The HIV/AIDS Surveillance in Europe mid-year report 2002 published by the European centre for the epidemiological monitoring of AIDS (EuroHIV, http://www.eurohiv.org) clearly illustrates that the HIV/AIDS epidemic affecting the World Health Organization European region consists of a multitude of diverse epidemics differing in time, place, person, and severity (1).

Increases of newly diagnosed HIV infections were observed in several countries of western Europe, including Belgium, Ireland, Norway, and the United Kingdom. Decreases were observed in others (Germany, Greece, and Switzerland) but might partly reflect changes in HIV surveillance systems. Overall numbers of new HIV diagnoses decreased among men who have sex with men (MSM) (-14% between 1997 and 2001) and injecting drug users (-15%), but increased among heterosexuals (+64%), of whom the majority originated from a country with an existing generalised HIV epidemic. The widespread use of highly active antiretroviral treatment (HAART) has produced a marked decline in AIDS incidence and deaths in western Europe. The number of AIDS cases diagnosed in 2001 (9065) was a third of that in 1995 (24 936) and the number of AIDS deaths (3082) less than one fifth (18 157). Data from the first half of 2002, however, suggest that the recent decline in AIDS incidence may be levelling off.

The situation in central Europe, where numbers of AIDS cases (<6 per million population) and newly diagnosed HIV infections (7-10 per million population) remain low and relatively unchanged, offers some cause for optimism (2). A strong Polish national response and well designed national HIV/AIDS programmes in countries of the former Yugoslavia have ensured that the epidemics associated with injecting drug use of the late 1980s have not become established within the wider population (2).

Eastern Europe is experiencing the fastest growing HIV/AIDS epidemic in the world (3) and almost 100 000 HIV cases (349 per million population) were diagnosed in 2001. Of cases for which probable route of infection was known, 89% were diagnosed among injecting drug users. Infection through heterosexual contact increased by 53% between 2000 and 2001, though absolute numbers remain low. Numbers of infections among MSM remain extremely low. HIV now affects all countries in eastern Europe. Estonia, Latvia, the Russian Federation, and the Ukraine all had rates of HIV diagnosis exceeding 100 per million population in 2001. Reported AIDS cases are generally low, partially reflecting the late arrival of HIV to this region, but also underdiagnosis and under-reporting in some countries.

While the rapid spread of HIV/AIDS is cause for great concern in eastern Europe, there is cause for some optimism in central Europe where the epidemic seems to be contained within high risk groups. The HIV/AIDS situation in western Europe, however, coupled with recent increases in high risk behaviours and higher rates of sexually transmitted infections (3), demonstrates that without effective and sustained prevention measures, HIV will remain a continual threat. As increased population mobility serves to increase the diversity of Europe's populations, prevention activities need to become more culturally appropriate and socially relevant in order to reach and benefit those who need them most.