An estimated 32,000 gay men were living with HIV in the UK in 2007 and almost a quarter were unaware of their infection, according to figures released today by the Health Protection Agency.

There were an estimated 3,160 new HIV diagnoses among gay men in 2007, showing that numbers of new diagnoses are at their highest level ever since the mid 1980s.

Nearly 500 men (499) were diagnosed after the point at which treatment should have begun, meaning they missed out on the benefits associated with early diagnosis including prolonged life expectancy.

Early diagnosis continues to be the most important factor in mortality and morbidity linked to HIV.

It is also an important factor in the interruption of HIV transmission within the community.

Analysis of figures over the past five years has shown that a late diagnosis of HIV meant that gay men were 13 times more likely to die within one year of diagnosis compared to those diagnosed early.

Dr Valerie Delpech, Head of HIV surveillance at the Health Protection Agency’s Centre for Infections, said:

“The HIV epidemic continues to have the greatest impact in gay men in the UK with the number of new HIV diagnoses at levels not reported since the mid 1980s.

“With a worryingly high proportion of men unaware of their HIV status and high levels of late HIV diagnoses, gay men need to test annually for HIV as early diagnosis can increase an individual’s life expectancy.”

In 2007, a high proportion of gay men diagnosed with an acute sexually transmitted infection, such as syphilis, were also HIV positive.

Latest figures on gay men attending genitourinary medicine (GUM) clinics show that 40% of syphilis, 32% of gonorrhoea, 78% of lymphogranuloma venereum (LGV) and 97% of Hepatitis C cases were also HIV positive.

To reduce HIV transmission among gay men is not just about encouraging men to have an annual sexual health check and HIV test, but also about changing behaviour,” said Dr Delpech.

“The high levels of men diagnosed with an acute STI who are also co-infected with HIV demonstrate the dangers of serosorting.

“Serosorting is not safe sex. There are about 8,000 HIV-infected gay men who are unaware of their HIV infection and who may believe themselves to be negative – they may unknowingly transmit the virus to their partners.

“For HIV-positive men, serosorting can mean acquiring an STI which makes the treatment of both infections more difficult. Men should use a condom with all new partners until both have been screened for HIV and STIs. Men should always use a condom when having sex with casual partners.”

The National AIDS Trust said the increase in diagnoses is likely to be because more gay men are getting tested for HIV.

Testing in sexual health clinics has increased, with 86 per cent of gay men offered a test in sexual health clinics accepting compared to 84 per cent in 2006. The proportion of gay men unaware of their HIV infection has declined to 1 in 4 – compared with 1 in 3 previously.

Young gay men (under 25) are more likely to accept a HIV test compared with older gay men, 92% of under 25s accepted a test in a sexual health clinic in 2007 compared to 84 per cent of older gay men.

Deborah Jack, Chief Executive of NAT (National AIDS Trust), said:

“We are seeing positive signs over recent years as slowly the messages about the importance of having HIV tests are getting through and more gay men are getting tested. Especially heartening is that young gay men are coming forward for tests.

“This testing culture among young men new on the scene needs to expand to older gay men who are most at risk from HIV.

“Given the record number of diagnoses we are seeing each year, the message remains HIV must be something that all gay men think about. Every gay man should get tested at least once a year.”

Sexual health charity Terrence Higgins Trust said:

“Many gay men who’ve had unprotected sex assume they’re still HIV negative but thousands who make that assumption are mistaken. A quarter of gay men with HIV don’t know they have it so it’s a dangerous mistake to make.

“We’ve just launched a major new awareness campaign for gay men, “THIVK you’re negative?”, and we and our partner organisations are going out into gay venues across the country to get the message across. ”

Click here for the full report from the Health Protection Agency.