METHODS

Annual HIV incidence and 95% confidence interval (CI) were calculated for a national cohort of MSM who tested HIV negative at any STI clinic in England in 2012 and had a follow-up test within 1 year using routinely collected data. Cox regression analyses were performed to identify predictors of HIV acquisition and population attributable risk for HIV infection was calculated for predictors.

RESULTS

In 2012, 85 500 MSM not known to be HIV positive attended any STI clinic in England, and 31% tested for HIV at least twice within 1 year at the same clinic. HIV incidence was 2.0 per 100 person-years (PY; 95% CI 1.8-2.2) among repeat testers. Incidence was higher among MSM of black ethnicity (3.2 per 100 PY) and those with a bacterial STI diagnosis at the initial attendance (3.2 per 100 PY). MSM with a previous syphilis or gonorrhoea infection were at significantly greater risk of acquiring HIV in the subsequent year [adjusted hazard ratio 4.1 (95% CI 2.0-8.3) and 2.1 (95% CI 1.4-3.2), respectively]. The predictors accounted for 37% of HIV infections.

CONCLUSIONS

Annual HIV incidence among MSM attending STI clinics in England is high. Previous STIs were predictors of HIV acquisition but only accounted for one in five infections. More discriminatory behavioural predictors of HIV acquisition could provide better triaging of HIV prevention services for MSM attending STI clinics.

Perceptions of Human Papillomavirus (HPV) infection and acceptability of HPV vaccine among men attending a sexual health clinic differ according to sexual orientation

Our aim was to gain a better understanding of the knowledge about Human Papillomavirus (HPV) infection and attitudes toward the HPV vaccine among men at risk for sexually transmitted infections (STI). A self-administered questionnaire was completed by attendees of the largest STI Center in Rome, Italy, from April to June 2013. Determinants of vaccine acceptability were investigated using a Structured Equation Model. A total of 423 males participated in the survey: 296 (70.0%) men who have sex with men (MSM) and 127 (30.0%) men who have sex with women (MSW). Only one half of the participants knew that HPV is the cause of genital warts (56.9% of MSM vs. 49.5% of MSW, p=0.28). Even less were aware that HPV causes cancer in men (37.2% vs. 27.3%, p=0.08). MSW were more likely to indicate HPV as a cause of cervical cancer (80.8% vs. 69.3%, p=0.03) and to have heard about the vaccine (58.3 vs. 43.6%, p=0.01). Moreover, 72.1% of MSM and 70.3% of MSW were willing to be vaccinated. A rise of one-unit in the HPV awareness score increased the OR of vaccine acceptability among MSM by 25% (OR 1.25, 95%CI: 1.05-1.49; p=0.013). Differently, only attitudes had a relevant effect on willingness to be vaccinated among MSW (OR 3.32, 95%CI: 1.53-7.17; p=0.002). Efforts should be made to maximize awareness of HPV, especially as a causative agent of genital warts and male cancers, and to reinforce positive attitudes toward vaccination among men visiting STI centers.

Potential impact on HIV incidence of higher HIV testing rates and earlier antiretroviral therapy initiation in MSM

BACKGROUND

Increased rates of testing, with early antiretroviral therapy (ART) initiation, represent a key potential HIV-prevention approach. Currently, in MSM in the United Kingdom, it is estimated that 36% are diagnosed by 1 year from infection, and the ART initiation threshold is at CD4 cell count 350/μl. We investigated what would be required to reduce HIV incidence in MSM to below 1 per 1000 person-years (i.e. <535 new infections per year) by 2030, and whether this is likely to be cost-effective.

METHODS

A dynamic, individual-based simulation model was calibrated to multiple data sources on HIV in MSM in the United Kingdom. Outcomes were projected according to future alternative HIV testing and ART initiation scenarios to 2030, considering also potential changes in levels of condomless sex.

RESULTS

For ART use to result in an incidence of close to 1/1000 person-years requires the proportion of all HIV-positive MSM with viral suppression to increase from below 60% currently to 90%, assuming no rise in levels of condomless sex. Substantial increases in HIV testing, such that over 90% of men are diagnosed within a year of infection, would increase the proportion of HIV-positive men with viral suppression to 80%, and it would be 90%, if ART is initiated at diagnosis. The scenarios required for such a policy to be cost-effective are presented.

CONCLUSION

This analysis provides targets for the proportion of all HIV-positive MSM with viral suppression required to achieve substantial reductions in HIV incidence.

Recent Transmission Clustering of HIV-1 C and CRF17_BF Strains Characterized by NNRTI-Related Mutations among Newly Diagnosed Men in Central Italy

BACKGROUND

Increased evidence of relevant HIV-1 epidemic transmission in European countries is being reported, with an increased circulation of non-B-subtypes. Here, we present two recent HIV-1 non-B transmission clusters characterized by NNRTI-related amino-acidic mutations among newly diagnosed HIV-1 infected men, living in Rome (Central-Italy).

METHODS

Pol and V3 sequences were available at the time of diagnosis for all individuals. Maximum-Likelihood and Bayesian phylogenetic-trees with bootstrap and Bayesian-probability supports defined transmission-clusters. HIV-1 drug-resistance and V3-tropism were also evaluated.

RESULTS

Among 534 new HIV-1 non-B cases, diagnosed from 2011 to 2014, in Central-Italy, 35 carried virus gathering in two distinct clusters, including 27 HIV-1 C and 8 CRF17_BF subtypes, respectively. Both clusters were centralized in Rome, and their origin was estimated to have been after 2007. All individuals within both clusters were males and 37.1% of them had been recently-infected. While C-cluster was entirely composed by Italian men-who-have-sex-with-men, with a median-age of 34 years (IQR:30-39), individuals in CRF17_BF-cluster were older, with a median-age of 51 years (IQR:48-59) and almost all reported sexual-contacts with men and women. All carried R5-tropic viruses, with evidence of atypical or resistance amino-acidic mutations related to NNRTI-drugs (K103Q in C-cluster, and K101E+E138K in CRF17_BF-cluster).

