2nd-generation HIV surveillance and injecting drug use: uncovering the epidemiological ice-berg

Summary Objectives: HIV/AIDS surveillance methods are under revision as the diversity of HIV epidemics is becoming more apparent. The so called “2^nd generation surveillance (SGS) systems” aim to enhance surveillance by broadening the range of indicators to prevalence, behaviors and correlates, for a better understanding and a more complete and timely awareness of evolving epidemics. Methods: Concepts of HIV SGS are reviewed with a special focus on injecting drug users, a major at-risk and hard to reach group in Europe, a region with mainly low or concentrated epidemics. Results: The scope of HIV/AIDS surveillance needs to be broadened following principles of SGS. Specifically for IDUs we propose including hepatitis C data as indicator for injecting risk in routine systems like those monitoring sexually transmitted infections and information on knowledge and attitudes as potential major determinants of risk behavior. Conclusions: The suggested approach should lead to more complete and timely information for public health interventions, however there is a clear need for comparative validation studies to assess the validity, reliability and cost-effectiveness of traditional and enhanced HIV/AIDS surveillance systems. Submitted: 24 October 2005; Revised: 19 June 2006; Accepted: 5 October 2006