Maternal antibodies in breast milk protect the child from enterovirus infections

: Sadeharju K, Knip M, Virtanen SM, Savilahti E, Tauriainen S, Koskela P, Akerblom HK, Hyoty H

Publisher: AMER ACAD PEDIATRICS

: 2007

: Pediatrics

: PEDIATRICS

: 119

: 5

: 941

: 946

: 6

: 0031-4005

DOI: https://doi.org/10.1542/peds.2006-0780(external)

OBJECTIVE. Enterovirus infections are frequent in infants and may cause severe
complications. We set out to assess whether breastfeeding can protect against these
infections and whether such an effect is related to maternal antibodies in breast
milk or in the peripheral circulation of the infant.
METHODS. One hundred fifty infants who were prospectively followed up from birth
were monitored for enterovirus infections. The duration of breastfeeding was
recorded, and maternal breast milk and blood samples were regularly taken at
3-month intervals for the detection of enterovirus antibodies and RNA. Maternal
serum was available from early pregnancy, delivery, and 3 months postpartum.
RESULTS. Enterovirus infections were frequent and were diagnosed in 43% of infants
before the age of 1 year and in 15% of the mothers during pregnancy. Infants
exclusively breastfed for 2 weeks had fewer enterovirus infections by the age of
1 year compared with those exclusively breastfed for 2 weeks (0.38 vs 0.59
infections per child). High maternal antibody levels in serum and in breast milk
were associated with a reduced frequency of infections. This effect was seen only
in those infants breastfed 2 weeks, indicating that breast milk antibodies mediate
this effect. Enterovirus RNA was not found in any of the breast milk samples.
CONCLUSIONS. These results suggest that breastfeeding has a protective effect against
enterovirus infections in infancy. This effect seems to be mediated primarily by
maternal antibodies in breast milk.