CONCLUSIONS

These two epidemiological clusters provided evidence of a strong and recent circulation of C and CRF17_BF strains in central Italy, characterized by NNRTI-related mutations among men engaging in high-risk behaviours. These findings underline the role of molecular epidemiology in identifying groups at increased risk of HIV-1 transmission, and in enhancing additional prevention efforts.

Continuous increase in HIV-1 incidence after the year 2000 among men who have sex with men in Rome: insights from a 25-year retrospective cohort study

To assess trends in HIV-1 incidence and risk factors for seroconversion among men who have sex with men (MSM) resident in Rome, Italy, a retrospective longitudinal cohort study was conducted over 25 years. Incidence rates and trends were modelled using Poisson regression and risk factors were assessed by multivariate Cox models. Of 1,862 HIV-1-negative individuals, 347 seroconverted during follow-up. HIV-1 incidence rates increased from 5.2/100 persons/year (p/y) in 1986 (95% confidence interval (CI): 2.3–11.5) to 9.2/00 p/y in 1992 (95% CI: 6.4–13.0), decreased to 1.3/100 p/y in 2001 and increased until 2009 (11.7/100 p/y; 95% CI: 7.4–18.6). The risk of HIV-1 seroconversion increased during the study period in younger MSM (incidence rate ratio (IRR) = 17.18; 95% CI: 9.74–30.32 in 16–32 year-olds and IRR = 5.09; 95% CI: 2.92–8.87 in 33–41 year-olds) and in those who acquired syphilis (IRR = 7.71; 95% CI: 5.00–11.88). In contrast, the risk of seroconversion decreased among highly educated MSM (IRR = 0.54; 95% CI: 0.35–0.82) and those without Italian citizenship (IRR = 0.45; 95% CI: 0.28–0.71). The HIV epidemic in MSM living in Rome continues to expand. Targeted prevention programmes against sexually transmitted infections to enhance knowledge transfer and behavioural skills are urgently required.

Recent infection testing algorithm (RITA) applied to new HIV diagnoses in England, Wales and Northern Ireland, 2009 to 2011

In 2009, Public Health England (PHE) introduced the routine application of a recent infection testing algorithm (RITA) to new HIV diagnoses, where a positive RITA result indicates likely acquisition of infection in the previous six months. Laboratories submit serum specimens to PHE for testing using the HIV 1/2gO AxSYM assay modified for the determination of HIV antibody avidity. Results are classified according to avidity index and data on CD₄ count, antiretroviral treatment and the presence of an AIDS-defining illness. Between 2009 and 2011, 38.4% (6,966/18,134) of new HIV diagnoses in England, Wales and Northern Ireland were tested. Demographic characteristics of those tested were similar to all persons with diagnosed HIV. Overall, recent infection was 14.7% (1,022/6,966) and higher among men who have sex with men (MSM) (22.3%, 720/3,223) compared with heterosexual men and women (7.8%, 247/3,164). Higher proportions were among persons aged 15-24 years compared with those ≥50 years (MSM 31.2% (139/445) vs 13.6% (42/308); heterosexual men and women 17.3% (43/249) vs 6.2% (31/501)). Among heterosexual men and women, black Africans were least likely to have recent infection compared with whites (4.8%, 90/1,892 vs 13.3%, 97/728; adjusted odds ratio: 0.6; 95% CI: 0.4-0.9). Our results indicate evidence of ongoing HIV transmission during the study period, particularly among MSM.

Antiretroviral therapy for prevention of HIV transmission: implications for Europe

The aim of this review is to summarise the evidence on the population-level effect of antiretroviral therapy (ART) in preventing HIV infections, and to discuss potential implications in the European context of recommending starting ART when the CD4 count is above 350 cells/mm3. The ability of ART to reduce the risk of HIV transmission has been reported in observational studies and in a randomised controlled trial (HPTN 052), in which ART initiation reduced HIV transmission by 96% within serodiscordant couples. As yet, there is no direct evidence for such an effect among men having sex with men or people who inject drugs. HPTN 052 led international organisations to develop recommendations with a higher CD4 threshold for ART initiation. However, there remains a lack of strong evidence of clinical benefit for HIV-positive individuals starting ART with CD4 count above 350 cells/mm3. The main goal of ART provision should be to increase ART coverage for all those in need, based on the current guidelines, and the offer of ART to those who wish to reduce infectivity; increased HIV testing is therefore a key requirement. Other proven prevention means such as condom use and harm reduction for people who inject drugs remain critical.

Circumcision among men who have sex with men in London, United Kingdom: an unlikely strategy for HIV prevention

OBJECTIVES

To explore attitudes toward circumcision among men who have sex with men (MSM) in London and the feasibility of conducting research into circumcision and HIV prevention in this population.

METHODS

A convenience sample of MSM visiting central London gyms completed a confidential, self-administered questionnaire between May and June 2008. Information was collected on participants' demographic characteristics, self-reported HIV status, sexual behavior, circumcision status, attitudes toward circumcision, and willingness to participate in research on circumcision and HIV prevention.

RESULTS

Of 653 MSM, 29.0% reported that they were circumcised. Overall, HIV prevalence was 23.3%; this did not differ significantly between circumcised and uncircumcised men (18.6% vs. 25.2%, respectively; adjusted odds ratio 0.79, 95% confidence interval: 0.50-1.26). A similar proportion of circumcised and uncircumcised men reported unprotected anal intercourse in the previous 3 months (38.8% vs. 36.7%, adjusted odds ratio 1.06, 95% confidence interval: 0.72-1.55). Uncircumcised men were less likely to think that there were benefits of circumcision than circumcised men (31.2% vs. 65.4, P < 0.001). Only 10.3% of uncircumcised men said that they would be willing to participate in research on circumcision as an HIV prevention strategy.

CONCLUSIONS

Most uncircumcised MSM in this London survey were unwilling to participate in research on circumcision and HIV prevention. Only a minority of uncircumcised men thought that there were benefits of circumcision. It is unlikely that circumcision would be a feasible strategy for HIV prevention among MSM in London.

