More than 60 million people have been infected with HIV since the epidemic began two decades ago. In 2001, it claimed an estimated 3 million lives. 21.8 million people around the world have died of AIDS, 4.3 million of them children, by the end of 2001. Nearly twice that many - 42 million - are now living with HIV and most of these cases are likely to die over the next decade or so. The most recent UNAIDS/WHO estimates show that, in 2002 alone, 5 million people were newly infected with HIV. In the 45 most affected countries, it is projected that, between 2000 and 2020, 68 million people will die prematurely as a result of AIDS.

In many countries, AIDS is erasing decades of progress in life expectancy. The average life expectancy in sub-Saharan Africa is currently 47 years. Without AIDS, it would have been 62 years. In some countries, such as Botswana, up to one-third of the adult population is infected with AIDS. HIV/AIDS marks a severe development crisis in sub-Saharan Africa, the worst-affected region in the world. The scale of the epidemic means that the human and socioeconomic toll will remain massive for many generations. AIDS has orphaned at least 10.4 million children. AIDS also undermines countries' efforts to reduce poverty and improve living standards.

Unless action against the epidemic is scaled up drastically, the damage already done will seem minor compared with what lies ahead. This may sound dramatic, but it is hard to play down the effects of a disease that stands to kill more than half of the young adults in the countries where it has its firmest hold.