The impact of HIV epidemic phases on the effectiveness of core group interventions: insights from mathematical models
- 1Centers for Disease Control and Prevention, National Center for HIV, STD, and TB Prevention, Atlanta, Georgia, USA
- 2Groupe de recherche en épidémiologie de l'Université Laval, Hôpital du Saint-Sacrement du CHA, Quebec, Canada
- Correspondence to: Dr Marie-Claude Boily, Centers for Disease Control and Prevention, National Center for HIV, STD, and TB Prevention, Division of Sexually Transmitted Diseases Prevention, Statistics and Data Management Branch, Mailstop E63, 1600 Clifton Road, Atlanta, GA 30333, USA;
- Accepted 30 November 2001
Mathematical models have highlighted the disproportionate contribution of core group transmitters to the spread of sexually transmitted diseases. Because the effectiveness of interventions varies with time, it has been suggested that epidemic phases should be considered in the design of prevention strategies. This study aimed to examine the impact of HIV epidemic phases on the effectiveness of HIV interventions based on gonorrhoea screening and condom use, targeted to core groups. The results are based on a mathematical model of gonorrhoea and HIV transmission in a relatively slow spreading HIV epidemic using Cotonou (Benin) as an example. For epidemics with a low reproductive potential modest core group interventions can significantly reduce HIV incidence and prevalence. As the epidemic matures, effective interventions should also incorporate core and non-core populations. For epidemics with a high reproductive potential, core group interventions are necessary but not sufficient to have a rapid and large scale impact. A more general population approach is also needed early in the epidemic. Epidemic phases are also important in the evaluation of prevention strategies.