Longer treatment with antiretroviral Nevirapine reduces risk of HIV among infants

Extended treatment with the antiretroviral drug nevirapine in conjunction with the standard therapy might reduce the risk of mother-to-child HIV transmission, according to a study published Wednesday in the New England Journal of Medicine, Reuters reports (Emery, Reuters, 6/4).

For the study, Taha Taha, co-director of the infectious disease program at Johns Hopkins' Bloomberg School of Public Health, and colleagues tested three drug regimens designed to prevent HIV transmission through breastmilk among 3,016 infants in Malawi. One regimen included the traditional treatment of a single dose of nevirapine plus one week of treatment with the antiretroviral zidovudine. The other regimens added daily doses of nevirapine or nevirapine plus zidovudine for 14 weeks after birth. The study found that infants who were administered the traditional regimen had the highest rate of HIV from ages six weeks to 18 months. At nine months, 10.6% of the infants in the traditional treatment group were HIV-positive, compared with 5.2% and 6.4% among the nevirapine-only and nevirapine-plus-zidovudine groups, respectively, according to the study (Taha et al., NEJM, 6/4).

In a related NEJM study, researchers examined whether weaning infants sooner reduced the risk of HIV, Reuters reports. The researchers examined 481 infants in Zambia whose mothers were encouraged to abruptly wean them at four months and 477 infants whose mothers were encouraged to breastfeed as long as they wanted. The study found that about 68% of infants in the first group were HIV-negative at two years after birth, compared with 64% among the infants breastfed for longer. Although the difference was not significantly different, the study found that among infants who were HIV-positive by age four months, the risk of death was increased among those whose mothers were encouraged to stop breastfeeding. According to the study, about 74% of HIV-positive infants whose mothers had been told to stop breastfeeding died of AIDS-related illnesses, compared to 55% of HIV-positive infants whose mothers were not told to stop breastfeeding. According to Reuters, preliminary results from the Zambia study prompted the World Health Organization to change its breast-feeding recommendations for women in developing countries.

Lynn Mofenson, project officer for both studies, said the "Zambia study showed that there was really no benefit to stopping breastfeeding early at four months. So breastfeeding is better than not breastfeeding." She added, "But breastfeeding 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 [infant] small amounts of [antiretroviral] drugs for the first 14 weeks of life, you can reduce the risk of HIV infection at nine months by 50% or more." She noted, "Those two things say you should exclusively breastfeed the [infant] and you should give the [infant] antiretroviral drugs for at least 14 weeks" (Reuters, 6/4).

The Malawi study is available online. The Zambia study also available online. An editorial related to both studies also is available online.