High percentage of recent HIV infection among HIV-positive individuals newly diagnosed at voluntary counseling and testing sites in Poland

To gain insight into HIV transmission we estimated the proportion of those recently infected. We examined data from HIV-positive patients and a random 10% sample of HIV-negative patients tested at Voluntary Counseling and Testing sites in Poland in 2006. Archived samples from positive patients were tested by three assays to differentiate recent from long-standing infection. Using logistic regression, we examined the association of recent infection (at least one assay) with age, sex, HIV exposure category, and the interval between self-reported HIV exposure and previous HIV test. Of 13,511 tests, 154 (1.1%) were HIV positive, representing 19.7% (n=783) of new diagnoses in Poland in 2006. Demographic and behavioral data were linked for 95, of whom 45 (47%) were recently infected and 1,001 were HIV negative. New diagnoses were more likely to be injectors (17% vs. 2%), men who have sex with men (MSM) (37% vs. 12%), and less frequent condom users (7.8% vs. 14% always) compared to HIV negatives. The median number of partners during the past 12 months was one and two among positives and negatives, but was higher among MSM-four and three, respectively. Ever injectors were less likely to be recently infected (adjusted OR=0.15, 95%CI=0.03-0.73). Having two or more sexual partners in the past 12 months was an independent predictor of recent infection (4.01, 1.4-11.49). We found no evidence that age or sex predicted recent infection. These data reinforce health education campaigns for safe sex messages, especially among MSM. They also suggest, albeit based on a subset of new diagnoses, that interventions should not be limited to selected age/sex groups.

Towards estimation of HIV-1 date of infection: a time-continuous IgG-model shows that seroconversion does not occur at the midpoint between negative and positive tests

Estimating date of infection for HIV-1-infected patients is vital for disease tracking and informed public health decisions, but is difficult to obtain because most patients have an established infection of unknown duration at diagnosis. Previous studies have used HIV-1-specific immunoglobulin G (IgG) levels as measured by the IgG capture BED enzyme immunoassay (BED assay) to indicate if a patient was infected recently, but a time-continuous model has not been available. Therefore, we developed a logistic model of IgG production over time. We used previously published metadata from 792 patients for whom the HIV-1-specific IgG levels had been longitudinally measured using the BED assay. To account for patient variability, we used mixed effects modeling to estimate general population parameters. The typical patient IgG production rate was estimated at r = 6.72[approximate 95% CI 6.17,7.33]×10⁻³ OD-n units day⁻¹, and the carrying capacity at K = 1.84[1.75,1.95] OD-n units, predicting how recently patients seroconverted in the interval ^∧t = (31,711) days. Final model selection and validation was performed on new BED data from a population of 819 Swedish HIV-1 patients diagnosed in 2002–2010. On an appropriate subset of 350 patients, the best model parameterization had an accuracy of 94% finding a realistic seroconversion date. We found that seroconversion on average is at the midpoint between last negative and first positive HIV-1 test for patients diagnosed in prospective/cohort studies such as those included in the training dataset. In contrast, seroconversion is strongly skewed towards the first positive sample for patients identified by regular public health diagnostic testing as illustrated in the validation dataset. Our model opens the door to more accurate estimates of date of infection for HIV-1 patients, which may facilitate a better understanding of HIV-1 epidemiology on a population level and individualized prevention, such as guidance during contact tracing.

Increased HIV incidence in men who have sex with men despite high levels of ART-induced viral suppression: analysis of an extensively documented epidemic

BACKGROUND

There is interest in expanding ART to prevent HIV transmission, but in the group with the highest levels of ART use, men-who-have-sex-with-men (MSM), numbers of new infections diagnosed each year have not decreased as ARTcoverage has increased for reasons which remain unclear.

METHODS

We analysed data on the HIV-epidemic in MSM in the UK from a range of sources using an individual-based simulation model. Model runs using parameter sets found to result in good model fit were used to infer changes in HIV-incidence and risk behaviour.

RESULTS

HIV-incidence has increased (estimated mean incidence 0.30/100 person-years 1990-1997, 0.45/100 py 1998-2010), associated with a modest (26%) rise in condomless sex. We also explored counter-factual scenarios: had ART not been introduced, but the rise in condomless sex had still occurred, then incidence 2006-2010 was 68% higher; a policy of ART initiation in all diagnosed with HIV from 2001 resulted in 32% lower incidence; had levels of HIV testing been higher (68% tested/year instead of 25%) incidence was 25% lower; a combination of higher testing and ART at diagnosis resulted in 62% lower incidence; cessation of all condom use in 2000 resulted in a 424% increase in incidence. In 2010, we estimate that undiagnosed men, the majority in primary infection, accounted for 82% of new infections.

CONCLUSION

A rise in HIV-incidence has occurred in MSM in the UK despite an only modest increase in levels of condomless sex and high coverage of ART. ART has almost certainly exerted a limiting effect on incidence. Much higher rates of HIV testing combined with initiation of ART at diagnosis would be likely to lead to substantial reductions in HIV incidence. Increased condom use should be promoted to avoid the erosion of the benefits of ART and to prevent other serious sexually transmitted infections.

Missed opportunities for identifying primary HIV within genitourinary medical/HIV services

To assess the ability of three genitourinary medical centres to clinically identify primary HIV infection (PHI). Cases of recently acquired HIV infection, identified using the Health Protection Agency (HPA) avidity assay on all HIV diagnoses from January to August 2009, were investigated by case-note review. Sixty-four individuals were identified as PHI using the HPA avidity assay. Of 64 individuals, 31 (48%) were identified clinically. Imperial College identified 8/26 (31%), Guys and St Thomas' 15/27 (56%) and Brighton 8/11 (73%). Clinical suspicion of PHI was associated with reported unprotected anal intercourse (P = 0.017), seroconversion symptoms (P = 0.0004), a negative HIV test within six months (P = 0.024) and avidity assay result availability (P = 0.0169). Seventy percent of PHI cases missed had a documented risk factor. Thirty-five percent of those clinically identified with PHI were documented as informed of the associated enhanced infectivity. Suspicion of PHI was low despite documented risk factors and recent HIV-negative antibody tests. Counselling to prevent onward transmission was suboptimal.

