Infant nevirapine more effective in preventing HIV transmission than maternal antiretroviral therapy

The largest study to date to examine methods to prevent HIV infection among breastfeeding infants concludes that giving antiretroviral drugs to HIV-infected breastfeeding mothers in sub-Saharan Africa or giving an HIV-fighting syrup to their babies are both effective.

"Our study found that both methods are effective in preventing HIV transmission, but given a choice between the two, I'd say that the baby regimen is the more successful method," said Charles Chasela, PhD, coordinator and lead author of the study, which was published in the June 17, 2010 issue of the New England Journal of Medicine.

"The antiretroviral regimen for treating the mothers is much more expensive and requires access to medical facilities that aren't widely available in developing countries such as Malawi, where our study was conducted," added Charles van der Horst, MD, a professor of infectious diseases in the UNC School of Medicine and senior author of the study. "The baby regimen, in comparison, is incredibly cheap and much easier to implement."

These findings are important, van der Horst said, because each year about 200,000 infants worldwide become infected with HIV through breastfeeding, and in the developing world infant formula is both prohibitively expensive and associated with increased infant deaths.

In the study, called the Breastfeeding, Antiretrovirals and Nutrition Study (BAN), 2,369 breastfeeding mother-infant pairs in Lilongwe, Malawi, were randomly assigned to one of three groups: a maternal antiretroviral therapy (ART) group, a second group in which infants were treated with nevirapine liquid and a control group for whom medications were given at the time of delivery only. None of these women had developed AIDS yet and thus did not need treatment for their own health.

After their babies were born, women in the maternal antiretroviral group received a single tablet twice a day containing the drugs zidovudine and lamivudine. They also received a dose of nevirapine by mouth once a day for 14 days and then twice daily from 2 to 28 weeks.

In the infant prophylaxis group, each infant received a dose of liquid nevirapine by mouth that increased with age, ranging from 1 milliliter a day in the first two weeks to 3 milliliters a day for weeks 19 through 28. Study personnel measured these doses into syringes which were given to the mothers, who then squirted the contents into their infants' mouths.

Mothers in the study were asked to wean their babies from breastfeeding by 28 weeks after birth and the study results were calculated after each participant in the treatment arms had completed 28 weeks of treatment. The results showed that infant nevirapine was 74 percent effective in preventing HIV transmission while maternal antiretroviral therapy was 53 percent effective. In addition, the study found that infants had significantly increased HIV-free survival no matter which intervention was used.

Based in part on these results, the World Health Organization (WHO) has recommended that HIV prevention guidelines for breastfeeding HIV-infected mothers, who were still in the early stages of HIV infection, be modified to offer them the choice of either dosing their uninfected infant with nevirapine syrup during breastfeeding or taking a triple drug regimen themselves.

The study was conducted as part of UNC Project-Malawi, a program of the UNC Institute for Global Health & Infectious Diseases that was established in 1996, and was funded by the U.S. Centers for Disease Control and Prevention.