Transmission and Prevention of Hiv: Missing Links in the Aids Pandemic*

Recent studies that have characterized the biology of HIV infection have suggested potential limitations of current approaches to HIV prevention, in addition to new strategies to interrupt transmission of the virus. The transmission of HIV is influenced by several factors related to the virus (eg, viral clade or viral load) and the host (eg, heritable mutations that confer resistance to HIV infection). The production of HIV is intermittently amplified in the genital tract, resulting in periods of increased infectivity. Accordingly, the likelihood of HIV transmission also is affected by coinfection with other sexually transmitted diseases and by the stage of illness, with the highest risk of transmission occurring during the earliest and latest phases of infection. The period of acute HIV infection is an especially important time of high viral production and low awareness of infection. RNA testing may help to identify individuals with early HIV infection who are not typically identified by conventional antibody screening. Antiretroviral therapy has been shown to reduce the amount of HIV in semen. In retrospective studies, antiretroviral agents have been associated with reduced likelihood of HIV transmission. Prospective studies to examine the effects of pharmacologic therapy on HIV transmission are in progress. (Adv Stud Med. 2006;6(3B):S157-S162)