Behavioral surveillance study: sexual risk taking behaviour in UK HIV outpatient attendees

This study aimed to determine demographic, behavioural and self-report disease/treatment variables among HIV-infected individuals (n = 666) that predict unprotected intercourse with a partner of unknown/discordant status. Sexual risk behaviour was reported by 12.8%. In multivariable analysis, risk was more likely to be reported by gay men compared to women or heterosexual men, and for those with higher psychological symptom burden. Psychological symptoms should be assessed and managed in the HIV outpatient setting to ensure integrated care that enhances prevention.

The Recent Infection Testing Algorithm (RITA) in clinical practice: a survey of HIV clinicians in England and Northern Ireland

OBJECTIVES

In order to estimate HIV incidence among high-risk groups, in January 2009 the Health Protection Agency introduced the Recent Infection Testing Algorithm (RITA) in England and Northern Ireland (E&NI), currently the only regions to inform patients of RITA results. This survey of HIV specialists aimed to investigate the role of RITA in patient management and explore clinicians' views on its role in clinical practice and during partner notification.

METHODS

An online questionnaire was distributed to HIV specialists via the British HIV Association membership email list in February 2011.

RESULTS

Forty-two HIV specialists from 32 HIV centres responded to the survey among 90 centres enrolled in the programme (response rate 36%). Testing for recent infection was considered standard of care by 83% of respondents, 80% felt confident in interpreting results and 92% discussed results with patients, particularly in the context of a possible HIV seroconversion illness (96%) or when deciding when to start antiretroviral therapy (70%). A third (36%) of specialists were initially concerned that RITA results may cause additional anxiety among patients; however, no adverse events were reported. The majority (90%) felt that results could assist with contact tracing by prioritizing patients with likely recent infection. However, only a few centres have currently incorporated RITA into their HIV partner notification protocols.

CONCLUSIONS

RITA has been introduced into clinical practice with no reported patient adverse events. Access to results at centre level should be improved. National guidance regarding use of RITA as a tool for contact tracing is required.

Standardization and monitoring of laboratory performance and quality assurance by use of the less-sensitive HIV incidence assay: seven years of results

BACKGROUND

The Performance Evaluation Program for HIV-1 incidence tests provided quality assurance services to laboratories conducting the serological testing algorithm for recent HIV seroconversion by use of a modified less-sensitive version of the Vironostika HIV-1 MicroElisa System assay. We report on the performance of the assay using proficiency testing and quality control materials tested from 2001 to 2008.

METHODS

Two sets of 5 blinded serum panels using common calibration and quality control materials were tested. The mean, standard deviation, and coefficient of variation were calculated. Results were analyzed for misclassifications: false recent HIV infection errors (long-term infection classified as HIV infection less than 1 year), false long-term infection errors (HIV infection less than 1 year classified as long-term infection), and differences in standardized optical density means and variances over time.

RESULTS

The false recent error rate was 1.26% (n = 2219). The false long-term error rate was 0.25% (n = 1618). No significant trends were observed for misclassification rates by year, and no significant trend in the standardized optical density over 7 years was observed.

CONCLUSIONS

Laboratories using the less-sensitive Vironostika HIV-1 assay produced consistent results by use of a common calibrator and quality control materials.

Emergence of an HIV-1 cluster harbouring the major protease L90M mutation among treatment-naïve patients in Tel Aviv, Israel

OBJECTIVE

Drug resistance-associated mutations (DRMs) among HIV-1 treatment-naïve patients have increased in recent years. Their incidence and prevalence in various exposure risk categories (ERCs) were evaluated.

DESIGN

Plasma samples of HIV-1 treatment-naïve patients diagnosed between 2001 and 2009 at the Tel Aviv Medical Center were screened for DRMs.

METHODS

Samples obtained from patients following the HIV diagnosis were analysed retrospectively. Genotyping was carried out using the Trugene HIV-1 genotype kit (Siemens, Berkeley, CA, USA). Phylogenetic relationships among viral sequences were estimated using the maximum likelihood method.

RESULTS

Thirty-eight of the 266 analysed sequences (14.3%) had DRMs, all occurring exclusively in the group of men who have sex with men (MSM). The rate of DRMs has constantly risen, reaching a peak of 21.9% in 2009. Notably, protease inhibitor (PI) DRMs became the most frequent DRMs in 2009. Phylogenetic analysis showed a tight cluster comprising 13 of 14 viruses harbouring the L90M major PI resistance mutation, suggesting a single infection source.

CONCLUSION

There was an unexpectedly high rate of the major L90M PI resistance mutation in the MSM group. The clustered transmission of this mutation might be related to a high-risk sexual behaviour. Added to nonnucleoside reverse transcriptase inhibitor and nucleoside reverse transcriptase inhibitor resistance mutations, such a PI mutation may limit future therapeutic options for this particular patient population.

Current and future assays for identifying recent HIV infections at the population level

The precise diagnosis of recent human immunodeficiency virus (HIV) infection is crucial for estimating HIV incidence, defined as the number of new infections in a population, per person at risk, during a specified time period. Incidence assessment is considered to be a tool for surveillance, public health and research. Differentiating recent from long-term HIV infections is possible thanks to the evaluation of HIV-specific immune response development or viral markers measurement. Several methods that enable the recognition of recent HIV-1 infection with the use of a single blood specimen have been developed, and their value for use in population level studies has been demonstrated. However, they are still inadequate due to a variable window period and false recent rates among HIV clades and across populations. Application of these assays at an individual level is far more questionable because of person-to-person variability in the antibody response and the course of HIV infection, and because of the prospective regulatory approval requirements.

In this article we review the principles and the limitations of the currently available major laboratory techniques that allow detection of recent HIV infection. The assays based on the alteration of serological parameters, as well as the newest method based on an increase of HIV genetic diversity with the progress of infection, are described.

