Risk behaviour and sexually transmitted diseases are on the rise in gay men, but what is happening with HIV?

Diverging trends in incidence of HIV versus other sexually transmitted infections in HIV-negative MSM in Amsterdam

OBJECTIVES

We investigated changes in incidence rates of HIV and sexually transmitted infections (STIs) and trends in sexual behavior in MSM from 2009 to 2017.

DESIGN

Open prospective cohort study.

METHODS

HIV-negative MSM enrolled in the Amsterdam Cohort Studies were included. Participants semiannually completed a questionnaire on sexual behavior and were tested for HIV-1, syphilis, and urethral, anal and pharyngeal chlamydia and gonorrhea. Time trends in incidence rates were analyzed using exponential survival models.

RESULTS

During follow-up, 42 of 905 MSM acquired HIV. The HIV incidence rate was 1.9/100 person-years [95% confidence interval (CI) 1.0-3.7] in 2009 and decreased to 0.5/100 person-years (95% CI 0.2-1.4) in 2017 (P = 0.03). The largest decrease was observed in participants aged at least 35 years (P = 0.005), while the trend remained stable in 18-34 year olds (P = 0.4). The incidence rate for any bacterial STI was 16.8/100 person-years (95% CI 13.4-21.0) in 2010, and increased to 33.1/100 person-years (95% CI 29.0-37.9) in 2017 (P < 0.001). Between 2009 and 2017, the percentage reporting condomless anal sex with casual partners increased from 26.9 to 39.4% (P < 0.001), and the mean number of casual partners from eight (95% CI 8-8) to 11 (95% CI 10-11) (P = 0.05). Condomless anal sex with steady partner(s) remained stable over time (P = 0.5).

CONCLUSION

Among MSM in Amsterdam, incidence rates of HIV versus other STI show diverging trends. The increase in STI incidence coincides with a decrease in condom use with casual partners. The decrease in HIV incidence, despite increased sexual risk behavior, suggests that other HIV prevention methods have been successful in reducing HIV transmission among MSM.

As through a glass, darkly: the future of sexually transmissible infections among gay, bisexual and other men who have sex with men

The trajectory of sexually transmissible infection (STI) incidence among gay and other men who have sex with men (MSM) suggests that incidence will likely remain high in the near future. STIs were hyperendemic globally among MSM in the decades preceding the HIV epidemic. Significant changes among MSM as a response to the HIV epidemic, caused STI incidence to decline, reaching historical nadirs in the mid-1990s. With the advent of antiretroviral treatment (ART), HIV-related mortality and morbidity declined significantly in that decade. Concurrently, STI incidence resurged among MSM and increased in scope and geographic magnitude. By 2000, bacterial STIs were universally resurgent among MSM, reaching or exceeding pre-HIV levels. While the evidence base necessary for assessing the burden STIs among MSM, both across time and across regions, continues to be lacking, recent progress has been made in this respect. Current epidemiology indicates a continuing and increasing trajectory of STI incidence among MSM. Yet increased reported case incidence of gonorrhoea is likely confounded by additional screening and identification of an existing burden of infection. Conversely, more MSM may be diagnosed and treated in the context of HIV care or as part of routine management of pre-exposure prophylaxis (PrEP), potentially reducing transmission. Optimistically, uptake of human papillomavirus (HPV) vaccination may lead to a near-elimination of genital warts and reductions in HPV-related cancers. Moreover, structural changes are occurring with respect to sexual minorities in social and civic life that may offer new opportunities, as well as exacerbate existing challenges, for STI prevention among MSM.

Is Group Sex a Higher-Risk Setting for HIV and Other Sexually Transmitted Infections Compared With Dyadic Sex Among Men Who Have Sex With Men?

BACKGROUND

Group sex has been suggested as a potential high-risk setting for HIV and other sexually transmitted infections (STIs) among men who have sex with men (MSM). We investigated whether group sex is associated with lower condom use during anal sex and higher proportions of STIs compared with dyadic sex among HIV-negative MSM between 2009 and 2012.

