40% of gay men with HIV don't know they are infected

A survey of gay men questioned at gay venues in cities across the UK has found that most of those with undiagnosed HIV infection assumed they were HIV negative. Most of them had previously tested negative and thought they were in the clear. It's feared these men could unknowingly be putting others at risk. These are the findings of a study led by Dr Lisa Williamson at the MRC Social and Public Health Sciences Unit in Glasgow and published in the journal, AIDS.

The surveys were carried out in Glasgow and Edinburgh by the MRC, and in London, Brighton and Manchester by the UCL Centre for Sexual Health and HIV Research.

3,500 gay men were questioned. They provided oral fluid samples to be tested anonymously for HIV antibodies. Nine per cent were HIV-positive but just under half of them did not realise.

The study also found that risky sexual behaviour was more common among men who were aware of their HIV-positive status than among men who were undiagnosed or HIV negative; even more so in those who had been HIV positive longest.

Dr Williamson said: "Our study shows a clear need for a re-invigorated and targeted approach to HIV prevention among gay men in the UK. We need to promote condom use and risk reduction strategies even in men who are regularly tested. The results suggest that reducing the number of gay men with undiagnosed HIV infection may not in itself be enough to reduce new infections among gay men. GUM clinics should offer HIV testing and risk reduction advice to all gay men presenting as well as offering repeat testing at men who are found to be HIV-negative but report high risk behaviours. We need to re-double our efforts to help men avoid risky sexual behaviour. And, most importantly, we need to target men living with HIV as well as those testing negative."

Dr Williamson added: "Maintaining safe sex practices long-term may be what men are finding difficult. Although some men could be taking steps to reduce the risk of HIV transmission, one in three men with diagnosed HIV reported having unprotected anal sex with a partner whose HIV status was unknown or different to their own."

Williamson, LM et al. Sexual risk behaviour and knowledge of HIV status among community samples of gay men in the UK. AIDS 22(9): 1063-1070, 2008.