The importance of targeting

An editorial in the New England Journal of Medicine summarised current thinking amongst epidemiologists and public health planners on the value of targeting.

The argument for targeting HIV prevention is based on the marked difference in rates of HIV infection and AIDS amongst those engaging in various types of high-risk behaviour, living in various areas, and belonging to various demographic groups.

Publicly emphasising that large numbers of people are at low, but not at zero risk, has potentially serious political consequences. People are not very good at processing information about low–probability events in which there could be a highly negative outcome. They tend to greatly over–estimate or under–estimate the likelihood of such events, and their estimates can be unduly influenced by small amounts of new information.

Public emphasis on the low but not quite zero risk of HIV infection may thus lead many people to overestimate their chances of becoming infected. If later information, including personal experience, contradicts these exaggerated fears, people are likely to revert to their previous underestimation of risk.

In addition, they may conclude that their fear of HIV infection was deliberately manipulated by health officials, AIDS activists and researchers to advance other agendas.

An effective programme to prevent HIV infection must have both universal and targeted components. The universal component includes reducing HIV–related discrimination, removing commercial restrictions on the materials necessary for safer behaviour, and providing information about the risk of HIV transmission. The targeted component involves focusing the limited resources for intensive programmes of behavioral change on situations in which the risk of HIV transmission is highest. Such a strategy would follow the dictum of `Warn widely and spend wisely' (Des Jarlais).

`Targeting' is a term loosely used in HIV prevention, often without a clear understanding of what it implies. In fact, `targeting' refers to a chain of decisions made in HIV prevention work. It refers to:

• The assessment of local need (ideally with reference to national and local epidemiological data).
• The recognition of particular risk groups/needs.
• The decision to allocate resources to meet particular needs (prioritisation).
• The development of strategies to address the target group.
• The evaluation of the impact of targeted work.
• The adjustment of strategy to take into account the results of evaluation and the impact of targeted work on epidemiological trends.

See also: HIV prevention: which methods work?.