Introduction

HIV has become a pandemic because it has a lethal combination of properties:

• transmission via that most taboo, intractable and instinctive of human activities, sex,
• a long asymptomatic incubation period during which people are healthy, sexually active - and infectious,
• the fact that it hijacks the immune responses that the body normally mounts to contain disease to serve as the fertile soil for its growth,
• that, as a retrovirus, it splices its genes into our own, so effectively merging its identity with ours so that it stays in the body for life.

Changing sexual behaviour involves revolutionising cultural attitudes, confronting taboos, reaching out to the most marginalised and despised populations and including them in dialogue, and helping people make rational decisions about their health at the very moments when they are least rational.

HIV prevention can include a myriad of activities, but falls into six broad classes:

• Biomedical approaches include circumcision, microbicides, vaccines, pre-exposure prophylaxis (PrEP), post-exposure prophylaxis (PEP) and needle exchange. Barrier methods like condoms are biomedical, though programmes to ensure their use are not.  HIV treatment can be considered a prevention measure because antiretrovirals reduce people’s infectiousness.
• Individual approaches include one-to-one counselling (including voluntary counselling and testing), cognitive behavioural therapy, face-to-face detached or outreach work, telephone helplines and certain internet interventions.
• Group approaches are those delivered to small groups of individuals, often from the same peer group, and they are usually facilitated in some way. They include school sex education and small-group work that usually includes both information and risk reduction skills training.
• Community interventions are delivered to the whole population or (more frequently) a target audience; the difference from the previous interventions being that individuals do not need to seek out the programme. They include media stories and small-media resources (e.g. leaflets and posters), condom distribution schemes, and some internet interventions like chat rooms.
• Structural interventions which address the drivers of vulnerability such as gender inequality, economic inequality, and lack of social capital.
• Sociopolitical interventions include legal change such as the decriminalisation of homosexuality or intravenous drug use; legal sanctions such as the criminalisation of transmission; and policy interventions which may permit other types of prevention work, such as allowing needle exchange.

Medical specialists may be of the view that only biomedical interventions such as treatment and vaccines can ever have an effect on HIV. It is true that many pandemics in the past, such as polio and smallpox, have been defeated when a vaccine has been developed. However those for which we have struggled to find a prophylaxis, such as TB and malaria, are still very much with us. But this is to ignore firstly the effect of treatment – which has reduced the death rate due to previously dreaded diseases like syphilis to near-zero in the developed world – and secondly, the powerful effect that correctly timed and targeted public health interventions can have. To give one example, it is estimated that there would be twice as many people living with HIV in Thailand today had it not been for that country’s ‘100% condom campaign’ (Malcolm 1998) in the early 1990s.

Such dramatic reductions in HIV incidence and prevalence are quite rare, however. Prevention success in HIV is more often a gradual and incremental process, involving gradual behaviour change as well as underlying epidemiological processes such as attrition due to AIDS. The largest meta-review of behavioural HIV interventions ever conducted (Albarracin 2005) only measured condom use but found that ‘active’ interventions (getting people to practise skills) increased condom use by 38% relative to baseline and passive ones (where people just watched or listened to training) by 16%. Because baseline condom use was 32.3% this means that there was only an absolute increase in people who ‘always’ used condoms by 7.8% and a decrease in people who ‘never’ used them of 17% (for other meta-analyses of the effectiveness of prevention programmes, see Behaviour change - what methods work?).

This may not sound like a great reduction. But no public health intervention is ever 100% successful. In addition, public health measures may take decades to have an effect. For instance, in the USA, the proportion of driving deaths caused by drunk drivers declined from 57% in 1982 to 45% in 1992. This 10% reduction was considered a major victory for public awareness campaigning and legal changes.

One paper (Stryker 1995) put it this way: “Given experience in other health behaviour change endeavours, nointerventions are likely to reduce the incidence of HIV infection to zero;indeed, insisting on too high a standard for HIV risk-reduction programsmay actually undermine their effectiveness.”

In the absence of the basic scientific discoveries that are needed before an HIV vaccine can be envisaged, no single intervention covered in this book, already in use or for the future, is likely to turn the tide of the epidemic in itself. Instead of a ‘magic bullet’ that would send HIV the way of smallpox, the job of HIV prevention researchers, advocates and practitioners is therefore to maximise choice: to provide people with and at risk of HIV with as many tools as possible to prevent them transmitting or acquiring the virus and the power to use those tools.