The AIDS epidemic has unfolded very differently in different parts of the world, and among different populations. It is not always clear why HIV infection takes off in some places while rates in neighbouring countries remain stable over many years. However, there are several factors which clearly influence the shape of the epidemic. People on the move–escaping from abuse, or even just leaving their families in search of work–are especially likely to be exposed to infection. People whose daily existence is stressful and dangerous may not care about the long-term risks posed by HIV. People in conflict and refugee situations may have little control over their exposure to HIV, indeed even to sex. And the stigma that still attaches to HIV hinders people from protecting themselves and others from infection, or from seeking out care and support.
The different faces of AIDS can be seen in the following country situations, which illustrate some of the factors driving the epidemic.