Epidemiologists use the phrase `risk groups' to refer to people who may be vulnerable to a particular medical or social condition. For example, smokers are a risk group for lung cancer and need specially targeted health education. Or, for example, an outbreak of meningitis in Gloucestershire means that people who live there constitute a risk group with special needs. So the idea of risk groups is useful for identifying the need for particular resources and services.

While everyone is biologically susceptible to infection with HIV if exposed to the virus, this does not mean that everyone is equally at risk from the virus. For example, a gay man having unsafe sex is at much greater risk of becoming infected with HIV than a heterosexual man having unsafe sex. This is for the simple reason that in Britain to date, HIV has disproportionately affected certain definable groups within the population, namely gay men and injecting drug users. In some parts of the country up to one in five gay men may be HIV–positive. Gay men are thus far more likely to encounter sexual partners who have HIV than are most heterosexuals.

To this extent, definable groups within the population may be accurately described as high-risk groups, because they are at the greatest statistical risk of being or becoming HIV–positive through unsafe sex. This recognition should be seen as benign, rather than stigmatising or hostile, since it allows priorities in HIV education and care service provision to be established. In a world of limited resources, it makes sense that resources are targeted to the areas of greatest need.

Unfortunately, this benign concept has been misused throughout the epidemic. The identification of gay men and injecting drug users as high-risk groups in the early 1980s did not result in education and care services being targeted to them; indeed, it was left largely to underfunded voluntary groups to `look after their own'. Instead, members of the high-risk groups were falsely believed to be a risk to others, rather than to be at increased risk themselves. Gay men and drug users were consequently targeted with hysterical blame, prejudice and discrimination.

The misunderstanding of `high-risk groups' also contributed to the idea of bridging groups, and the related idea that HIV spreads from gay men through bisexual men and hence to women and thus the general public.

Because of these phenomena, AIDS educators in the 1980s went to considerable lengths to discourage the use of the high risk group terminology. But now, with the advantage of hindsight, it is clear that the rejection of the concept may have done more harm than good.

AIDS education which stressed that everyone was potentially at risk from HIV has been widely misunderstood as meaning that everyone is equally at risk. Consequently, HIV prevention work in the 1980s was generally characterised by vague and untargeted campaigns for the `general population', and initiatives focusing on those most at risk were almost entirely neglected.

The harmful consequences have been twofold. First, non-drug–using heterosexuals have realised that they are not at such great risk of HIV infection as many campaigns indicated, and appear now to distrust any AIDS education that is directed to them. Secondly, safer sex campaigns for gay men have been neglected. This is likely to be one of the reasons why increases in unsafe sex and in new HIV infections have been reported among gay men since the late 1980s.

In the UK, the bridge communities of bisexual men and injection drug users have failed to have a great impact on the spread of HIV into the general population through heterosexual sex.

In 1990 2.6% of the total diagnosed with HIV in the UK, 12.3% of diagnosed heterosexuals, and approximately 40% of heterosexuals who had acquired their HIV in the UK, were heterosexuals who had acquired HIV from an injecting drug user or (known) bisexual man. By 2004 that proportion had gone down to 0.5% of total infections, 0.9% of heterosexual infections, and no more than 7% of infections acquired by heterosexuals within the UK.

While ‘bridges’ between risk groups may be important in other situations (for instance, between married men who have sex with men and their wives in certain developing countries), in the UK it appears that there are discrete epidemics within each risk group.

Reference

Anderson R. Trends in HIV incidence and prevalence: natural course of the epidemic or results of behavioural change? UNAIDS, 1999. See http://www.emro.who.int/asd/backgrounddocuments/uae03/surv/trends%20in%20HIV%20incidence%20and%20prevalence.pdf