METHODS

Cross-sectional data from 7 data waves of the Amsterdam Cohort Studies were used. The sample consisted of 465 MSM who either reported both group and dyadic sex (at n = 706 visits) or dyadic sex only (at n = 1339 visits) in the preceding 6 months. Logistic regression with generalized estimating equations was used to investigate the association between sexual setting (group vs. dyadic sex), condomless anal sex, and STI.

RESULTS

Group sex was reported at 35% (706/2045) of visits. Condomless sex was more often reported during dyadic than group sex (odds ratio, 3.64 95% confidence interval, 2.57-5.16). Men who had group sex were more likely diagnosed as having gonorrhea compared with men with dyadic sex (odds ratio, 1.71; 95% confidence interval, 1.08-2.97), but this effect was not retained in the multivariate model.

CONCLUSIONS

Results demonstrate within-person differences in sexual behavior during group and dyadic sex among MSM. Men were more likely to use condoms during group sex than during dyadic sex. Thus, for some, group sex may not necessarily be risky for HIV infection compared with dyadic sex. However, group sex may be a higher-risk setting for acquiring STIs other than HIV, such as gonorrhea. Group sex encounters should be recognized as distinct sexual settings with specific risk characteristics that need to be addressed accordingly.

Methodological Issues in Identifying Sexuality for Research

Sexuality is a complex concept that can be measured based on various aspects. Depending on the variable of interest, investigators may wish to focus on sexual behavior (activity), sexual orientation (attraction to a particular gender), or sexual identity (self-identification with a particular group of people). Further complicating the process is the fact that these aspects of sexuality are not always congruent with one another. Lesbian, gay, and bisexuals (LGB) are sexual minorities that have been identified as one of several groups that experience health disparities. For researchers working with the LGB population, properly identifying and defining which aspect of sexuality is of interest to the investigator is paramount in obtaining accurate outcomes.

The potential impact of an HIV vaccine with limited protection on HIV incidence in Thailand: a modeling study

BACKGROUND

The RV144 trial on the ALVAC/AIDSVAX candidate HIV vaccine, carried out in Thailand, showed short-lived protection against infection.

METHODS

Using a deterministic compartmental model we explored the potential impact of this vaccine on heterosexual HIV transmission in Thailand. Both one-off vaccination strategies, as well as strategies with regular boosting, either annually or every two years, were explored. Both targeting the general adult population and prioritizing sex workers were modeled. The impact of risk compensation among high risk groups, as well as whether higher levels of safe sex in high risk groups could be an alternative to vaccination, was studied.

RESULTS

One-off vaccination campaigns had only transient effects, and boosting appears to be a key component of successful vaccination campaigns. Intensive vaccination campaigns may reduce HIV incidence by up to 75% after 10 years of vaccination. Targeting only sex workers has a smaller impact but has a more favorable cost-benefit ratio. Risk compensation has the potential of undoing much of the benefits of a vaccination program and may even increase incidence. In contrast, higher levels of safe sex among sex workers would provide a viable alternative to vaccinating this group.

DISCUSSION

The new vaccine holds promise for controlling HIV in Thailand and similar countries. In view of the short lived protection of the vaccine, regular boosting of immunity as well as avoidance of risk compensation are essential. Targeting sex workers would achieve the greatest reduction in incidence per vaccination and may be considered for expensive vaccines but its cost-effectiveness has to be compared to alternatives.

Ongoing HIV-1 transmission among men who have sex with men in Amsterdam: a 25-year prospective cohort study

BACKGROUND

To examine the suggested resurgence of the HIV epidemic among men who have sex with men (MSM), we studied trends in HIV-1 incidence rates, sexual risk behaviour, risk factors for HIV-1 seroconversion, and source of HIV-1 infection among MSM in the Amsterdam Cohort Studies from 1984 to 2009.

METHODS

Trends in HIV-1 incidence and risk factors for HIV-1 infection were studied using Poisson regression. Trends in sexual risk behaviour were evaluated using logistic regression, correcting for intra-individual correlation via generalized estimating equations. Trends in the source of HIV-1 infection were modelled via logistic regression.

