Retrovirus & Opportunistic Infections (cont.)
Several posters from this meeting discussed the topic of HIV superinfection, a situation where a chronically infected individual is infected with a second strain of HIV. Most data in this area has shown superinfection in relatively small numbers of people who were infected within the last year or two. Several other studies have not been able to demonstrate such events occurring in those chronically infected. Mary Campbell and colleagues looked very carefully at a group of men chronically infected that had unprotected exposures and was unable to see any detections of super-infection. This is an area of increasing interest and has major implications for patients as we discuss ways they can protect themselves from being superinfected, a situation which can be associated with disease progression.
While mother to child transmission in the developed world has become uncommon in the era of potent antiretroviral therapy, it remains an important issue in developing countries where such therapy is unavailable. In these countries there has been great success in reducing transmission with the use of single dose NVP therapy. However, the consequence of this is the frequent development of drug resistance. There is some concern that the benefits may not be present with single dose NVP during the second pregnancy in these women. One study reported data from 76 HIV-infected women who received single dose NVP to prevent mother-to-child transmission, and then again during a subsequent pregnancy. They found that there was no increased risk of transmission to their baby during the second pregnancy. There was a suggestion that if the second pregnancy occurred within 12 months of having previously received NVP there may have been an increased risk of transmission. It's hypothesized from this very small data set that perhaps after resistance is selected, overtime it becomes a minority species and does not impact on the efficacy of repeat NVP therapy for prevention of mother-child transmission. However, earlier re-exposure to NVP may select for pre-existing resistant variants and reduce the effectiveness of this therapy. Further study is needed in order to clearly understand what the implications are of single dose NVP to prevent mother to child transmission in the developing world and the implications for subsequent pregnancies.
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Last Editorial Review: 2/8/2006