Breast-feeding exclusively lowers risk of vertical HIV transmission to children in developing countries

HIV-positive women in developing countries could reduce the risk of transmitting the virus to their infants if they exclusively breast-feed rather than supplement breast milk with formula, animal milk or solid food, according to a study published in the March 31 edition of the Lancet, Reuters reports (Dunham, Reuters South Africa, 3/30).

The study, led by Hoosen Coovadia and Nigel Rollins of the Africa Centre for Health and Population Studies at the University of KwaZulu-Natal, enrolled 2,722 HIV-positive and HIV-negative women and 1,372 infants. The researchers compared the risks of vertical HIV transmission and survival rates for infants exclusively breast-fed with infants who received formula, animal milk or solid food in addition to breast milk (Coovadia et al., Lancet, 3/31). According to BBC News, 4% of the exclusively breast-fed infants had a risk of becoming HIV-positive between ages six weeks and six months (BBC News, 3/30). The study found that infants who received milk and solid food were 11 times more likely to become HIV-positive than infants who were exclusively breast-fed, London's Guardian reports. In addition, infants who received both formula and breast milk were twice as likely to become HIV-positive as exclusively breast-fed infants (Boseley, Guardian, 3/30). According to researchers, the higher risk of vertical transmission among infants who received solid food might be because proteins in the food facilitate entry of the virus into the gut wall (Reuters, 3/30). About 6.1% of the exclusively breast-fed infants died by age three months, compared with 15.1% of the infants who received other food sources (AFP/Yahoo! News, 3/29). According to the researchers, breast milk might reinforce and protect the mucus membrane lining of the intestines, serving as a barrier to HIV, Reuters reports. Rollins said that if women in developing countries exclusively breast-feed, about 50,000 to 100,000 infant deaths would be prevented annually. Rollins added, "For the health and well-being of her child, exclusive breast-feeding is more than likely going to protect the child both from transmission and the other risks to her child's survival" (Reuters, 3/30). In an accompanying comment piece, Wendy Holmes of the Centre for International Health and Felicity Savage of the Centre for International Health and Development write that the study's findings are a "breakthrough" that provide "crucial confirmatory evidence that" when HIV-positive women exclusively breast-feed, their infants have "only a low risk of infection with HIV." They add that the study's findings "emphasize that promotion of exclusive breast-feeding for all mothers and babies could prevent much pediatric HIV infection, as well as deaths from other causes" (BBC News, 3/30).

Physicians Call for Change to Breast-Feeding Guidelines
Some physicians on Friday in response to the study called on the United Nations to change its guidelines on breast-feeding for HIV-positive women in developing countries, the Guardian reports (Guardian, 3/30). The World Health Organization in October 2006 released a statement that recommends HIV-positive women breast-feed exclusively until an infant is six months old unless alternatives are "acceptable, feasible, affordable and safe for both the mother and infant." Several governments in developing nations have followed these guidelines, and some have encouraged HIV-positive women to stop breast-feeding earlier than six months in an effort to reduce the risk of vertical transmission. According to the United Nations, about 300,000 infants die annually after becoming HIV-positive through breast-feeding. UNICEF estimates that 1.5 million formula-fed infants die annually from other diseases. A series of studies presented last month at the 14th Annual Conference on Retroviruses and Opportunistic Infections in Los Angeles suggest the benefits of breast-feeding in developing countries might outweigh the risk of vertical HIV transmission. Three studies conducted in Africa found that HIV-negative infants who were breast-fed by HIV-positive mothers from birth up to age six months had increased rates of severe diarrhea that resulted in hospitalization or death compared with infants who were breast-fed for longer than six months. Another study found high rates of diarrhea and malnutrition among formula-fed infants in Botswana after a 2006 flood led to water contamination. Following the sewage contamination of the water and the environment, deaths from diarrhea in Botswana were 25 times higher in 2006 than in previous years. A fifth study conducted in Zambia found an increased death rate among infants of HIV-positive women who were breast-fed until age four months (Kaiser Daily HIV/AIDS Report, 2/27).

The study is available online.