Natural history of HIV infection

Abstract

The original description of AIDS, or the acquired immune deficiency syndrome, appeared in 1981. It described 26 patients with Kaposi’s sarcoma, a skin tumour which until then was seen only in elderly men, in African races, and in those with considerable iatrogenic immunosuppression, and in five men with oral thrush and Pneumocystis pneumonia which, again, was usually associated with iatrogenic immunosuppression. The connection between the two groups was that the men were all young male homosexuals with a mean age of 32 years 1, 2. The first nine cases of AIDS amongst injection drug users were diagnosed retrospectively to have occurred in 1980, and four of these were also homosexuals3. The first case of tranfusion-associated AIDS occurred in a young child who had a platelet transfusion4. Between 1978 and 1983 in the United States the risk of acquiring HIV via blood transfusion was estimated at 0.6 cases of AIDS per 100000 adults transfused, and 2.8 cases of AIDS per 100000 children transfused5. The risk was increased by a factor of 32 for adults given more than 10 units of blood and by a factor of 27 for children given more than 10 units of blood6. The risk with whole blood, packed cells, platelets or frozen plasma and the mean incubation period from transfusion to the development of AIDS was 21 months for children and 31 months for adults7. The risk of acquiring HIV from an infected blood product appeared to be about 66% and infection was more likely the closer the donor was to developing AIDS8. This does rather suggest that infectivity in donors rises as they develop symptoms. Other ‘high-risk groups’ were also soon recognized, including haemophiliacs, the heterosexual partners of patients with AIDS and children9, 10, 11, 12, 13, 14, 15, 16, 17, 18.