Scientists Reaffirm Therapies' Effectiveness in Preventing Mother-to-Child HIV Transmission

According to the findings of two new studies, mother-to-child transmission of HIV during breastfeeding could be virtually eliminated through the timely use of anti-retroviral drugs.

The studies, one conducted in Botswana and the other in Malawi, compared the effectiveness of anti-retroviral drug regimens given to HIV-infected mothers to prevent the spread of the AIDS virus to their uninfected newborns.

In the Botswana study, researchers wanted to see if one commonly-used drug cocktail was superior to another in preventing mother-to-infant HIV transmission in 560 infected women.

"And what we found is that when we started any of the regimens during pregnancy, during the third trimester of pregnancy, and continued them through six months of breast feeding, we had extremely low rates of mother-to-child transmission (of HIV)," said the author of the study, Roger Shapiro with Harvard University's School of Public Health in Boston.

Shapiro and colleagues found that with no drug protection, there's a 40 percent chance that an infected, breastfeeding mother will transmit the AIDS virus to her baby. With the drugs, the overall infection rate fell to 1.1 percent.

An international team led by Charles van der Horst of the University of North Carolina School of Medicine looked to see which treatment regimen gave newborns better protection - suppressing their mothers' HIV infections by giving the women the anti-retroviral drugs while pregnant or administering a drug syrup called nevirapine directly to the babies.

Based on a study of more than 2,300 breastfeeding women in Malawi, researchers say both strategies were very effective in shielding newborns from infection.

Research leader van der Horst says the study also found that treating newborns directly with the sweet syrup may turn out to be the better strategy. He also says only two percent of infants in the study became infected with HIV through their mothers' breast milk.

"People will see how easy it is to give the infants the daily dose of nevirapine. And since we decreased transmission to such low levels, I think instead of 200-thousand babies getting infected every year, it will be down to less than a hundred babies," he said.

In many poor countries, especially in Africa, HIV-positive women face a painfuldilemma in deciding whether to breastfeed, according to Lynne Mofenson of the US National Institute of Child Health and Human Development.

If they nurse, Mofenson says, they risk infecting their babies with HIV. Not breastfeeding exposes the newborns to illnesses from the often unclean tap water used to mix formula.

Regardless of which drug regimen is used, Mofenson says what's needed is a more aggressive strategy to reach, test and treat HIV-infected pregnant women. "Almost all of infant infections and maternal deaths occur in that group of women who have symptoms," he said.

Lynne Mofenson's comments on mother-to-child HIV transmission, and the results of the two African drug trials, are published this week in the New England Journal of Medicine.