RESULTS

Of 1642 HIV-1-negative individuals, 217 seroconverted during follow-up. HIV-1 incidence rates strongly decreased from 8.6/100 person-years in 1985 to 1.3/100 person-years in 1992; remained relatively stable around 1.0/100 person-years between 1992 and 1996, and slowly increased to 2.0/100 person-years in 2009 (P = 0.14; linear trend 1996-2009). Reports of unprotected anal intercourse (UAI) increased significantly from 1996 onwards. HIV-1 seroconversion was associated with receptive UAI with casual partners, more than five sexual partners, a history of gonorrhoea (all in the preceding 6 months), and a lower educational level. Currently, MSM are more likely to have contracted HIV-1 from casual partners than from steady partners, but trends of recent years suggest that steady partners became a growing source with increasing age.

CONCLUSIONS

Following increases in sexual risk behaviour from 1996 onwards, HIV-1 continues to spread among MSM. Targeted prevention messages should continue to focus on sexual behaviour with casual partners, but also on sexual behaviour within steady relationships.

Condom use in multi-partnered males: importance of HIV and hepatitis B status

The objective of the research was to determine the demographic, sexual and social risk factors associated with condom use in 7,089 multi-partnered men attending the Sydney Sexual Health Centre. A review of computerized medical records from 1991 to 1999 was carried out. Males with two or more partners in the last three months were divided into three condom use groups: consistent, sometimes and never. Men reporting sex with men (MSM) were more likely to use condoms than men having sex with only women (p=0.001). HIV positive men were more likely to use condoms consistently than those who were negative (p=0.001). In HIV negative non-hepatitis-B carriers, factors independently associated with inconsistent condom use included alcohol consumption, intravenous drug use (odds ratio (OR) 0.6 (95% confidence interval (CI) 0.47-0.77)) and being married (OR 0.2 (95% CI 0.21-0.31)). Factors associated with consistent condom use were MSM (OR 1.8 (95% CI 1.26-2.49)) and having three or more partners in the last 3 months (OR 2.4 (95% CI 2.023-2.83)). In the 508 hepatitis B carriers, consistent condom users were less likely to be married or intravenous drug users (OR 0.4 (95% CI 0.23-0.85)). In the 200 HIV antibody positive men, those with three or more partners were less likely to be consistent condom users than those with two (OR 0.3 (95% CI 0.11-0.82)). The conclusions are that a small number of HIV positive men report unsafe sex with multiple partners. Health promotion activities should be directed at this group.

Sexual risk behaviours and HIV-1 prevalence among urban men who have sex with men in Cape Town, South Africa

BACKGROUND

Distinct homosexual and heterosexual HIV epidemics have previously been recognised in South Africa. However, linked HIV prevalence and self-reported sexual risk behaviour data have not been reported for men who have sex with men (MSM) in Cape Town since 1986.

METHODS

We conducted a cross-sectional, anonymous, venue-based HIV risk behaviour and prevalence study of 542 self-identified MSM in greater Cape Town using a self-administered risk questionnaire and the OraSure testing device to asses HIV-1 prevalence.

RESULTS

This sample had an overall HIV prevalence of 10.4% (56/539). We found that self-identifying as gay, homosexual or queer (adjusted odds ratio (AOR) 4.5, 95% confidence interval (CI) 1.0-20.0) and reporting ever having had a sexually transmissible infection diagnosis (AOR 4.3, 95% CI: 2.3-8.3) were significantly predictive of testing HIV-1 positive, while reporting unprotected anal intercourse with a known HIV-negative partner (AOR 0.4, 95% CI: 0.2-0.9) was significantly protective.

CONCLUSION

These data suggest a mature epidemic with consistent high-risk taking among MSM in Cape Town, and significant associations of select self-reported risk behaviours and HIV-1 serostatus. There is a need for continued and robust HIV surveillance along with detailed risk behaviour trends over time to inform the development of targeted risk-reduction interventions for this population.

27 years of the HIV epidemic amongst men having sex with men in the Netherlands: an in depth mathematical model-based analysis

BACKGROUND

There has been increasing concern about a resurgent epidemic of HIV-1 amongst men having sex with men in the Netherlands, which has parallels with similar epidemics now occurring in many other countries.

