In the worst-case scenario of a recent report by UNAIDS on the evolution of the AIDS epidemic in Africa by 2025, up to 83 million Africans could die of AIDS-related illnesses in the next twenty years, unless concrete action is taken today to scale up the response to the disease, writes Mark Stirling, director of the UNAIDS Regional Support Team for Eastern and Southern Africa. What is essential, the author writes in this article, is investment in both HIV prevention and treatment. We cannot sacrifice one at the expense of the other. As impressive as the recent gains in the fight against AIDS may sound, the bottom line remains that today only 8 percent of Africans who need treatment are getting it. If the commitment displayed by African governments and the international community in scaling-up treatment during the last six months of 2004 is any indication, in all likelihood the worst-case scenario is the least likely scenario. But this will only be so if we remember that the commitments to scaling up prevention and treatment today are the beginning of a life-long commitment to improving the health and well-being of all Africans, especially those vulnerable to, living with and affected by HIV and AIDS.