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Featured researches published by Axel J. Schmidt.


PLOS ONE | 2011

Trouble with Bleeding: Risk Factors for Acute Hepatitis C among HIV-Positive Gay Men from Germany—A Case-Control Study

Axel J. Schmidt; Jürgen K. Rockstroh; Martin Vogel; Matthias an der Heiden; Armin Baillot; Ivanka Krznaric; Doris Radun

Objectives To identify risk factors for hepatitis C among HIV-positive men who have sex with men (MSM), focusing on potential sexual, nosocomial, and other non-sexual determinants. Background Outbreaks of hepatitis C virus (HCV) infections among HIV-positive MSM have been reported by clinicians in post-industrialized countries since 2000. The sexual acquisition of HCV by gay men who are HIV positive is not, however, fully understood. Methods Between 2006 and 2008, a case-control study was embedded into a behavioural survey of MSM in Germany. Cases were HIV-positive and acutely HCV-co-infected, with no history of injection drug use. HIV-positive MSM without known HCV infection, matched for age group, served as controls. The HCV-serostatus of controls was assessed by serological testing of dried blood specimens. Univariable and multivariable regression analyses were used to identify factors independently associated with HCV-co-infection. Results 34 cases and 67 controls were included. Sex-associated rectal bleeding, receptive fisting and snorting cocaine/amphetamines, combined with group sex, were independently associated with case status. Among cases, surgical interventions overlapped with sex-associated rectal bleeding. Conclusions Sexual practices leading to rectal bleeding, and snorting drugs in settings of increased HCV-prevalence are risk factors for acute hepatitis C. We suggest that sharing snorting equipment as well as sharing sexual partners might be modes of sexual transmission. Condoms and gloves may not provide adequate protection if they are contaminated with blood. Public health interventions for HIV-positive gay men should address the role of blood in sexual risk behaviour. Further research is needed into the interplay of proctosurgery and sex-associated rectal bleeding.


Social Science & Medicine | 2013

Structural and environmental factors are associated with internalised homonegativity in men who have sex with men : Findings from the European MSM Internet Survey (EMIS) in 38 countries

Rigmor C. Berg; Michael W. Ross; Peter Weatherburn; Axel J. Schmidt

Internalised homonegativity refers to a gay persons negative feelings about homosexuality and is believed to stem from negative societal stereotypes and attitudes towards homosexuality. Surprisingly, little research has centred on this link. In this research, we aimed to examine the associations between internalised homonegativity and structural forces, cultural influence, and access to sexual health promotion measures among a sample of 144,177 men who have sex with men (MSM) in 38 European countries. Participants were recruited as part of the European MSM Internet Survey (EMIS) during 2010. It was a self-completion, multilingual Internet-based survey for men living in Europe who have sex with men and/or feel attracted to men. Assumed causal relations were tested through multiple regression models. Variables at the structure of rule-systems (macro-level) that were significantly and negatively associated with internalised homonegativity were the presence of laws recognising same-sex relationships and same-sex adoption. In the meso-level model, greater proportions of the population expressing that they would not like to have homosexuals as neighbours predicted higher internalised homonegativity. In the last model, five variables were significantly and negatively associated with internalised homonegativity: being exposed to HIV/STI information for MSM, access to HIV testing, access to STI testing, access to condoms, and experience of gay-related hostility. In turn, men who had tested for HIV in the past year evidenced lower internalised homonegativity. This is the largest and certainly most geographically diverse study to date to examine structural and environmental predictors of internalised homonegativity among MSM. Our results show that one insidious consequence of societys stigma towards homosexuals is the internalisation of that stigma by gay and bisexual men themselves, thus, drawing attention to the importance of promoting social equity for self-acceptance around gay identity in building a positive sense of self.