METHODS

A transmission model applicable to HIV-1 epidemics, including the use of antiretroviral therapy, is presented in a set of ordinary differential equations. The model is fitted by maximum likelihood to national HIV-1 and AIDS diagnosis data from 1980 to 2006, estimating parameters on average changes in unsafe sex and time to diagnosis. Robustness is studied with a detailed univariate sensitivity analysis, and a range of hypothetical scenarios are explored for the past and next decade.

RESULTS

With a reproduction number around the epidemic threshold one, the HIV-1 epidemic amongst men having sex with men in the Netherlands is still not under control. Scenario analysis showed that in the absence of antiretroviral therapy limiting infectiousness in treated patients, the epidemic could have been more than double its current size. Ninety percent of new HIV transmissions are estimated to take place before diagnosis of the index case. Decreasing time from infection to diagnosis, which was 2.5 years on average in 2006, can prevent many future infections.

CONCLUSIONS

Sexual risk behaviour amongst men having sex with men who are not aware of their infection is the most likely factor driving this epidemic.

The epidemiology of gonorrhea among men who have sex with men in Stockholm, Sweden, 1990-2004

OBJECTIVES

The objectives of this study were to analyze the spread of gonorrhea in men who have sex with men (MSM) in Stockholm regarding serovars, HIV status, and site of infection and to compare the distribution of serovars among HIV-positive and HIV-negative MSM.

STUDY DESIGN

Clinical and epidemiologic data were collected for all MSM diagnosed with gonorrhea in 1990 to 2004 at a clinic primarily serving MSM. Neisseria gonorrhoeae strains were serotyped.

RESULTS

A total of 1,039 isolates from 840 gonorrhea episodes in 721 patients were included. A sharp increase was seen during the 2000s. Ten percent of the cases were HIV-positive. The proportion of pharyngeal infections increased significantly (P <0.001) from 15% to 38% during the last 7 years. A great variation of serovars (n = 66) was observed, but only 5 were present >10 years. There was a significant difference (P = 0.001) in distribution of serovars correlated to HIV status.

CONCLUSION

Gonorrhea is a marker for HIV infection in MSM, but the increase in gonorrhea may be associated with genital-oral sexual practice rather than with high-risk sexual practice.

Decline in HIV incidence and injecting, but not in sexual risk behaviour, seen in drug users in Amsterdam: a 19-year prospective cohort study

OBJECTIVE

To study temporal changes in HIV incidence, HIV transmission routes, and both injecting and sexual risk behaviour in the open Amsterdam Cohort Study (ACS) among drug users. Initiated in 1985, the ACS enables us to study changes in trends since HAART became widespread in 1996.

METHODS

Person-time techniques were used to study the trend in HIV incidence among HIV-negative drug users. HIV transmission routes were determined using detailed standardised questionnaires. Trends in injecting and sexual risk behaviours were evaluated with a logistic regression model adjusted for correlations between visits of the same individual.

RESULTS

The 1315 HIV-negative individuals, of whom 93 seroconverted for HIV, yielded 6970 HIV-negative person-years of follow-up. The HIV incidence was seven per 100 person-years in 1986 and varied between 0 and 0.5 per 100 person-years after 1999. The odds ratio was 15.6 (95% confidence interval, 2.6-94.6) for HIV transmission through unprotected heterosexual contact versus injecting after 1996 compared with the period before. Reports of both injecting and borrowing needles significantly declined over the period 1985-2004. Reports of sexual risk behaviour and sexually transmitted infections at follow-up visits decreased before 1996, but not after 1996.

CONCLUSION

The HIV incidence among drug users in the ACS has declined since 1985. Accompanied by a reduction in injecting drug use and needle sharing, this decline occurred despite continued sexual risk behaviour. At present, new HIV seroconversions are related mainly to unprotected heterosexual contacts. Therefore, HIV prevention programmes for drug users should pay specific attention to the importance of safe sex practices.

