An antiretroviral drug already in widespread use in the developing world to prevent the transmission of HIV from infected mothers to their newborns during childbirth has also been found to substantially cut the risk of subsequent HIV transmission during breast-feeding.
In a study presented Feb. 4 at the 2008 Conference on Retroviruses and Opportunistic Infections in Boston, an international team of AIDS experts reports that nevirapine given once daily to breast-feeding infants from 8 to 42 days old decreased by almost half the rate of HIV transmission via breast-feeding at 6 weeks of age. The decrease occurred in comparison to a single dose of nevirapine given to infants at birth, the current standard of care.
At 6 months of age, the risk of postnatal HIV infection or death in infants who received the six-week regimen was almost one-third less than the risk for infants given only a single dose. The study was led by three teams of investigators at The Johns Hopkins University in collaboration with investigators in Ethiopia, India and Uganda.
Breast-feeding remains a leading route of HIV transmission in the developing world. The United Nations World Health Organization estimates that approximately 150,000 infants are infected through breast-feeding each year. In the United States each year, fewer than 150 newborns are infected with HIV at birth, mostly to mothers who did not know they were HIV positive.
The study, conducted from 2001 to 2007 and involving approximately 2,000 infants, is one of the first randomized controlled trials to show that a drug can prevent HIV transmission to uninfected babies exposed to their infected mothers' breast milk.
According to Johns Hopkins scientists, the results are highly significant because the low-dose regimen of nevirapine was able to reduce transmission or death in breast-feeding infants. They note that the extended-nevirapine regimen appears to be as safe as the single-dose regimen.
The study is also significant, the scientists say, because it is the first to show that an antiretroviral drug can prevent HIV transmission through mucosal tissue.
This finding has implications for the potential value of antiretroviral drugs for preventing sexual transmission of HIV.
The six-week extended nevirapine trial, or SWEN study, included more than 200 scientists and staff collaborating in many countries. The project was directed by Johns Hopkins investigators J. Brooks Jackson, M.D., M.B.A., and Laura Guay, M.D., with colleagues at the Makerere University/Johns Hopkins University Research Collaboration in Kampala, Uganda; by Andrea Ruff, M.D., with colleagues at Addis Ababa University in Addis Ababa, Ethiopia; by Robert Bollinger, M.D., M.P.H., with colleagues at BJ Medical College in Pune, India.; and Lawrence Moulton, Ph.D., of Johns Hopkins, principal statistician for the study.
The SWEN study was funded by the Division of AIDS at the National Institute of Allergy and Infectious Diseases, one of the National Institutes of Health. Nevirapine is manufactured by the German pharmaceutical company Boehringer Ingelheim and sold under the brand name Viramune.
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