Recent decline in the incidence of human immunodeficiency virus infection among California men who have sex with men

Monitoring the incidence of human immunodeficiency virus (HIV) infection among men who have sex with men (MSM) is imperative for developing targeted prevention programs and evaluating their effectiveness. The authors used California counseling and testing data to estimate the temporal trend in HIV incidence among MSM in California. HIV incidence rates were retrospectively calculated among MSM who had received at least 1 HIV test at a public California counseling and testing site between 1997 and 2007 and had a prior HIV-negative test from any HIV testing source. All study subjects were weighted on the basis of the interval between the last HIV-negative test and the current HIV test to account for the right-truncation bias introduced by more frequent testers. The authors observed that the HIV incidence rate among MSM in California increased from 2.0/100 person-years (95% confidence interval (CI): 1.8, 2.2) in 1997 to 2.4/100 person-years (95% CI: 2.2, 2.6) in 2003 and then decreased to 1.9/100 person-years (95% CI: 1.7, 2.0) in 2006. Trend analyses showed that both the increase (P < 0.001) and the decrease (P < 0.01) were statistically significant. The study showed that HIV incidence among MSM in California had decreased since 2003.

Prevalence of transmitted HIV drug resistance in Botswana: lessons learned from the HIVDR-Threshold Survey conducted among women presenting for routine antenatal care as part of the 2007 national sentinel survey

The emergence and spread of transmitted drug resistance (TDR) poses a major threat to the success of the rapidly expanding antiretroviral treatment (ART) programs in resource-limited countries. The World Health Organization recommends the use of the HIV Drug Resistance Threshold Survey (HIVDR-TS) as an affordable means to monitor the presence of TDR in these settings. We report our experiences and results of the 2007 HIVDR-TS in Botswana, a country with one of the longest-existing national public ART programs in Africa. The HIVDR-TS and HIV-1 incidence testing were performed in the two largest national sites as part of the 2007 antenatal Botswana Sentinel Survey. The HIVDR-TS showed no significant drug resistance mutations (TDR less than 5%) in one site. TDR prevalence, however, could not be ascertained at the second site due to low sample size. The agreement between HIVDR-TS eligibility criteria and laboratory-based methodologies (i.e., BED-CEIA and LS-EIA) in identifying recently HIV-1 infected adults was poor. Five years following the establishment of Botswana's public ART program, the prevalence of TDR remains low. The HIVDR-TS methodology has limitations for low-density populations as in Botswana, where the majority of antenatal sites are too small to recruit sufficient numbers of patients. In addition, the eligibility criteria (age <25 years and parity (first pregnancy)) of the HIVDR-TS performed poorly in identifying recent HIV-1 infections in Botswana. An alternative sampling strategy should be considered for the surveillance of HIVDR in Botswana and similar geographic settings.

Evaluation of HIV incidence surveillance in New York City, 2006

In 2005, the New York City (NYC) Department of Health and Mental Hygiene implemented a standardized human immunodeficiency virus (HIV) incidence surveillance protocol based on the serologic testing algorithm for recent HIV seroconversion deployed nationwide by the Centers for Disease Control and Prevention (CDC). We evaluated four key attributes of NYC's HIV incidence surveillance system-simplicity, data quality, timeliness, and acceptability--using CDC's guidelines for surveillance system evaluation. The evaluation revealed that the system could potentially provide HIV incidence estimates stratified by borough and major demographic groups at about nine months after the period of interest. The system strengths include its relative simplicity and integration with routine HIV/acquired immunodeficiency syndrome surveillance. Weaknesses include lack of completeness of testing history information, a critical component of incidence estimation. Continued improvements in data completeness and timeliness will improve the currently available information to inform personnel who develop HIV-prevention programs and policy initiatives in NYC and nationally.

Minimal impact of circumcision on HIV acquisition in men who have sex with men

BACKGROUND

Men who have sex with men (MSM) are disproportionately affected by HIV. The proven efficacy of circumcision in reducing the risk of HIV acquisition among African heterosexual males has raised the question of whether this protective effect may extend to MSM populations. We examined the potential impact of circumcision on an HIV epidemic within a population of MSM.

METHODS

A mathematical model was developed to simulate HIV transmission in an MSM population. The model incorporated both circumcision and seropositioning, and was used to predict the reduction in HIV prevalence and incidence as a result of the two interventions. Estimates for the time required to achieve these gains were also calculated.

RESULTS

We derive simple formulae for the decrease in HIV prevalence with increased circumcision. Our model predicts that if an initially uncircumcised MSM population in a developed country with a baseline HIV prevalence of 10% underwent universal circumcision, HIV incidence would only be reduced to 95% of pre-intervention levels and HIV prevalence to 9.6% after 20 years. In the longer term, our model predicts that prevalence would only decrease from 10% to 6%, but this would take several generations to achieve. The effectiveness of circumcision increases marginally with higher degrees of seropositioning.

CONCLUSIONS

The results of these calculations suggest that circumcision as a public health intervention will not produce a substantial decrease in HIV prevalence or incidence among MSM in the near future, and only modest reductions are achievable in the long-term.

Antiretroviral treatment of primary HIV infection to reduce onward transmission

PURPOSE OF REVIEW

This review will discuss the role of antiretroviral therapy to treat primary HIV infection (PHI) as a strategy to prevent onward viral transmission.

RECENT FINDINGS

Novel technology has greatly enhanced the appreciation of the characteristics of recently transmitted HIV-1 variants. Recent primate data demonstrate marked enhanced infectiousness of viral variants isolated from acutely infected macaques compared with viruses isolated from animals in the chronic phase of disease. These data are supported by phylogenetic analyses of recently transmitted cases in humans, implying that individuals with PHI may contribute disproportionately to onward transmission at a population level.

SUMMARY

In the absence of randomized clinical trial data supporting individual benefit of antiretroviral therapy, targeting and treating individuals with PHI as a public health intervention strategy represent a paradigm shift from current treatment strategies based around proven individual benefit alone. However, there is increasing evidence that PHI contributes disproportionately to viral transmission at a population level and failure to incorporate the potential role PHI plays, particularly in focused epidemics, maybe a naïve omission of many of the current mathematical models evaluating the impact of universal test and treat on population-level HIV incidence.

Epidemiological study of phylogenetic transmission clusters in a local HIV-1 epidemic reveals distinct differences between subtype B and non-B infections

Background

The number of HIV-1 infected individuals in the Western world continues to rise. More in-depth understanding of regional HIV-1 epidemics is necessary for the optimal design and adequate use of future prevention strategies. The use of a combination of phylogenetic analysis of HIV sequences, with data on patients' demographics, infection route, clinical information and laboratory results, will allow a better characterization of individuals responsible for local transmission.

