Several European countries are considering implementing surveillance systems for HIV infection, but questions remain regarding patient confidentiality. The population-based HIV/AIDS surveillance system in Norway integrates anonymous HIV case reports from laboratories and clinicians and named AIDS case reports. This evaluation includes a description of the system, evidence of system attributes, estimation of resources for system operations, and documentation of the system's usefulness. HIV case reports provide a far better picture of the epidemic than AIDS reports. The median delay between positive HIV test and reporting was 30 days (interquartile range 18-49 days). Completeness of demographic and epidemiologic information in the surveillance database ranges from 60 to 100%. Information on pre-AIDS mortality and emigration is incomplete. The system cost euro 25,200 in 1999. Results are published every week and used for planning of health care and prevention. We conclude that the Norwegian surveillance system with anonymous reporting of HIV cases is simple, inexpensive and flexible, and capable of providing a representative and timely overview that guides prevention. The system fulfils its objectives while respecting confidentiality and adhering to ethical principles. A similar system may be considered in other countries.
