[HIV epidemiology]

Twenty-five years after the description of the first cases of AIDS, the HIV pandemic remains a major public health problem. Although often described as a single epidemic, there are many distinct epidemiological situations. Individual-level risks are at the center of this evolution and influenced by social, economic and political contexts. The overall situation in Europe and the Americas seems stable in recent years. However, the generalized epidemics in sub-Saharan Africa continue to spread and new hidden epidemic foci involving specific risk populations are emerging throughout the rest of the world. A multidimensional approach, tailored to the particular socio-cultural context, is essential to control these complex and diversified epidemics.