Continued breastfeeding increases HIV-free survival for infants in Zambia

June 2009

The Zambia Exclusive Breastfeeding Study randomized HIV-positive mothers to wean their infants at four months (intervention) or to continue breastfeeding for as long as they wished (control). Although nearly 40% of the intervention mothers did not follow the instructions to stop breastfeeding at four months, analysis showed that there was no difference in HIV-free survival between those in the intervention group that adhered and those that did not and continued breastfeeding beyond four months. In a new paper published in PLOS One, the authors conducted a secondary analysis, based on the previous study findings, to investigate whether maternal disease severity modified the relative risks of HIV infection and death associated with adherence to the intervention. Infants of women with less severe disease who stopped breastfeeding at four months were more than two times as likely to die or acquire HIV compared to infants who breastfed longer. Conversely, early weaning among women with more advanced disease had a protective effect. Among infants whose mothers had higher CD4 counts (less severe disease), breastfeeding continued to have a protective effect until the age of 15 months, with those weaned earlier more than three times as likely to die or become HIV-infected. The authors conclude that continued breastfeeding has a protective effect among women with CD4 counts above about 300 cells/ul and that appropriate initiation of anti-retroviral therapy among women with more advanced disease would reduce the risk of postnatal transmission and enable safe continuation of breastfeeding.

Differential Effects of Early Weaning for HIV-Free Survival of Children Born to HIV-Infected Mothers by Severity of Maternal Disease