Three months of extra treatment with the drug nevirapine helps babies ward off the AIDS virus longer, and infected women do not need to rush to wean their infants, researchers reported on Wednesday.

Separate studies in two African nations address a pressing problem in developing countries, where 200,000 children each year pick up HIV through their mother’s breast milk.

Doctors are seeking the least expensive way to protect the babies from HIV while trying to not discourage breast-feeding, which prevents other diseases.

A study of thousands of newborns in Malawi found that adding 14 weeks of treatment with nevirapine to the standard therapy - one dose of nevirapine plus a week of treatment with AZT or zidovudine - halved the infection rate at 9 months to 5.2 percent.

Nevirapine is sold under the brand name Viramune by privately held Boehringer Ingelheim.

Giving nevirapine plus AZT for 14 weeks offered no additional benefit, and may have produced more side effects, they reported in the New England Journal of Medicine.

In the second study, designed to see if quickly weaning babies produced fewer infant AIDS cases, a team led by Dr. Louise Kuhn of Columbia University found little benefit.

They studied 481 Zambian babies whose mothers had been encouraged to abruptly wean them at 4 months. Just over 68 percent of the babies were uninfected at 2 years.

Among 477 Zambian women who were encouraged to breast-feed as long as they wanted, the virus-free survival rate was about the same - 64 percent.

WEANING AND DEATH

But among babies already infected by the age of 4 months, encouraging their mothers to stop breast-feeding dramatically increased their risk of death. Nearly 74 percent had died before their second birthday, compared to a 55 percent death rate among the babies whose mothers had been told to keep nursing.

Preliminary results from this study prompted the World Health Organization to change its breast-feeding recommendations for women in developing countries.

“The Zambia study showed that there was really no benefit to stopping breast-feeding early at 4 months. So breast-feeding is better than not breast-feeding,” said Lynne Mofenson of the National Institute of Child Health and Human Development, the project officer for both studies.

“But breast-feeding brings along with it the problem of HIV transmission, and what the Malawi study is showing for the first time is if you give the baby small amounts of anti-HIV drugs for the first 14 weeks of life, you can reduce the risk of HIV infection at 9 months by 50 percent or more,” she said in a telephone interview.

“Those two things say you should exclusively breast-feed the baby and you should give the baby antiretroviral drugs for at least 14 weeks.”

The institute is now looking at whether longer drug treatment will be even more beneficial.

“Right now it’s estimated that under 20 percent of HIV-infected women are receiving any prophylaxis to prevent mother-to-child transmission, so we’re having difficulty implementing even the single-dose nevirapine regimen. However, things are changing relatively rapidly,” Mofenson said. “Four years ago it was only 7 percent.”

By Gene Emery
BOSTON (Reuters)