But aren’t more heterosexual people diagnosed each year with HIV in the UK than gay men?

Health Protection Agency statistics show that there were 7,734 new HIV diagnoses in the UK in 2007. Fifty five percent (4,260) of these new diagnoses were among people who probably acquired HIV through heterosexual sex. However, of all of those heterosexual diagnoses, where a likely country of infection was reported 77% of them were probably infected outside the UK.

In contrast, over 80% of the MSM who were diagnosed with HIV in 2007 probably acquired HIV within the UK. That means that MSM account for two thirds of UK acquired HIV infection diagnosed in 2007, and diagnoses amongst MSM are the highest they have ever been since the emergence of the HIV epidemic in the UK 25 years ago. This makes MSM the group at by far the highest risk of new HIV infection in the UK today.

Although there are more heterosexual people living with HIV in the UK, the fact that the vast majority of them probably acquired HIV overseas has important implications for theway donated blood is screened for HIV. The best available evidence currently shows that heterosexual infection is statistically more likely to have taken place outside the UK, and that the majority of these people are not recently infected and are therefore outside the “window period”. This means that their HIV infection will be more likely to show up using the current screening methods available to the National Blood Service.