An interesting paper published in the Journal of Infectious Diseases details the discovery that human breast milk has antiviral activity against the hepatitis C virus (HCV).
Approximately 5-10% of deliveries by HCV positive women result in perinatal transmission of HCV to the child. Transmission is related to HCV viremia, HIV co-infection, prolonged membrane rupture, and intrapartum exposure to maternal blood. Breast milk, though it contains the virus, is not thought to be a major risk.
This paper adds further weight to the safety of HCV positive mothers breastfeeding their children. In this study, researchers incubated HCV--at concentrations 1000x higher than that found in breast milk--with breast milk from HCV uninfected women. Infectivity after incubation with breast milk was reduced 2-3 fold for all genotypes of the virus. Further experimentation confirmed that the mechanism underlying the antiviral effect was due to free fatty acids that disrupt the viral envelope (see graphic).
In an accompanying editorial, Ravi Jhaveri of UNC writes: "After reading this article, when we clinicians next encounter an HCV-infected patient that just delivered a healthy infant and wants to breastfeed, we have yet another reason to say 'Breast is Best'."