Methods

Baseline HIV-1 pol sequences, obtained through routine drug-resistance testing, from 506 patients, newly diagnosed between 2001 and 2009, were used to construct phylogenetic trees and identify transmission-clusters. Patients' demographics, laboratory and clinical data, were retrieved anonymously. Statistical analysis was performed to identify subtype-specific and transmission-cluster-specific characteristics.

Results

Multivariate analysis showed significant differences between the 59.7% of individuals with subtype B infection and the 40.3% non-B infected individuals, with regard to route of transmission, origin, infection with Chlamydia (p = 0.01) and infection with Hepatitis C virus (p = 0.017). More and larger transmission-clusters were identified among the subtype B infections (p < 0.001). Overall, in multivariate analysis, clustering was significantly associated with Caucasian origin, infection through homosexual contact and younger age (all p < 0.001). Bivariate analysis additionally showed a correlation between clustering and syphilis (p < 0.001), higher CD4 counts (p = 0.002), Chlamydia infection (p = 0.013) and primary HIV (p = 0.017).

Conclusions

Combination of phylogenetics with demographic information, laboratory and clinical data, revealed that HIV-1 subtype B infected Caucasian men-who-have-sex-with-men with high prevalence of sexually transmitted diseases, account for the majority of local HIV-transmissions. This finding elucidates observed epidemiological trends through molecular analysis, and justifies sustained focus in prevention on this high risk group.

Frequent testing of highly sexually active gay men is required to control syphilis

BACKGROUND

The incidence of syphilis infections has been substantially increasing in gay men in the developed world.

METHODS

We developed an individual-based mathematical model describing syphilis transmission within a gay male population: we used the model to simulate the expected relative impact of numerous screening and treatment interventions, targeting different at-risk groups with various coverage and frequency rates and follow-up schedules.

RESULTS

The model predicts that increasing the proportion of gay men tested each year would have a relatively modest impact on syphilis incidence. However, increasing the frequency of testing can have a large impact, with the prevalence of syphilis reduced substantially if individuals are tested every 3 months. Targeting frequent screening at gay men who have large numbers of partners or who engage in group sex is a more efficient way of reducing syphilis epidemics. Contact tracing the regular partners of infected individuals is the most efficient intervention and can have a significant epidemiological impact with relatively high coverage rates.

CONCLUSIONS

Increasing the frequency of testing and treatment are required to mitigate syphilis epidemics. Notifying and testing partners of infected men should occur where possible but the high rates required to reverse epidemic trends are likely to be infeasible. Contact tracing should be a secondary priority that is coupled with increases in the frequency of testing in the population. Encouraging testing among men not previously tested for syphilis is also recommended.

Determinants of HIV-1 transmission in men who have sex with men: a combined clinical, epidemiological and phylogenetic approach

OBJECTIVES

To identify biological factors associated with HIV transmission in men who have sex with men (MSM).

DESIGN

A longitudinal phylogenetic analysis of HIV-1 from an MSM cohort, incorporating clinical and epidemiological data.

METHODS

Potential individuals were HIV-infected MSM attending a sexual health clinic between 2000 and 2006. Individuals were classified such that they could move from recent to chronic infection categories. HIV-1pol gene sequences were obtained from plasma virus or proviral DNA and clusters estimated by maximum likelihood and conservative genetic distance differences. The single most likely transmitter generating each recent infection was ascertained and risk factors around time of likely transmission explored using Poisson regression modelling.

RESULTS

Out of 1144 HIV-infected MSM, pol sequence data were obtained for 859 (75%); 159 out of 859 (19%) were recently HIV infected at diagnosis. A single most likely transmitter was identified for 41 out of 159 (26%), of which 11 were recently infected (27%) and 30 chronically infected. Factors associated with transmission in multivariable analysis were: younger age {rate ratio per 5 years older 0.68 [95% confidence interval (CI) 0.54-0.86], P=0.0009}, higher viral load [rate ratio per log higher 1.61 (95% CI 1.15-2.25), P=0.005], recent infection [rate ratio 3.88 (95% CI 1.76-8.55), P=0.0008] and recent sexually transmitted disease [rate ratio 5.32 (95% CI 2.51-11.29), P=0.0001]. HAART was highly protective in a univariable model, RR 0.14 (95% CI 0.07-0.27, P=0.0001).

CONCLUSION

Onward transmission of HIV among MSM is significantly associated with recent infection, sexually transmitted diseases and higher viral load, and reduced by effective HAART. The majority of new infections appear to occur from individuals whose infection was undiagnosed at the time of transmission.

HIV-1 transmission after cessation of early antiretroviral therapy among men having sex with men

OBJECTIVE

To study transmission dynamics during acute infection, during the aviremic phase over the period of early antiretroviral therapy (ART) and during the phase of viral rebound after early treatment was stopped.

METHODS

Transmission dynamics was assessed within 111 patients, enrolled in the Zurich primary HIV infection study, by molecular epidemiological methods using pol sequences from genotypic resistance tests and clonal env C2-V3-C3 sequences. Coclustering of Zurich primary HIV infection sequences with 12,303 sequences from 8837 HIV-positive patients enrolled in the multisite Swiss HIV Cohort Study was identified. Furthermore, we investigated transmission patterns within phylogenetic clusters by using longitudinal clinical data and analyzed HIV transmission by stage of infection and attempted to localize transmission events to periods before or after early ART.

RESULTS

Six transmission clusters comprising 20 men having sex with men were identified. Furthermore, linkage to eight men having sex with men from the Swiss HIV Cohort Study could be established. Strikingly, we detected at least five new primary infection events originating from Zurich primary HIV infection patients within 16-61 weeks after stopping early ART. Viral loads of likely index patients varied from 314 up to 1,690,000 HIV-1 RNA copies/ml of plasma at the estimated time of infection.

CONCLUSION

The large number of new infections originating from men having sex with men who stopped early ART indicates that current preventive efforts are insufficient. In contrast, these patients showed no adherence problems. These findings argue for early, continuous ART in sexually active HIV-1-infected persons not only for individual patient benefits but also specifically to reduce the spread of HIV-1.

