Treatment scale-up: public health arguments
Two considerations stand out among the public health arguments for emergency treatment scale-up. First is the sharp reduction in HIV/AIDS-related morbidity and mortality associated with treatment. This has been documented in high-income countries, in Brazil's national treatment programme (see Box 2.1) and in pioneering projects in resource-poor settings (1-3). Second is the synergistic effect that treatment can have on prevention efforts. The availability of treatment can enhance prevention in several ways:
- Increased demand for voluntary counselling and testing: providing opportunities for voluntary counselling and testing is crucial to effective prevention. As many as 9 out of 10 HIV-infected people in sub-Saharan Africa do not know their serostatus; and when treatment is unavailable, people may see little reason to find out. But the availability of treatment has been shown in numerous settings to increase voluntary counselling and testing - for example, it rose by 300% at a clinic in Haiti after antiretroviral therapy was introduced (4).
- Enhanced opportunities for secondary prevention: coming to health centres for treatment offers patients the chance to receive information about prevention behaviours. The value of this approach is reflected in HIV-prevention strategies recently designed by the United States Centers for Disease Control and Prevention to target people known to be infected (5).
- Lower risk of transmission: treatment lowers the likelihood of sexual transmission of HIV in the case of unprotected sexual intercourse. It must be recognized, however, that the longer life expectancy of patients on treatment will probably lead to an increase in sexual relations between people of different serostatus.
There is little evidence from developing countries of how treatment availability affects risk behaviours. Planning and careful measurement are needed to make treatment and prevention efforts work effectively together. As treatment is scaled up, programmes will continuously have to measure the impact on prevention and be able to adapt and respond promptly to any weakening of preventive behaviours.