Epidemiology of human immunodeficiency virus, viral hepatitis (B and C), treponema pallidum, and human T-cell lymphotropic I/II virus among men who have sex with men in Buenos Aires, Argentina

BACKGROUND

Human immunodeficiency virus (HIV) and sexually transmitted infections (STI) are prevalent among men who have sex with men (MSM).

GOAL

To estimate the prevalence of HIV and STIs in this group.

STUDY

A total of 694 MSM were tested for HIV, hepatitis B (HBV), hepatitis C (HCV), human T-cell lymphotropic (HTLV-I/II) viruses and Treponema pallidum infection.

RESULTS

HIV, HBV, and T pallidum were detected in 13.8%, 37.7%, and 16.9% of subjects, respectively. Prevalences of 1.9% and 0.3% were detected for HCV and HTLV-I/II. A prior history of STI was the most predictor for HIV, HBV, and T pallidum. Use of illegal drugs, blood transfusion history, and multiple sexual partners were associated with HCV. The 2 most common co-infections were HBV/T pallidum and HIV/HBV.

CONCLUSIONS

Infection with HIV, HBV, and T pallidum was elevated among MSM. Routine testing, education, vaccine-based prevention, and control programs need to be implemented in this high-risk population.

Incidence of sexually transmitted diseases and HIV infection in men who have sex with men related to knowledge, perceived susceptibility, and perceived severity of sexually transmitted diseases and HIV infection: Dutch MSM-Cohort Study

BACKGROUND

This longitudinal study was conducted to investigate whether knowledge, perceived susceptibility, and perceived severity of HIV infection and sexually transmitted diseases (STDs) are associated with the incidence of STDs and new HIV infections among men who have sex with men (MSM).

METHODS

A 3-year cohort study was conducted among 190 HIV-negative MSM. Data were collected on the incidence of STDs and new HIV infections, as well as on knowledge and perceived susceptibility to and perceived severity of HIV infection and STDs. Knowledge and perceptions were assessed in self-administered questionnaires.

RESULTS

In the course of the 3-year study, six MSM (3.2%) HIV-seroconverted and 78 (41.1%) participants were diagnosed with at least one STD. MSM seemed to be better informed about HIV infection compared with STDs, and HIV infection was perceived as more severe than other STDs. In multivariable analyses, low perceived severity of HIV infection significantly (P = 0.025) predicted increased likelihood of infection with STDs or HIV, and the practice of anal intercourse was (marginally) associated with an increased risk of acquiring STDs or HIV (P = 0.052).

CONCLUSIONS

A high perceived severity of HIV infection seems to induce sexual behavior that protects against STDs and HIV infection. More research is needed to establish the specific behaviors by which perceived severity of STDs/HIV influences the incidence of STDs and HIV.

The urban environment and sexual risk behavior among men who have sex with men

Increasingly, studies show that characteristics of the urban environment influence a wide variety of health behaviors and disease outcomes, yet few studies have focused on the sexual risk behaviors of men who have sex with men (MSM). This focus is important as many gay men reside in or move to urban areas, and sexual risk behaviors and associated outcomes have increased among some urban MSM in recent years. As interventions aimed at changing individual-level risk behaviors have shown mainly short-term effects, consideration of broader environmental influences is needed. Previous efforts to assess the influence of environmental characteristics on sexual behaviors and related health outcomes among the general population have generally applied three theories as explanatory models: physical disorder, social disorganization and social norms theories. In these models, the intervening mechanisms specified to link environmental characteristics to individual-level outcomes include stress, collective efficacy, and social influence processes, respectively. Whether these models can be empirically supported in generating inferences about the sexual behavior of urban MSM is underdeveloped. Conceptualizing sexual risk among MSM to include social and physical environmental characteristics provides a basis for generating novel and holistic disease prevention and health promotion interventions.

Understanding recent increases in the incidence of sexually transmitted infections in men having sex with men: changes in risk behavior from risk avoidance to risk reduction

OBJECTIVE

The objective of this study was to explore risk behavior and routes of transmission in men having sex with men (MSM) with newly diagnosed sexually transmitted infections (STIs).