Male circumcision to reduce the risk of HIV and sexually transmitted infections among men who have sex with men

PURPOSE OF REVIEW

The success of male circumcision in reducing HIV acquisition among African heterosexuals has led to renewed interest in this biological intervention for HIV/sexually transmissible infection (STI) prevention in men who have sex with men (MSM). This review summarizes the available data on the association of circumcision and HIV/STI among MSM populations.

RECENT FINDINGS

Results of observational studies indicate that circumcision has limited impact on HIV/STI acquisition among MSM populations overall. Longitudinal data suggest that circumcision may reduce the risk of incident syphilis, but there is little evidence of a protective effect for other STIs. The subgroup of MSM who predominantly practise the insertive role in anal intercourse may be at lower risk of HIV, although the relative inefficiency of HIV acquisition for insertive compared with receptive partners has resulted in imprecise estimates of effect.

SUMMARY

The evidence that circumcision reduces HIV and other STIs among MSM is weak and inconsistent. However, recent studies have found that circumcised MSM who predominantly take the insertive role in anal intercourse may be at a lower risk of HIV infection. Although MSM may be willing to undergo adult circumcision, should it be proven to reduce HIV acquisition risk, there is substantial potential that behavioural disinhibition could offset any benefits achieved by a circumcision intervention.

Access to highly active antiretroviral therapy (HAART) for women and children in the WHO European Region 2002-2006

Objective. To assess the level of access to highly active antiretroviral therapy (HAART) for women and children in the WHO European Region. Methods. Analysis of data from three national surveys of 53 WHO European Member States. The comparative level of access to HAART for women and children was assessed by comparing the percentage of reported HIV cases with the percentage of HAART recipients in women at the end of 2002 and 2006 and in children at the end of 2004 and 2006. Findings. Overall, the data suggest that there is equivalence of access to antiretroviral therapy by gender and age in Europe. However, in central and eastern Europe women were disproportionately more likely to receive HAART when compared with men in 2006, representing 29% of HIV cases when compared with 39% of HAART recipients in central Europe, and 34% of HIV cases when compared with 42% of HAART recipients in eastern Europe. In comparison with adults, children (<15 years of age) were over-represented among HAART recipients when compared with HIV cases in eastern Europe, accounting for 1% of HIV cases and 9% of people on HAART in 2004 and 1% of HIV cases and 8% HAART recipients in 2006. Conclusion. Access to HAART remains inequitable in terms of gender in central and eastern Europe, favouring women over men, and in terms of age in eastern Europe, favouring children over adults. Despite high and increasing coverage with HAART in many European countries, countries must address how to further increase the number of people on treatment while ensuring equitable access for all population groups in need.

Circumcision and risk of HIV infection in Australian homosexual men

OBJECTIVE

To assess circumcision status as a risk factor for HIV seroconversion in homosexual men.

DESIGN, SETTING AND PARTICIPANTS

The Health in Men (HIM) study was a prospective cohort of homosexual men in Sydney, Australia. HIV-negative men (n = 1426) were recruited primarily from community-based sources between 2001 and 2004 and followed to mid-2007. Participants underwent annual HIV testing, and detailed information on sexual risk behaviour was collected every 6 months.

MAIN OUTCOME MEASURE

HIV incidence in circumcised compared with uncircumcised participants, stratified by whether or not men predominantly practised the insertive role in anal intercourse.

RESULTS

There were 53 HIV seroconversions during follow-up; an incidence of 0.78 per 100 person-years. On multivariate analysis controlling for behavioural risk factors, being circumcised was associated with a nonsignificant reduction in risk of HIV seroconversion [hazard ratio 0.78, 95% confidence interval (CI) 0.42-1.45, P = 0.424]. Among one-third of study participants who reported a preference for the insertive role in anal intercourse, being circumcised was associated with a significant reduction in HIV incidence after controlling for age and unprotected anal intercourse (UAI) (hazard ratio 0.11, 95% CI 0.03-0.80, P = 0.041). Those who reported a preference for the insertive role overwhelmingly practised insertive rather than receptive UAI.

CONCLUSIONS

Overall, circumcision did not significantly reduce the risk of HIV infection in the HIM cohort. However, it was associated with a significant reduction in HIV incidence among those participants who reported a preference for the insertive role in anal intercourse. Circumcision may have a role as an HIV prevention intervention in this subset of homosexual men.

Potential impact of early antiretroviral therapy on transmission

PURPOSE OF REVIEW

In this review, we will discuss the potential of early highly active antiretroviral therapy (HAART) to reduce the sexual transmission of HIV on an individual and population level. We will focus on the biological plausibility and behavioural factors associated with HAART use and interventions that might influence such a strategy.

RECENT FINDINGS

Empiric and phylogenetic studies support the view that recent HIV infection is a highly infectious disease stage. Evidence increasingly demonstrates that individuals on fully suppressive HAART are significantly less likely to transmit HIV to sexual partners and some even suggest that such individuals cannot transmit HIV. Changes in risk behaviour are associated with the availability of HAART but behavioural studies offer contradictory observations regarding the direction and magnitude of these changes. This in turn makes the intricate assumptions and therefore outcomes of many complex mathematical modelling studies less secure. Furthermore, there is evidence that it is those individuals with undiagnosed HIV infection who contribute significantly to onward sexual transmission.

SUMMARY

At an individual level, HAART will reduce viral load and, therefore, infectiousness, although whether to zero or not remains controversial. At a population level, if recent infection and undiagnosed infections continue to drive onward transmission, earlier treatment will only alter the pandemic if accompanied by an improvement in diagnosing the undiagnosed and recognizing recent infection.

Importance of promoting HIV testing for preventing secondary transmissions: modelling the Australian HIV epidemic among men who have sex with men

BACKGROUND

We address the research questions: (i) what proportion of new HIV infections is transmitted from people who are (a) undiagnosed, (b) in primary HIV infection (PHI), (c) on antiretroviral therapy?; and (ii) what is the expected epidemiological impact of (a) increasing the proportion of newly acquired HIV infections receiving early treatment, and (b) increasing HIV testing rates?

