No abstract

National Institute for Health Research.

BackgroundThere 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.MethodsWe 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.ResultsHIV-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.ConclusionA 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.

The aim of this paper is to advance rigorous Internet-based HIV/STD Prevention quantitative research by providing guidance to fellow researchers, faculty supervising graduates, human subjects' committees, and review groups about some of the most common and challenging questions about Internet-based HIV prevention quantitative research. The authors represent several research groups who have gained experience conducting some of the first Internet-based HIV/STD prevention quantitative surveys in the US and elsewhere. Sixteen questions specific to Internet-based HIV prevention survey research are identified. To aid rigorous development and review of applications, these questions are organized around six common criteria used in federal review groups in the US: significance, innovation, approach (broken down further by research design, formative development, procedures, sampling considerations, and data collection); investigator, environment and human subjects' issues. Strategies promoting minority participant recruitment, minimizing attrition, validating participants, and compensating participants are discussed. Throughout, the implications on budget and realistic timetabling are identified.

The review reminds us of the complexity of human and sexual behaviour. Among gay men, sexual behaviour in the era of highly active antiretroviral therapy has been characterized by risk reduction and stabilization as well as increasing risk. These changing patterns provide a new challenge as well as new opportunities for HIV prevention.

There was a high prevalence of polydrug use and chemsex drug use among HIV negative MSM attending UK sexual health clinics. Drug use was strongly associated with sexual behaviours linked to risk of acquisition of STIs and HIV.

Seeking sex on the Internet was associated with recent STD and high-risk sexual behaviour among HIV-positive and -negative gay men in London. The contribution of seeking sex on the Internet to the recent increase in high-risk behaviour among London gay men merits further investigation.

Among London gay men, no difference was detected between those who were optimistic and those who were not in the rate of increase in high-risk sexual behaviour between 1998 and 2001. Our findings suggest that HIV optimism is unlikely to explain the recent increase in high-risk sexual behaviour in these men.