METHODS

A questionnaire on clinical diagnosis and manifestation site for acute STIs was completed by physicians participating in a sentinel study. Patients contributed information on sexual risk behavior and the likely route of STI transmission.

RESULTS

Three hundred fifty-six diagnosis forms and 169 matching patient questionnaires could be analyzed. The most frequent diagnosis was syphilis (n = 147; 33% primary syphilis with ulcer localization 71% genital, 22% anorectal, and 8% oral; 67% secondary syphilis), followed by gonorrhea (n = 136; 59% genital, 34% rectal, 7% pharyngeal) and Chlamydia trachomatis infection (n = 51; 48% genital, 48% rectal, 4% pharyngeal). In 12 patients, more than one infection was diagnosed, and 2 or 3 sites were affected in 11 patients. Approximately 60% of infections were acquired by genital-oral and oral-anal practices. Unprotected anal intercourse (UAI) was reported more often by HIV-positive men (mostly receptive) and men with high partner numbers.

CONCLUSION

High partner numbers, an important role of genital-oral sexual practices for the transmission of STIs, and relatively high frequencies of mostly receptive UAI in HIV-positive men are all contributing to increasing STI incidences among MSM.

Crystal methamphetamine and ecstasy differ in relation to unsafe sex among young gay men

OBJECTIVE

Poly-substance use in gay social ('club') settings is common. Recent studies suggest a link between 'club' drug use and sexual risk behaviours. In this qualitative study, we compare and contrast two 'club' drugs: crystal methamphetamine and ecstasy (MDMA).

METHODS

Life history interviews were conducted with 12 HIV seroconverters and 12 age-matched controls recruited from a prospective cohort study of young gay and bisexual men in Vancouver, British Columbia. Textual data concerning illicit substance use and unsafe sex were analyzed using NUDIST software.

RESULTS

Most men related a substantial knowledge of and experience with crystal and ecstasy. Both drugs had attributes that enhanced gay socialization and were used in the same venues. Crystal was used to remain awake and increase energy. Ecstasy was used to induce euphoria and group connectedness. However, unlike ecstasy, crystal was associated with a distinct pattern of sexual arousal that frequently included unprotected (sometimes group) sex, was more likely to be used regularly by HIV-positive men, and was reportedly highly addictive and problematic.

CONCLUSION

Crystal and ecstasy are used in the same social venues but differ markedly in relation to sexual risk behaviour.

High-risk sexual behaviour among London gay men: no longer increasing

Among gay men surveyed annually in central London gyms, the percentage reporting high-risk sexual behaviour with a casual partner increased from 6.7% in 1998 to 15.2% in 2001 (P < 0.001). However, between 2002 and 2005 the percentage reporting high-risk sexual behaviour with a casual partner remained stable for HIV-negative and never-tested men (P > or = 0.3), with some evidence of a decline for HIV-positive men (adjusted odds ratio 0.69 per year, 95% confidence interval 0.48, 0.99, P = 0.047).

Florida’s Multifaceted Response for Increases in Syphilis Among MSM: The Miami–Ft. Lauderdale Initiative

After many years of declining rates, it became apparent in 1999 that syphilis cases were on the rise in Florida. Data analysis identified that the outbreak was predominately contained in Miami and Ft. Lauderdale and among men who have sex with men. An in-depth investigation was undertaken to identify the risk factors, the best way to attack the outbreak, and how to build sustainability into implemented strategies. After thorough review of the data and extensive dialogue with local public health and community participants, the Bureau of STD Prevention & Control developed initiatives that focused public awareness through print, radio, and television media resources; expanded access to men's health services; and enhanced education/training for public and private health care providers, STD program field staff, and community representatives. This initiative has resulted in unprecedented community involvement in syphilis control efforts.

