Antiretroviral therapy given to babies after birth
offers protection against HIV infection, according to
researchers from the Johns Hopkins
Bloomberg School of Public
Health. 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. Their
study, "Short post-exposure prophylaxis in newborn babies
to reduce mother-to-child transmission of HIV-1; NVAZ
randomized clinical trial," is published in the Oct. 11
issue of The Lancet.
Lead author Taha El Tahir Taha, associate professor in
the 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.
"These factors limit the use of nevirapine before
delivery. Another approach to prevent transmission of the
disease is clearly necessary," he said. "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 six to eight
weeks.
At the six-to-eight-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 5 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 orally
to babies immediately after birth: a single dose of
nevirapine followed by zidovudine twice a day for seven
days. Giving postexposure prophylaxis only to the baby is
also easier than giving antiretrovirals to pregnant women
and their newborns, especially in areas where resources are
scarce.
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
School of Public Health, co-authored the study.
Research was supported by grants from the Fogarty
International Center, National Institutes of Health and the
Doris Duke Charitable Foundation.