AIDS | 2015

Hidden from health: structural stigma, sexual orientation concealment, and HIV across 38 countries in the European MSM Internet Survey

John E. Pachankis; Mark L. Hatzenbuehler; Ford Hickson; Peter Weatherburn; Rigmor C. Berg; Ulrich Marcus; Axel J. Schmidt

Objective:Substantial country-level variation exists in prejudiced attitudes towards male homosexuality and in the extent to which countries promote the unequal treatment of MSM through discriminatory laws. The impact and underlying mechanisms of country-level stigma on odds of diagnosed HIV, sexual opportunities, and experience of HIV-prevention services, needs and behaviours have rarely been examined, however. Design:Data come from the European MSM Internet Survey (EMIS), which was administered between June and August 2010 across 38 European countries (N = 174 209). Methods:Country-level stigma was assessed using a combination of national laws and policies affecting sexual minorities and a measure of attitudes held by the citizens of each country. We also assessed concealment, HIV status, number of past 12-month male sex partners, and eight HIV-preventive services, knowledge, and behavioural outcomes. Results:MSM living in countries with higher levels of stigma had reduced odds of diagnosed HIV and fewer partners but higher odds of sexual risk behaviour, unmet prevention needs, not using testing services, and not discussing their sexuality in testing services. Sexual orientation concealment mediated associations between country-level stigma and these outcomes. Conclusion:Country-level stigma may have historically limited HIV transmission opportunities among MSM, but by restricting MSMs public visibility, it also reduces MSMs ability to access HIV-preventive services, knowledge and precautionary behaviours. These findings suggest that MSM in European countries with high levels of stigma are vulnerable to HIV infection. Although they have less opportunity to identify and contact other MSM, this might change with emerging technologies.


BMJ Open | 2013

Internalised homonegativity predicts HIV-associated risk behavior in European men who have sex with men in a 38-country cross-sectional study: some public health implications of homophobia

Michael W. Ross; Rigmor C. Berg; Axel J. Schmidt; Harm J. Hospers; Michele Breveglieri; Martina Furegato; Peter Weatherburn

Objectives Internalised homonegativity (IH) is hypothesised to be associated with HIV risk behaviour and HIV testing in men who have sex with men (MSM). We sought to determine the social and individual variables associated with IH and the associations between IH and HIV-related behaviours. Design and setting We examined IH and its predictors as part of a larger Internet-delivered, cross-sectional study on HIV and health in MSM in 38 European countries. Participants 181 495 MSM, IH data analysis subsample 144 177. All participants were male, over the age of consent for homosexual activity in their country of domicile, and have had at least one homosexual contact in the past 6 months. Methodology An anonymous Internet-based questionnaire was disseminated in 25 languages through MSM social media, websites and organisations and responses saved to a UK-based server. IH was measured using a standardised, cross-culturally appropriate scale. Results Three clusters of European countries based on the level of experienced discrimination emerged. IH was predicted by country LGB (lesbian, gay and bisexual) legal climate, Gini coefficient and size of place of settlement. Lower IH was associated with degree the respondent was ‘out’ as gay to others and older age. ‘Outness’ was associated with ever having an HIV test and age, education and number of gay friends, while IH (controlling for the number of non-steady unprotected sex partners and perceived lack of control over safe sex) was associated with condom use for anal intercourse. Conclusions IH is associated with LGB legal climate, economic development indices and urbanisation. It is also associated with ‘outness’ and with HIV risk and preventive behaviours including HIV testing, perceived control over sexual risk and condom use. Homonegative climate is associated with IH and higher levels of HIV-associated risk in MSM. Reducing IH through attention to LGB human rights may be appropriate HIV reduction intervention for MSM.


Sexual Health | 2011

HIV serosorting among HIV-positive men who have sex with men is associated with increased self-reported incidence of bacterial sexually transmissible infections

