June 9, 2008

Preventing HIV Transmission from Mother to Infant in Poor Regions

Photo of a mother of African descent with her infant

In many poor countries, mothers with HIV face a stark choice: to nurse their infants and risk passing on HIV through their breast milk, or formula feed and deprive their infants of the natural benefits of breast milk. Two new studies shed light on HIV transmission between breastfeeding mothers and their infants in resource-poor areas.

Breast milk contains protective antibodies that help infants ward off disease. However, in the developed world, mothers with HIV often forego breastfeeding and instead feed their infants formula to avoid passing on the virus. But in many poor countries, clean water to mix formula isn’t always available. Some families may have difficulty affording infant formula or the fuel needed to boil water for preparing it. The new studies, published online in the New England Journal of Medicine on June 4, 2008, provide some insight for breastfeeding in these situations.

One of the studies—supported by NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and others—was conducted in Lusaka, Zambia, by researchers at Columbia University, the Boston University School of Public Health, the University of Zambia and other institutions. The team enrolled 958 women with HIV and their infants and randomly assigned them to 2 groups. In the first, the women were counseled to exclusively breastfeed their infants for 4 months, then stop all breastfeeding and switch to formula. The women were provided with formula and instructed in how to safely prepare it. Women in the second group were advised to continue breastfeeding for as long as they chose.

The researchers were surprised to find no significant difference in HIV infection rates between the 2 groups. In fact, for infants infected with HIV, death rates rose when breastfeeding ended abruptly.  The deaths were primarily due to diarrheal and respiratory diseases, but also included other causes.

“In poor countries where sanitation is a problem, exclusive breastfeeding appears to confer the greatest benefits to infant health and survival, even in mothers with HIV,” said Dr. Duane Alexander, director of NICHD.

“Formula feeding is a hardship in many poor countries,” said Dr. Lynne Mofenson, NICHD’s project officer for the 2 studies. “So the finding that it doesn’t confer any apparent benefits in resource-poor settings—and may even be harmful—has important implications.”

The other study, conducted in Malawi and co-sponsored by NICHD and the U.S. Centers for Disease Control and Prevention, provides insight into how to prevent HIV transmission by infected women who are breastfeeding. A team led by scientists at Johns Hopkins University and the University of Malawi College of Medicine studied 3,016 infants who did not have HIV at birth. The researchers compared the country’s standard treatment—a single dose of nevirapine given to the mother during labor and to the infant at birth, with daily doses of zidovudine given to the infant during the first week of life—to 2 more extended regimens.

The team found that both of the extended anti-HIV regimens greatly reduced the risk of HIV infection in breastfeeding infants compared to the standard treatment. The authors note that additional studies will be needed to determine an ideal regimen.

NIH continues to sponsor studies to determine the most effective ways to prevent the spread of HIV through breast milk.

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