METHODS

We used a mathematical model to simulate HIV transmission in the population of men who have sex with men (MSM) in Australia. We calibrated the model using established biological and clinical data and a wide range of Australian MSM epidemiological and behavioural data sources.

RESULTS

We estimate that ~19% of all new HIV infections are transmitted from the ~3% of Australian HIV-infected MSM who are in PHI; ~31% of new HIV infections are estimated to be transmitted from the ~9% of MSM with undiagnosed HIV. We estimate that the average number of infections caused per HIV-infected MSM through the duration of PHI is ~0.14-0.28.

CONCLUSIONS

The epidemiological impact of increasing treatment in PHI would be modest due to insufficient detection of newly-infected individuals. In contrast, increases in HIV testing rates could have substantial epidemiological consequences. The benefit of testing will also increase over time. Promoting increases in the coverage and frequency of testing for HIV could be a highly-effective public health intervention, but the population-level impact of interventions based on promoting early treatment of patients diagnosed in PHI is likely to be small. Treating PHI requires further evaluation of its long-term effects on HIV-infected individuals.

Implications of and perspectives on HIV surveillance using a serological method to measure recent HIV infections in newly diagnosed individuals: results from a pilot study in Berlin, Germany, in 2005-2007

OBJECTIVES

This cross-sectional study was designed to pilot the analysis of clinical data, knowledge about and attitudes towards HIV/AIDS, and prevention and risk behaviour in persons recently infected with HIV.

METHODS

Blood samples and demographic, laboratory, clinical and behavioural data were collected from patients with newly diagnosed HIV infections. The BED IgG-capture ELISA (BED-CEIA) was used to determine the recency of infection.

RESULTS

Recent HIV infections contributed 54% [95% confidence interval (CI) 45; 64%] of infections in men who have sex with men (MSM) and 16% (95% CI 0; 39%) of infections in patients with other transmission risks (P=0.041). Recently infected MSM were characterized by younger age and higher viral load as compared with MSM who had longstanding infections (P=0.011 and 0.005, respectively). Symptoms during primary infection and patients' assumptions with regard to time of infection were significantly correlated with test results indicating whether or not the HIV infection was recently acquired (P<0.001).

CONCLUSIONS

Cross-sectional surveillance of recent HIV infections proved to be relevant to the identification of current risks for acquiring HIV infection. The high proportion of recent HIV infections in MSM and the even higher proportion in MSM younger than 30 years indicate ongoing HIV transmission in this group. The method will be used in future national HIV surveillance in Germany.

Transmission networks of drug resistance acquired in primary/early stage HIV infection

OBJECTIVES

Population-based sequencing of primary/recent HIV infections (PHIs) can provide a framework for understanding transmission dynamics of local epidemics. In Quebec, half of PHIs represent clustered transmission events. This study ascertained the cumulative implications of clustering on onward transmission of drug resistance.

METHODS

HIV-1 pol sequence datasets were available for all genotyped PHI (<6 months postseroconversion; n = 848 subtype B infections, 1997-2007). Phylogenetic analysis established clustered transmission events, based on maximum likelihood topologies having high bootstrap values (>98%) and short genetic distances. The distributions of resistance to nucleoside and nonnucleoside reverse transcriptase inhibitors and protease inhibitors in unique and clustered transmissions were ascertained.

RESULTS

Episodic clustering was observed in half of recent/early stage infections from 1997-2008. Overall, 29 and 28% of new infections segregated into small (<5 PHI/cluster, n = 242/848) and large transmission chains (> or =5 PHI/cluster, n = 239/848), averaging 2.8 +/- 0.1 and 10.3 +/- 1.0 PHI/cluster, respectively. The transmission of nucleoside analogue mutations and 215 resistant variants (T215C/D/I/F/N/S/Y) declined with clustering (7.9 vs. 3.4 vs. 1.2 and 5.8 vs. 1.7 vs. 1.1% for unique, small, and large clustered transmissions, respectively). In contrast, clustering was associated with the increased transmission of viruses harbouring resistance to nonnucleoside reverse transcriptase inhibitors (6.6 vs. 6.0 vs. 15.5%, respectively).

CONCLUSION

Clustering in early/PHI stage infection differentially affects transmission of drug resistance to different drug classes. Public health, prevention and diagnostic strategies, targeting PHI, afford a unique opportunity to curb the spread of transmitted drug resistance.

Relation between HIV viral load and infectiousness: a model-based analysis

BACKGROUND

A consensus statement released on behalf of the Swiss Federal Commission for HIV/AIDS suggests that people receiving effective antiretroviral therapy-ie, those with undetectable plasma HIV RNA (<40 copies per mL)-are sexually non-infectious. We analysed the implications of this statement at a population level.

METHODS

We used a simple mathematical model to estimate the cumulative risk of HIV transmission from effectively treated HIV-infected patients (HIV RNA <10 copies per mL) over a prolonged period. We investigated the risk of unprotected sexual transmission per act and cumulatively over many exposures, within couples initially discordant for HIV status.

FINDINGS

Assuming that each couple had 100 sexual encounters per year, the cumulative probability of transmission to the serodiscordant partner each year is 0.0022 (uncertainty bounds 0.0008-0.0058) for female-to-male transmission, 0.0043 (0.0016-0.0115) for male-to-female transmission, and 0.043 (0.0159-0.1097) for male-to-male transmission. In a population of 10 000 serodiscordant partnerships, over 10 years the expected number of seroconversions would be 215 (80-564) for female-to-male transmission, 425 (159-1096) for male-to-female transmission, and 3524 (1477-6871) for male-to-male transmission, corresponding to an increase in incidence of four times compared with incidence under current rates of condom use.

INTERPRETATION

Our analyses suggest that the risk of HIV transmission in heterosexual partnerships in the presence of effective treatment is low but non-zero and that the transmission risk in male homosexual partnerships is high over repeated exposures. If the claim of non-infectiousness in effectively treated patients was widely accepted, and condom use subsequently declined, then there is the potential for substantial increases in HIV incidence.

FUNDING

Australian Research Council.