There are many examples of an apparent resistance to HIV/AIDS, and they have been known for some years now. There are at least several hundred recorded cases of sex workers in central and southern Africa, arguably at the highest risk of infection anywhere in the world (as incidence of the virus are extremely high and condom use very unpopular) who are unaccountably not infected. This can only be explained by some kind of natural immunity. The problem with conducting organised research into this phenomenon is that the people in question are very reluctant to come forward, because of the stigma associated both with their profession and the disease itself. Lack of financial resources doesn't help, either.

Another piece of evidence that the HIV virus is not one size fits all is the distribution of HIV/AIDS infection across the continent of Africa. Central and southern Africa are notorious for being the areas with the highest incidence of the disease in the world - as high as %30 in some countries. Unaccountably, North Africa is one of the places with the lowest incidence, and the Middle East has the lowest infection rate of anywhere in the world, including the industrialised countries where condom use and sex education are of a much higher level.

Initially this striking difference in such relative physical proximity tended to be attributed to differences in social mores and behaviour induced by religion. However, it emerges that Black Africans are not so promiscuous, and Middle Eastern Muslims not so chaste, as was previously believed. Even in countries where the two populations come into contact, such as Sudan, Libya and Egypt, the demarcation line seems at least to run among racial grooves. Unfortunately, the aforementioned social taboos make research of individuals in these countries very difficult, as well as the fact that many of them live under totalitarian regimes which do not allow much interaction with Western scientists for their citizens.

This evidence, impressive as it is, is somewhat complicated by the fact that different parts of the world are afflicted with different strains of the virus. The disease is not exactly the same for someone who is infected in Europe as, say, Botswana. Southern Africa emerges to have been struck by the double whammy of the lowest natural immunity levels and the most virulent strain of the virus. Nevertheless, the evidence to suggest natural immunity is mounting and research is being done, however slowly.