The most prominent and comprehensive source of data on the status of the HIV/AIDS epidemic worldwide is the Joint United Nations Programme on HIV/AIDS, often known as UNAIDS for short. Its website is at www.unaids.org.

This international organisation publishes a ‘Report on the global HIV/AIDS epidemic’ every two years; at the time of writing the last edition was published in 2002.

As well as providing an overall global picture, this report contains detailed country by country data, and the UNAIDS epidemiologists and statisticians go to great lengths to ensure that data from different countries are measured as far as possible in comparable ways. (Country by country reports are also available as a joint project of UNAIDS and the World Health Organization (WHO).

UNAIDS also publish regular updates on the state of the global epidemic. The most recent update was published in May 2006. It is not a pleasant read. It estimates that:

40 million people worldwide are living with HIV/AIDS

About 27 million of these people live in Africa south of the Sahara

In certain southern African countries (Botswana, Swaziland), nearly 40% of the population have an HIV infection

5 million people were newly infected with HIV during the single year 2003

3 million people (including 500,000 children under 15) died of AIDS in 2003

This article was published in August 2006; the latest statistics from UNAIDS published on 20th November 2007 revised estimates down to 33 million people living with HIV AIDS worldwide; 22.5 million of them in Sub Saharan Africa.