The impact of the transmission dynamics of the HIV/AIDS epidemic on sexual behaviour: a new hypothesis to explain recent increases in risk taking-behaviour among men who have sex with men

Increases in sexually transmitted infections and related high-risk behaviours have been reported among men who have sex with men (MSM) in industrialised countries when effective antiretroviral therapy against HIV infection has become widely available, in the mid-nineties. The reasons for these increases are not fully understood and often conflicting. Prevention fatigue, relapses to unsafe sex, as well as optimism toward the risk of developing AIDS among people living with HIV are not unique to the era of antiretroviral therapy (ART). This has led researchers to highlight the need to investigate other potential reasons that could explain the increase in high-risk taking following the ART introduction. We put forward the hypothesis that the change in the transmission dynamics of the HIV/AIDS epidemic before and after the introduction of ART has contributed to this change in high-risk behaviour. It is suggested that a decline in sexual risk activities has occurred at the population-level following the initial spread of the HIV/AIDS epidemic because AIDS mortality and severe morbidity disproportionately depleted the pool of high-risk taking individuals. As a result, non-volitional changes may have occurred at the individual-level over time because the depletion of this pool of high-risk individuals made it more difficult for the remaining high-risk taking individuals to find partners to engage in risky sex with. Following its introduction, ART has facilitated the differential replenishment of the pool of individuals willing to engage in high-risk taking behaviours because ART reduces AIDS mortality, and morbidity. Consequently, high-risk taking individuals who had previously reduced their level of risky sex non-volitionally (i.e., as a result of the reduced availability of high-risk partners) were able to resume their initial high-risk practices as the pool of high-risk taking individuals replenished over time. Thus, a fraction of the recently reported increase in high-risk sexual activities may be secondary to the fact that those MSM who were unable to engage in their desired high-risky sexual activities (because of reduced availability) are now able to revert to them as the availability of men willing to engage in risky sexual behaviours increases partly due to ART. Therefore, we suggest that a fraction of the changes in individual behaviour are non-volitional and can be explained by a change in "sexual partner availability" due to the transmission dynamics of HIV/AIDS before and after ART. The hypothesis is formulated and explained using simple social network diagrams and the Theory of Planned Behaviour. We also discuss the implication of this hypothesis for HIV prevention.

Unprotected anal intercourse among HIV-positive men who have a steady male sex partner with negative or unknown HIV serostatus

OBJECTIVES

We sought to determine the prevalence and predictors of unprotected anal intercourse (UAI) among HIV-positive men who have a single steady male partner with negative or unknown HIV serostatus.

METHODS

We analyzed behavioral surveillance data from HIV-positive men who have sex with men (MSM) interviewed in 12 states between 1995 and 2000.

RESULTS

Of 970 HIV-positive MSM who had a single steady male sex partner with negative or unknown serostatus, 278 (29%) reported UAI during the previous year. In a subset of 674 men who were aware of their infection, 144 (21%) had UAI. Among the men who were aware of their infection, factors found to be predictive of UAI in multivariate modeling were heterosexual self-identification, crack cocaine use, no education beyond high school, and a partner with unknown serostatus.

CONCLUSIONS

Even after learning of their infection, one fifth of HIV-positive MSM who had a single steady male partner with negative or unknown serostatus engaged in UAI, underscoring the need to expand HIV prevention interventions among these men.

Declining trend in transmission of drug-resistant HIV-1 in Amsterdam

OBJECTIVE

Symptomatic primary HIV infections are over-represented in the mainly hospital-based studies on transmission of resistant HIV-1. We examined a more general population for the prevalence of resistant HIV-1 strains among primary infections.

DESIGN

From 1994 to 2002 primary infections were identified within the Amsterdam Cohort Studies (ACS) among homosexual men and drug users, and at the Academic Medical Center (AMC). Whereas primary HIV-1-infected AMC patients, often presented with symptoms of acute retroviral syndrome, ACS participants largely seroconverted during follow-up and thus brought also asymptomatic primary infections to our study.

METHODS

Reverse transcriptase (RT) and protease sequences were obtained by population-based nucleotide sequence analysis of the first HIV RNA-positive sample available. Subtypes were identified by phylogenetic analysis. Mutations were identified based on the IAS-USA resistance table.

