LOS ANGELES, CALIFORNIA--A tragic outcome of an HIV intervention meant to prevent transmission from infected mothers to their children is triggering yet another examination of breast-feeding recommendations. As part of public policy, Botswana advises that all HIV-infected women use infant formula to avoid transmitting the virus to their babies through breast milk. But a study of a deadly outbreak of diarrheal disease in children under 5 in that southern African country has found that infant formula, as compared to breast-feeding, increased a child's risk of death by 50 times, likely because of contaminated water used to make the formula.
In 2005, a third of the pregnant women in Botswana were infected with HIV, making it one of the hardest-hit countries in the world. Previous studies have shown that breast-feeding, depending on how long it's done, accounts for 5% to 20% of the transmissions from infected mother to their children. To help curb such transmission rates, the Botswanan government advised in 1998 that all HIV-infected women use infant formula as part of a comprehensive strategy that also included the use of anti-HIV drugs during labor and delivery. The formula recommendation goes a step beyond World Health Organization (WHO) advice, which cautions that HIV-infected women should use formula only when it is acceptable, feasible, affordable, sustainable, and safe.
In response to the government policy, 63% of infected mothers in Botswana now use formula, which is provided free by the government to protect their babies from the virus. But from January to March 2006, 532 children in the country under 5 died from diarrhea, up from 21 the year before.
To probe the reasons behind the outbreak, medical epidemiologist Tracy Creek of the U.S. Centers for Disease Control and Prevention in Atlanta, Georgia, and colleagues examined a cohort of 153 Botswanan children, 65% of whom had an HIV-infected mother. In this entire group, 22% of the children died; only one of them had been breast-fed. The HIV-infected status of the mother and the infant was not associated with any of the deaths. In one village, 30% of the formula-fed children died, whereas no deaths occurred in breast-fed babies, Creek reported here yesterday at the 14th Conference on Retroviruses and Opportunistic Infections. Stool samples taken from children in the study found that several dangerous pathogens had infected the children: 60% had Cryptosporidium, 50% had Escherichia coli, and 38% had salmonella.
Creek suspects that the severe flooding in Botswana in 2005 contributed to the outbreak by increasing the levels of microorganisms in the water supply. Because Botswanan mothers use this water to make infant formula, the "safety [of infant formula] may vary dramatically with the weather," Creek warned. Breast-feeding clearly carries a risk of transmission, but Creek stressed that it had to be balanced against the risks of formula in such settings. "A recommendation to all HIV-infected women to formula-feed is not based on the WHO guidelines," said Creek, whose team has advised Botswana to reevaluate its universal policy.
"It's an absolutely stunning story," says pediatrician Hoosen Coovadia of the University of KwaZulu-Natal in South Africa. "Avoidance or early cessation of breast-feeding is hazardous in developing countries."