HIV infection remains of major public health importance in Europe, with evidence of continuing transmission of HIV in Europe. Overall, despite incomplete reporting, there is no clear indication of a decline in the number of cases being diagnosed each year. Since 2004, the rate of newly diagnosed cases of HIV reported per 100000 population has increased by almost 30%, from 6.6 per 100000 population in 2004 to 8.5 per 100000 in 2009. The number of diagnosed AIDS cases has continued to decline in the WHO European Region, except in the East, where the number of AIDS cases has increased. Among the 48 countries consistently reporting AIDS data for 2004–09, the rate of reported AIDS diagnoses declined from 2.0 per 100000 population to 1.0 per 100000.

In the three geographical/epidemiological areas, the predominant transmission mode varies by area, illustrating the wide diversity in the epidemiology of HIV in Europe. Although the reported data suggest that heterosexual transmission has become the dominant mode of transmission in the East, the inclusion of cases from Russia, not available for this report, would significantly increase the relative proportion contributed by injecting drug use. Injecting drug use would then account for more infections in the Region as a whole and in the East in particular. In the Centre the predominant mode of HIV transmission is sex between men followed by heterosexual contact. Similarly, in the West, the predominant transmission mode is sex between men, followed by heterosexual contact, when cases originating from countries with generalised epidemics are excluded.