|Studies Show Drugs Can Prevent HIV Transmission Through
February 7, 2008
A collection of studies presented at the Fifteenth Conference on Retroviruses and Opportunistic Infections in Boston have shown that the risk of HIV transmission from mother to child through breast milk can be reduced using antiretroviral treatment. The first set of studies looked at giving antiretroviral drugs to infants, and another focussed on treatment for HIV positive mothers.
One study based in Malawi gave the antiretroviral drug nevirapine to babies of HIV positive mothers for 14 weeks. The risk of HIV transmission to infants during breastfeeding was shown to be significantly lower at the end of 14 weeks. Furthermore, by 9 months of age only 7 percent of the infants taking the extended nevirapine regimen had become infected with HIV, compared with 13 percent of those that had received only single dose nevirapine, which is the current standard of care.
In similar trials in Ethiopia, India, and Uganda, babies were given nevirapine for 6 weeks, and were found to have a 50 percent lower risk of HIV infection after this time. Results were combined to evaluate outcomes in overall HIV transmission risk at six months, and infants were found to have a 20 percent lower risk of HIV infection than infants who received only one dose of nevirapine.
Nevirapine is already used widely in resource-limited settings for preventing HIV transmission from mother to child (PMTCT) during pregnancy, labour and delivery. Although breastfeeding poses a risk of HIV transmission to the infant, in some cases it is still recommended for HIV-positive women in resource poor countries, due to other risks associated with formula feeding. The findings could potentially influence World Health Organisation infant feeding guidelines.
The extended nevirapine regimen was found to be safe and effective on the whole, but there is concern about the potential for nevirapine resistance for those infants that did become infected with HIV.
The second set of results from the Kisumu Breastfeeding Study showed low rates of HIV infection among infants when mothers were given triple combination antiretroviral therapy from late pregnancy through to the sixth month of breastfeeding. In addition, babies received single dose nevirapine within 72 hours of birth. The women were advised to exclusively breastfeed and to wean their children rapidly at six months.
The researchers state that further assessment is still needed to determine whether this is a feasible strategy for PMTCT among breastfeeding HIV positive women. The study provided this regimen to HIV positive mothers who did not qualify for their own treatment according to WHO criteria.
Both sets of findings represent potential breakthroughs for PMTCT efforts in the developing world, and are likely to provoke debate about the best way of reducing the risk of HIV transmission through breastfeeding.
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