RESULTS

A total of 100 primary HIV-1 infections were identified (32 AMC and 68 ACS). Transmission of drug-resistant strains decreased over calendar time, with 20% [95% confidence interval (CI), 10-34%] of infections bearing drug-resistant mutations before 1998 versus only 6% (95% CI, 1-17%) after 1998. No multi-drug resistance pattern was observed. The median plasma HIV-1 RNA level of the first RNA positive sample was significantly lower for the individuals infected with a resistant strain versus those infected with wild-type, suggesting a fitness-cost to resistance. Four of seven non-B subtypes corresponded with the prevalent subtype in the presumed country of infection, and none showed resistance mutations.

CONCLUSIONS

The transmission of drug-resistant HIV-1 strains in Amsterdam has decreased over time. Monitoring should be continued as this trend might change.

Changes in the transmission dynamics of the HIV epidemic after the wide-scale use of antiretroviral therapy could explain increases in sexually transmitted infections: results from mathematical models

BACKGROUND

Recent increases in bacterial sexually transmitted infections (STI) and risk behavior have coincided with the introduction of antiretroviral therapy (ART) in homosexual communities of industrialized countries. The reasons for these increases are not fully understood.

GOAL

The goal of this study was to understand the various effects of ART on risk behaviors and STI.

OBJECTIVE

The objective of this study was to assess the independent impact of the change in the transmission dynamics of HIV/AIDS as a result of the wide-scale use of ART on a bacterial STI.

STUDY DESIGN

We developed a mathematical model of bacterial STI and treated/untreated HIV/AIDS infection for an open homosexual population. At the individual level, we assume that susceptible and healthy HIV-positive individuals do not increase their risk behavior as a result of ART over time. However, individuals with AIDS, who are successfully treated with ART, can resume sexual activity. The impact of the wide-scale use of ART on risky behavior, STI, and HIV/AIDS was evaluated over a wide range of assumptions on treatment use, ART efficacy, and population characteristics.

RESULTS

Over 10 years, 0% to 55% new bacterial STI could be attributed to the wide-scale use of ART as a result of more modest increases (0-25%) in risky sex occurring at the population level rather than at the individual level. These increases have a negative impact on HIV if coverage is too low. Increasing treatment coverage helps to prevent more HIV infections despite larger increases in risky sex and STI that is predicted to ensue.

CONCLUSION

Taking the differential impact of wide-scale use of ART into account helps to interpret recent behavioral and STI trends. Our results have implications for prevention strategies and for the formulation of public health policies. A better understanding of the differential impact of ART on sexual network over time is required.

HIV incidence on the increase among homosexual men attending an Amsterdam sexually transmitted disease clinic: using a novel approach for detecting recent infections

OBJECTIVE

Dramatic increases have occurred in sexually transmitted diseases (STD) and in sexual risk behaviour among homosexual men in Amsterdam and internationally. We investigated whether these trends indicate a resurgence of the HIV epidemic.

METHODS

HIV incidence was determined among homosexual attendees of an STD clinic in Amsterdam, who had participated in semi-annual anonymous unlinked cross-sectional HIV prevalence studies from 1991 to 2001. Stored HIV-seropositive samples were tested with a less-sensitive HIV assay and, if non-reactive, were further tested for the presence of antiretroviral drugs, indicative of the use of highly active antiretroviral therapy. Seropositive men who tested non-reactive on the less-sensitive assay and had not used antiretroviral drugs were classified as recently infected (< 170 days). Annual HIV incidence and its changes were examined.

RESULTS

Among 3090 homosexual participants (median age 34 years), 454 were HIV infected, of whom 37 were recently infectioned. From 1991 to 2001 the overall incidence was 3.0 infections/100 person-years. Incidence increased over time (P = 0.02) and, strikingly, the increase was evident in older (> or = 34 years) men (P < 0.01), but not in the young. Of men recently infected, 84% (n = 31) were unaware of their infection and 70.3% (n = 26) had a concurrent STD. These 26 men reportedly had sex with a total of 315 men in the preceding 6 months.

CONCLUSION

HIV incidence is increasing among homosexual attendees of an STD clinic. It is imperative to trace recently infected individuals, because they are highly infectious, and can thus play a key role in the spread of HIV.