Isolation of rubella virus in milk after postpartum immunization.

SEVERAL STUDIES ~' ~ have shown that successful rubella vaccination of rubella-susceptible mothers in the immediate postpartum period does not lead to the appearance of detectable levels of rubella H A l antibodies in the children. The absence of antibodies is not related to the type of feeding (breast or formula) and no attempts have been made to detect rubella virus in the mother 's milk. Recently, we studied a postpartum vaccinee and her breast-fed infant for a period of 15 months. Rubel la virus was isolated from breast milk and from a pharyngeal swab from the infant. Specific humoral and cell-mediated immune responses measured serially reflected an unusual exposure to rubella vaccine. We report this experience: (1) to document the presence of rubella vaccine virus in breast milk, (2) to describe the infant 's provocative immune responses, and (3) to add reassurance concerning the safety o f breast-feeding after postpartum rubella immunization.