July 10, 2008
Researchers at the Johns Hopkins Bloomberg School of Public Health have found that an extended AIDS drug regimen can cut by 50 percent an HIV-positive mother's risk of transmitting the virus to her infant during breastfeeding.
Of the 500,000 babies who contract HIV each year from their mothers, half are infected through breastfeeding. To counter this risk, nearly all HIV-positive mothers in Western nations feed their infants formula. But in the developing world, conditions like poverty and the lack of clean water often make formula-feeding impractical. And because of its many health benefits, breastfeeding has been shown to increase overall infant survival rates, even when the mother has HIV.
To prevent mother-to-baby transmission, most infants born to HIV-positive mothers in the developing world receive one dose of nevirapine shortly after birth. The new study, based in Malawi, expanded this regimen.
Researchers divided 3,016 breastfeeding infants into three groups. Babies in one group received a single dose of nevirapine; babies in the second group received nevirapine for 14 weeks; babies in the third group received nevirapine and zidovudine for 14 weeks. HIV infections through breastfeeding dropped by half in the second and third groups, and the infants showed no adverse effects from the longer treatment.
Dr. Taha E. Taha, a study co-author, said plans are under development to roll out the treatment in Malawi and elsewhere. Because international aid subsidizes the cost of nevirapine and zidovudine in much of sub-Saharan Africa, "The cost is not the major barrier," Taha said. "The logistical barriers will be key."
Dr. Brooks Jackson, an AIDS expert at the Bloomberg School of Public Health, agreed, noting that 30 percent of HIV-positive African mothers still do not receive nevirapine during labor, even though this intervention was proven nine years ago to halve viral transmission.
Further studies are planned to assess the effect of extending infants' antiretroviral treatment for six months or longer.
The study, "Extended Antiretroviral Prophylaxis to Reduce Breast-Milk HIV-1 Transmission," was published in the New England Journal of Medicine (2008;359(2):119-129).