Ulrich Marcus; Axel J. Schmidt; Osamah Hamouda

BACKGROUND We aimed to quantify the frequency of HIV serosorting among men who have sex with men (MSM) in Germany, and evaluate the association of serosorting with other sexual risk management approaches (RMA) and with the frequency of bacterial sexually transmissible infections (STI). METHODS An anonymous, self-administered questionnaire was distributed through German online sexual networking sites and medical practices in 2006. The analysis was based on 2985 respondents who reported an HIV test result. Based on two questions on RMA, serosorting was classified as tactical (an event-based decision) or strategic (a premeditated search for a seroconcordant partner). The analysis was stratified by HIV serostatus and seroconcordant partnership status. RESULTS HIV serosorting patterns were different for HIV-positive and HIV-negative participants. Tactical serosorting ranked second after RMA based on condom use (HIV-positive: 55.1%, HIV-negative: 45.1%; P < 0.001). While the overlap of strategic and tactical HIV serosorting among HIV-positive MSM was substantial (58.0%), HIV-negative strategic and tactical serosorting were more distinct (18.1% overlap). Among HIV-positive and HIV-negative respondents, tactical serosorting was associated with reduced condom use. Compared with respondents using RMA other than serosorting, HIV-positive men reporting serosorting had a three-fold increased risk for bacterial STI (strategic: odds ratio (OR) = 2.62; 95% confidence interval (CI): 1.76-3.89; tactical: OR = 3.19; 95% CI: 2.14-4.75; both for respondents without HIV seroconcordant partners). CONCLUSIONS HIV serosorting has emerged as a common RMA among MSM. For HIV-positive MSM, it may contribute to high rates of bacterial STI that may lead to elevated per-contact risks for HIV transmission.


AIDS | 2015

The HIV care cascade in Switzerland: reaching the UNAIDS/WHO targets for patients diagnosed with HIV.

Philipp Kohler; Axel J. Schmidt; Matthias Cavassini; Hansjakob Furrer; Alexandra Calmy; Manuel Battegay; Enos Bernasconi; Bruno Ledergerber; Pietro Vernazza

Objectives:To describe the HIV care cascade for Switzerland in the year 2012. Design/methods:Six levels were defined: (i) HIV-infected, (ii) HIV-diagnosed, (iii) linked to care, (iv) retained in care, (v) on antiretroviral treatment (ART), and (vi) with suppressed viral load. We used data from the Swiss HIV Cohort Study (SHCS) complemented by a nationwide survey among SHCS physicians to estimate the number of HIV-patients not registered in the cohort. We also used Swiss ART sales data to estimate the number of patients treated outside the SHCS network. Based on the number of patients retained in care, we inferred the estimates for levels (i) to (iii) from previously published data. Results:We estimate that (i) 15 200 HIV-infected individuals lived in Switzerland in 2012 (margins of uncertainty, 13 400–19 300). Of those, (ii) 12 300 (81%) were diagnosed, (iii) 12 200 (80%) linked, and (iv) 11 900 (79%) retained in care. Broadly based on SHCS network data, (v) 10 800 (71%) patients were receiving ART, and (vi) 10 400 (68%) had suppressed (<200 copies/ml) viral loads. The vast majority (95%) of patients retained in care were followed within the SHCS network, with 76% registered in the cohort. Conclusion:Our estimate for HIV-infected individuals in Switzerland is substantially lower than previously reported, halving previous national HIV prevalence estimates to 0.2%. In Switzerland in 2012, 91% of patients in care were receiving ART, and 96% of patients on ART had suppressed viral load, meeting recent UNAIDS/WHO targets.


BMC Public Health | 2012

Prevalence of HIV among MSM in Europe: comparison of self-reported diagnoses from a large scale internet survey and existing national estimates

