Antiretroviral Therapy After Birth Decreases Mother-to-child HIV Transmission

They found that a regimen of nevirapine and zidovudine is 36 percent effective in blocking the transmission of HIV from mother to child. The researchers also report that giving these drugs to babies after birth is easier to administer when compared to giving antiretrovirals to mothers during pregnancy. <>p>"Short post-exposure prophylaxis in newborn babies to reduce mother-to-child transmission of HIV-1; NVAZ randomized clinical trial" is published in the October 11, 2003, issue of The Lancet.

Lead author Taha El Tahir Taha, MBBS, PhD, MPH, MCM, associate professor in the School's Department of Epidemiology, with a joint appointment in the Department of Population and Family Health Sciences, explained that nevirapine is typically given to mothers prior to delivery and to the baby after birth to prevent mother-to-child transmission of HIV. In Sub-Saharan Africa, most women arrive at medical facilities only a few hours before delivery and with an unknown HIV status, making it difficult to counsel them and test for HIV.

He said, "These factors limit the use of nevirapine before delivery. Another approach to prevent transmission of the disease is clearly necessary. In this study, we've shown that exposure after birth to prophylaxis with nevirapine and AZT can reduce mother-to-child transmission of HIV."

The researchers studied babies from 1,119 Malawian women with HIV-1 who presented late for delivery to determine if treatment with a combination of nevirapine and zidovudine as compared to a regimen of nevirapine alone reduced transmission of the disease. Infant HIV was tested at birth from cord blood samples and at 6-8 weeks. At the 6-8 week mark for babies who were HIV negative at birth, the protection rate was 7 percent for the 484 babies who received nevirapine and zidovudine and 12 percent for the 468 babies who received nevirapine only. The net reduction of overall mother-to-child transmission was five percent. These results are comparable to rates observed in studies in South Africa and Uganda, where antiretroviral drugs were given to both mother and infant.

The researchers also explain in their study that a regimen of nevirapine and zidovudine is easily given to babies orally immediately after birth a single dose of nevirapine followed by zidovudine twice a day for seven days. Giving post-exposure prophylaxis only to the baby is also easier than giving antiretrovirals to pregnant women and their newborns, especially in areas where resources are scare.

Dr. Taha said, "When it is not possible to give intrapartum nevirapine to the mother, it is still beneficial to give the intervention to the baby after birth. The baby will be afforded additional protection by receiving a second antiviral drug. With these new, promising results, we believe that alternative drugs may also be used as safety data become available. These regimens could also be extended to prevent transmission of HIV through breast milk."

Newton I. Kumwenda and Amanda Gibbons, both with the Johns Hopkins Bloomberg School of Public Health, co-authored the study. Additional co-authors were Robin L. Broadhead, Susan Fiscus, Valentino Lema, George Liomba, Chiwawa Nkhoma, Paolo G. Miotti and Donald R. Hoover.

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Research was supported by grants from the Fogarty International Center, National Institutes of Health and the Doris Duke Charitable Foundation, N.Y.