London, Brighton, Manchester: many gay men with undiagnosed HIV and high levels of risky sex

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A study conducted in gay commercial venues in three UK cities with a large gay population has found that many HIV infections remain undiagnosed, and that many men are engaging in sexual activity that involves a real risk of HIV transmission. The study is published in the May 1st (online) edition of Sexually Transmitted Infections, and was conducted between 2003 and 2004, involving men recruited in London, Manchester and Brighton. Its findings are remarkably similar to those of the 2005 Gay Men’s Sex Survey.

HIV transmission amongst gay men continues to occur in the United Kingdom, with many infections remaining undiagnosed. Investigators wished to establish if there were differences between London, Manchester and Brighton, cities with the largest concentrations of gay men in the UK, in terms of diagnosed and undiagnosed HIV, use of sexual health clinics, recent sexually transmitted infections, and unprotected anal sex.

Men participating in the study were asked to complete a questionnaire and to undergo an oral HIV test. The men were recruited in bars, clubs and saunas. The investigators stress that the study population was therefore a ‘convenience sample’ and that “data from convenience sampling are likely to overestimate the prevalence of sexual risk behaviour and sexual health outcomes for all men who have sex with men in Britain.”



Refers to the mouth, for example a medicine taken by mouth.


Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

risky behaviour

In HIV, refers to any behaviour or action that increases an individual’s probability of acquiring or transmitting HIV, such as having unprotected sex, having multiple partners or sharing drug injection equipment.


Social attitudes that suggest that having a particular illness or being in a particular situation is something to be ashamed of. Stigma can be questioned and challenged.

statistical significance

Statistical tests are used to judge whether the results of a study could be due to chance and would not be confirmed if the study was repeated. If result is probably not due to chance, the results are ‘statistically significant’. 

Oral HIV testing revealed that 12% of gay men in London were HIV-positive, compared to 14% in Brighton and 9% in Manchester. These differences were not, however, statistically significant.

The investigators found that 30% of men in London identified as HIV-positive using the oral test did not know that they had HIV, even though they had visited a sexual health clinic in the last year. In Brighton, 28% of HIV infections were undiagnosed amongst sexual health clinic attendees, as were 19% of infections amongst men who had visited a clinic in Manchester.

Most HIV infections amongst gay men who had not been to a sexual health clinic was undiagnosed (70% in London; 55% in Brighton; 78% in Manchester).

Only 61% of HIV-negative men in Brighton reported an HIV test in the last five years, compared to 63% of men in Brighton and 68% of the London sample.

A sexually transmitted infection in the last year was reported by 20% of HIV-negative men across the three cities, this compared to between a third and 50% of HIV-positive men.

Overall, 22% of HIV-negative men reported unprotected anal sex with a man who was either HIV-positive or of unknown HIV status in the last year. There was no significant difference between the three cities in the study (21% in London; 24% in Brighton; 22% in Manchester).

The investigators also found that 30% of HIV-positive men had had unprotected anal sex with men who were either HIV-negative or of unknown HIV status. Once again, there was no significant difference between the study cities (28% in London; 34% in Brighton; 31% in Manchester).

“Voluntary confidential HIV testing should be promoted in all three cities to reduce the proportion of men undiagnosed”, write the investigators, adding, “barriers to testing, including poor access to GUM clinics, and the stigma associated with HIV must be addressed.”

“The high levels of HIV prevalence and risk behaviour in all three cities indicate a need for more effective HIV prevention”, conclude the authors. The similarity of findings for the three cities in the study suggests to the investigators that “the same HIV risk profile for men who have sex with men is applicable in all three…which is useful when considering intervention designs for these cities.”


Dodds JP et al. A tale of three cities: persisting high HIV prevalence, risk behaviour and undiagnosed infection in community samples of men who have sex with men. Sex Transm Infect (online edition), 2007.