6.4 Behavioural data collection in a generalised epidemic

Groups with particularly high levels of risk behaviour may continue to drive new infections in a generalised epidemic, but the pattern of HIV spread goes far beyond higher-risk individuals and their immediate partners. By the time an epidemic becomes generalised, it is usually clear what the major risk behaviours are. Systematic and repeated behavioural data collection in the general population is essential for explaining changes in prevalence and tracking changes in behaviour over time. It must also focus on identifying the risk behaviours that have been neglected or have failed to respond to prevention efforts. New qualitative research may choose to explore the social, economic, and cultural context that determines who continues to be vulnerable to HIV infection and why.

Behavioural monitoring: populations with higher-risk behaviours

While it is important in a generalised epidemic to expand prevention efforts to those with somewhat lower risk of transmitting the virus, national programmes should not lose sight of groups that are driving the epidemic. Population groups practising high levels of risk behaviour still have a great impact on the spread of HIV infection in generalised epidemics. That is why it is essential to maintain a focus on interventions with those groups and, as a logical consequence, to monitor their behavioural trends.

In every generalised epidemic to date, the overwhelming risk factor for HIV infection has been unprotected sex with a partner of the opposite sex. While other groups, such as drug injectors or men who have sex with men, may also be at elevated risk, they have not historically contributed greatly to generalised epidemics. In this context, it is recommended that surveys concentrate their resources on tracking the behaviour of sex workers and any subgroups of the general population (for example, seasonal migrant workers) that interact extensively with sex workers but that may be missed in household surveys. Targeted surveys in these groups should be carried out every year or every other year, depending on available resources.

Behavioural monitoring: general population

Regular surveys of behaviour in the general population are critical in explaining the progress of HIV infection at the generalised stage of the epidemic. They are also a suitable tool for judging the overall success of the national response in supporting the adoption of safer behaviours. Because behaviours at the general population level tend to change more slowly, it is recommended that these surveys be carried out every four to five years.

Sampling for the general population survey should be coordinated with the key sites in the sentinel HIV serosurveillance system. This will make it possible to analyse behavioural trend data in conjunction with HIV prevalence data in antenatal clinic attenders from the same catchment area. Analysis of these data by age group (if possible by single year of age in the younger age groups) will enable evaluators to make a better informed interpretation of observed changes in HIV prevalence.

Because general population data are important to understanding a generalised epidemic, it is recommended that (in some instances where it might be feasible) household surveys collect data on HIV serostatus as well as behaviour. Saliva or blood specimens may be collected in households when interviews are conducted or separately in ad hoc clinics in association with clinical examination and treatment for specific diseases, including STDs. Informed consent and pre- and post-test counseling are prerequisites for this type of survey. Ethical guidance ensuring confidentiality and informed consent is needed.

Table 6: BEHAVIOURAL DATA NEEDS AND METHODS IN A GENERALISED EPIDEMIC

*DURATION: includes all research or survey stages from preparatory work to the production of findings.

Behavioural monitoring: young people

In generalised epidemics, the importance of behavioural patterns adopted in youth is greater than ever in determining the course of the HIV epidemic. As an epidemic matures and prevalence rises, most people exposed to HIV through their own or a partner's risk behaviour will already be infected. New infections are therefore concentrated in young people who have only recently become sexually active.

The positive side of this equation is that young people are more likely to adopt safe behaviour from the start of their sexual lives than are older people with already entrenched habits. In some countries, the only groups reporting substantial changes in behaviour in response to the epidemic are young people. And in those countries, youth are also the group in which HIV prevalence is falling most markedly.

In general, young people's behaviour should be studied in a household-based survey, supplemented by surveys in those (homeless youth, young drug injectors) who are less likely to be reached in a household survey. These young people often are at elevated risk compared to those living in household settings.

Surveys in young people should be repeated every two to three years, with sample sizes between 400 and 500 in each age and sex group (males and females younger than 20, and 20 to 24 years of age).