Immune response to rotavirus vaccines among breast-fed and nonbreast-fed children.

Studies to determine whether breastfeeding protects children against rotavirus diarrhea have not, to date, yielded clear-cut results. Because human breast milk contains measurable and often high titers of neutralizing antibody to rotavirus, it seems likely that some protection should be conferred to breast-fed children1,2. Studies of rotavirus infection in the neonatal period, which is usually asymptomatic, have indicated that breast-fed infants appear to shed less virus, often mixed with antibody, and have lower rates of infection, a finding that was correlated with levels of both S-IgA and antitrypsin activity in breast milk3,4. In older children, investigators failed to document any protection from breastfeeding among cohorts of children studied prospectively in Guatemala5 and Mexico6 or in case-control studies in the United States7 and Bangladesh2; however, significant protection was observed in a case-control study conducted in Buffalo8. The lack of a clear protective effect has raised questions about the methods used to assess the outcome and severity of illness in these studies and has focused investigations on issues related to inoculum size and partial or complete breastfeeding that could obscure a beneficial effect if one were present.