Giving daily antiretroviral drugs (ART) to HIV-infected moms or their breastfeeding babies for 28 weeks proved safe and effective for preventing mother-to-child HIV transmission through breast milk, scientists observed.
It was an early results of a large-scale randomized study published in 2010 and led by researchers from the University of North Carolina at Chapel Hill.
Now, they have found that early weaning - stopping breastfeeding before six months - is of little, if any, protective value against HIV transmission nor is it safe for infant survival.
The latest findings came from the Breastfeeding, Antiretrovirals, and Nutrition (BAN) trial that was conducted in Lilongwe, Malawi, between April 21, 2004 and January 28, 2010.
The study involved more than 2,300 HIV-infected breastfeeding mothers and their newborn babies. BAN investigators were from the U.S. Centers for Disease Control and Prevention (CDC), UNC-Chapel Hill, and UNC Project-Malawi in Lilongwe, Malawi.
In 2010, BAN investigators reported early results demonstrating a 74 project reduction in HIV transmission to the breastfeeding babies if they were taking a single daily dose of the antiviral medication nevirapine for 28 weeks.
In light of this and other emerging evidence, the World Health Organization in 2010 recommended that antiretroviral drugs be given to either HIV-infected mothers or infants throughout breastfeeding.
In the latest and long-term (48 week) BAN trial, the researchers focused specifically on the safety and effects of weaning and stopping of maternal or infant ART at 28 weeks after birth.
The study's first author is Denise J. Jamieson, MD, MPH from the CDC. Senior author and principal investigator of BAN is Charles van der Horst, MD, a professor in the UNC School of Medicine, Division of infectious diseases.
Jamieson and her BAN colleagues found the overall risk of HIV transmission was significantly greater at 48 weeks (7 percent) in the control group of infants (breastfeeding only) than in the maternal ART group (4 percent) and the infant ART group (4 percent).
However, about a third of the infants became HIV infected after most mothers said they had stopped nursing their babies at 28 weeks after giving birth.
"Our 48-week follow-up of women in Malawi has shown that either infant or maternal prophylaxis [with ART] effectively reduces postnatal HIV transmission and that this protective effect persists until after breastfeeding cessation," stated Dr. Jamieson.
"However, transmission does occur after mothers report that they have weaned their infants," he added.
The report also noted that infant illnesses (diarrhea, malaria and TB), growth problems, and deaths significantly increased after early weaning.
"Breastfeeding is essential for babies in Malawi. There should be no early weaning and anti-HIV medications given to the mother or infant should be continued throughout the breastfeeding period," Dr. van der Horst suggested.
A report of the latest outcomes appears in the online edition of The Lancet.