July 10, 2001
John Sullivan from the University of Massachussetts gave an overview of the progress being made in preventing mother-to-child transmission of HIV. This is the area in which we have perhaps made the greatest strides in preventing HIV transmission.
Sullivan reviewed the science of HIV transmission, reminding us that transmission occurs in utero, during the delivery process, and by breast feeding. Roughly one third of HIV infections in non-breast-fed children occur in utero; two thirds are infected during delivery. Breast feeding will lead to infection in an additional 10-14% of children. HIV transmission most often occurs during the first six months of breast feeding, although the risk remains as long as the child is breast fed. Prevention of HIV transmission through breast feeding is one of the great challenges in resource-poor settings. Recent evidence, reviewed by Dr. Sullivan, suggested that some of the children infected in utero are infected as early as the second trimester.
Since the release of PACTG 076 in 1994, we have made enormous strides in preventing transmission. Reviewing data from developed countries, Dr. Sullivan demonstrated the increasing use of highly active therapy in pregnant HIV-infected women. He pointed out that transmission is very low when the maternal viral load is low, but there is an additional protective effect of antiretroviral therapy. Three-drug therapy is associated with HIV transmission rates that approach zero.
In the developing world, however, many obstacles still remain. A series of trials have demonstrated that short courses of zidovudine, or zidovudine and lamivudine can prevent up to half of all infections. The HIVNET 012 study demonstrated that a single dose of nevirapine for the mother, followed by one dose in the infant, reduces transmission to one half of that found with a short course of zidovudine. This was confirmed by the SAINT trial in South Africa, which showed that single-dose nevirapine was as effective as zidovudine and lamivudine during delivery followed by one week of therapy for the infant.
Dr. Sullivan outlined the challenges that remain. These include delivering testing and treatment to all pregnant women, understanding the optimal role of elective caesarian section, defining long term safety, and perhaps most challenging, dealing with breast-feeding HIV transmission in areas where no safe alternatives exist.
Dr. Sullivan proposed a bold solution. He argued that pregnant women with HIV throughout the world should be the first to receive HAART, and it should be continued after the baby is born. This would deal with the problem of breast-feeding transmission, and keep the mother alive as well. Leaving a world full of orphans if we cannot help their mothers would be a hollow victory.
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