Mumps IgA antibodies are not absorbed from human milk.

We measured mumps virus specific IgA antibodies in the sera of preterm infants after a feeding period on human milk rich in such antibodies. In full-term infants the possibility of absorption was determined from the content of these antibodies in the child's mother's milk, an umbilical cord blood sample and a later serum sample. No absorption of IgA antibodies was found.