Ulrich Marcus; Ford Hickson; Peter Weatherburn; Axel J. Schmidt

BackgroundCountry level comparisons of HIV prevalence among men having sex with men (MSM) is challenging for a variety of reasons, including differences in the definition and measurement of the denominator group, recruitment strategies and the HIV detection methods. To assess their comparability, self-reported data on HIV diagnoses in a 2010 pan-European MSM internet survey (EMIS) were compared with pre-existing estimates of HIV prevalence in MSM from a variety of European countries.MethodsThe first pan-European survey of MSM recruited more than 180,000 men from 38 countries across Europe and included questions on the year and result of last HIV test. HIV prevalence as measured in EMIS was compared with national estimates of HIV prevalence based on studies using biological measurements or modelling approaches to explore the degree of agreement between different methods. Existing estimates were taken from Dublin Declaration Monitoring Reports or UNAIDS country fact sheets, and were verified by contacting the nominated contact points for HIV surveillance in EU/EEA countries.ResultsThe EMIS self-reported measurements of HIV prevalence were strongly correlated with existing estimates based on biological measurement and modelling studies using surveillance data (R2=0.70 resp. 0.72). In most countries HIV positive MSM appeared disproportionately likely to participate in EMIS, and prevalences as measured in EMIS are approximately twice the estimates based on existing estimates.ConclusionsComparison of diagnosed HIV prevalence as measured in EMIS with pre-existing estimates based on biological measurements using varied sampling frames (e.g. Respondent Driven Sampling, Time and Location Sampling) demonstrates a high correlation and suggests similar selection biases from both types of studies. For comparison with modelled estimates the self-selection bias of the Internet survey with increased participation of men diagnosed with HIV has to be taken into account. For most countries self-reported EMIS prevalence is higher than measured prevalence, which is likely due to a combination of different time points of measurement, measurement errors for small sample sizes, different sampling methods, and an indicator-inherent overestimate of prevalence among the untested fraction of MSM.


BMC Public Health | 2013

Estimating the size of the MSM populations for 38 European countries by calculating the survey-surveillance discrepancies (SSD) between self-reported new HIV diagnoses from the European MSM internet survey (EMIS) and surveillance-reported HIV diagnoses among MSM in 2009

Ulrich Marcus; Ford Hickson; Peter Weatherburn; Axel J. Schmidt

BackgroundComparison of rates of newly diagnosed HIV infections among MSM across countries is challenging for a variety of reasons, including the unknown size of MSM populations. In this paper we propose a method of triangulating surveillance data with data collected in a pan-European MSM Internet Survey (EMIS) to estimate the sizes of the national MSM populations and the rates at which HIV is being diagnosed amongst them by calculating survey-surveillance discrepancies (SSD) as a measure of selection biases of survey participants.MethodsIn 2010, the first EMIS collected self-reported data on HIV diagnoses among more than 180,000 MSM in 38 countries of Europe. These data were compared with data from national HIV surveillance systems to explore possible sampling and reporting biases in the two approaches. The Survey-Surveillance Discrepancy (SSD) represents the ratio of survey members diagnosed in 2009 (HIVsvy) to total survey members (Nsvy), divided by the ratio of surveillance reports of diagnoses in 2009 (HIVpop) to the estimated total MSM population (Npop). As differences in household internet access may be a key component of survey selection biases, we analysed the relationship between household internet access and SSD in countries conducting consecutive MSM internet surveys at different time points with increasing levels of internet access. The empirically defined SSD was used to calculate the respective MSM population sizes (Npop), using the formula Npop = HIVpop*Nsvy*SSD/HIVsvy.ResultsSurvey-surveillance discrepancies for consecutive MSM internet surveys between 2003 and 2010 with different levels of household internet access were best described by a potential equation, with high SSD at low internet access, declining to a level around 2 with broad access. The lowest SSD was calculated for the Netherlands with 1.8, the highest for Moldova with 9.0. Taking the best available estimate for surveillance reports of HIV diagnoses among MSM in 2009 (HIVpop), the relative MSM population sizes were between 0.03% and 5.6% of the adult male population aged 15–64. The correlation between recently diagnosed (2009) HIV in EMIS participants and HIV diagnosed among MSM in 2009 as reported in the national surveillance systems was very high (R2 = 0.88) when using the calculated MSM population size.ConclusionsNpop and HIVpop were unreliably low for several countries. We discuss and identify possible measurement errors for countries with calculated MSM population sizes above 3% and below 1% of the adult male population. In most cases the number of new HIV diagnoses in MSM in the surveillance system appears too low. In some cases, measurement errors may be due to small EMIS sample sizes. It must be assumed that the SSD is modified by country-specific factors.Comparison of community-based survey data with surveillance data suggests only minor sampling biases in the former that – except for a few countries - do not seriously distort inter-country comparability, despite large variations in participation rates across countries. Internet surveys are useful complements to national surveillance systems, highlighting deficiencies and allowing estimates of the range of newly diagnosed infections among MSM in countries where surveillance systems fail to accurately provide such data.


Sexually Transmitted Infections | 2013

Comparison of the performance of STI Screening Services for gay and bisexual men across 40 European cities: results from the European MSM Internet Survey

Axel J. Schmidt; Ford Hickson; Peter Weatherburn; Ulrich Marcus

Objectives Sexually transmitted infections (STIs) such as anal/genital warts, syphilis and genital/rectal gonorrhoeal/chlamydial infections compromise the health of men who have sex with men (MSM). Rectal bacterial STIs increase the per-contact risk of HIV infection. Early detection of asymptomatic STIs requires regular screening including collection of clinical specimens (or, for warts: physical examinations) that allow for the detection of infections at sites common to mens same sex practices. Methods From June to August 2010, the European MSM Internet Survey recruited 174 209 men from 38 European countries to an anonymous online questionnaire in 25 languages. As sexual healthcare for MSM in most countries is organised locally, we chose cities for comparison. Multivariable regression models were used to compare accessibility of services and applied diagnostic procedures across 40 cities. Results The proportion of respondents tested for STIs in the last 12 months in the absence of symptoms ranged from 8.9% in Istanbul to 48.0% in Amsterdam. At city level, low STI screening correlated with inaccessible services (R2=44.1%). At individual level, anal/penile inspection and anal swabbing was most common in UK cities, Amsterdam, Dublin and Stockholm. Compared to London, MSM in 30 cities had an adjusted OR (AOR) of (0.02 to 0.18) for anal swabbing; and (0.06 to 0.25) for anal/penile inspection (p<0.001). Conclusions Anal/genital warts and rectal infections are likely to be profoundly underdiagnosed among MSM in most European cities. This has implications for the sexual health of MSM, HIV prevention and comparing national surveillance data. There is an urgent need to improve sexual healthcare tailored to MSM at risk for STIs.


BMC Public Health | 2009

The denominator problem: Estimating MSM-specific incidence of sexually transmitted infections and prevalence of HIV using population sizes of MSM derived from Internet surveys

Ulrich Marcus; Axel J. Schmidt; Christian Kollan; Osamah Hamouda

BackgroundMeasuring prevalence and incidence of sexually transmitted infections in hard to reach populations like men who have sex with men (MSM) is hampered by unknown size and regional distribution of this population. Community sample – and study-based measurements are often fraught with participation biases and do not allow generalization of the results for other regions or the whole population group of MSM.MethodsWe used the proportional regional distribution of participants of large internet-based surveys among MSM from Germany together with a general population survey-derived estimate of the MSM population to estimate regional population sizes. Based on transmission group category from surveillance data and regional MSM population size we calculated regional population-specific incidence rates of newly diagnosed HIV infection and syphilis. For HIV prevalence we compared estimates of prevalent HIV infections in MSM from a surveillance data-based model with a mixed model in which we used the proportional regional distribution of HIV positive participants from surveys and the estimated total number of prevalent HIV infections from the surveillance based model.ResultsAssuming a similar regional distribution of survey participants and the MSM population as a whole, the regional proportion of MSM in the general population can be estimated. Regional incidence calculated with the estimated MSM population as denominator and national surveillance data as numerator results in regional peak incidence rates of 7–8 per 1,000 MSM for newly diagnosed HIV infection and syphilis. The gradient between metropolitan and rural areas narrows considerably compared with calculations which use the total (male) population as denominator. Regional HIV prevalence estimates are comparable in the two models.ConclusionConsidering the difficulties to obtain regionally representative data by other sampling methods for MSM, in Western post-industrialized countries internet-based surveys may provide an easy and low cost tool to estimate regional population distributions. With national surveillance data, which categorize transmission groups, regional population-specific incidence rates for reportable sexually transmitted infections can be estimated. HIV prevalence estimates for regional MSM populations show differences related to the level of urbanization, MSM concentration, and starting points of the HIV epidemic in western and eastern Germany.

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Rigmor C. Berg

Norwegian Institute of Public Health

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Michael Bochow

Social Science Research Center Berlin

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