Theoretically, high titers of immunoglobulins in breast milk might reduce the efficacy of the same vaccine; administered to infants. Current evidence shows that when routine childhood vaccines are given according to vaccination schedules, breastfeeding not only does not interfere with the infant’s response to any vaccine but also actually enhances infants’ response to some vaccines.
Breastfed infants are also less likely to have a fever and may less likely to experience anorexia and reduced energy intake after routine childhood immunization than those who are not breastfed. Vaccines come in two general types; inactivated vaccines that contain the antigens of the target organism or live attenuated strains of the organism. Some vaccines are made using recombinant gene technology whereas others consist of killed disease organisms.
There is no evidence or reason to believe that inactivated or recombinant vaccines would harm a nursing infant. Live attenuated vaccines given to the mother could conceivably infect the infant; but most live vaccines do not pass into milk or harm the infant. Two exceptions are yellow fever and smallpox vaccines; which can infect infants and should avoid in nursing mothers.
Vaccinating breastfeeding women
In light of the continuing anti-vaccination movement; a provocative new article provides a comprehensive overview of the potential risks of vaccinating breastfeeding women. The article, which determined that only smallpox vaccine and, in some circumstances yellow fever vaccine, are the only vaccines having the potential to cause harm to infants, is in Breastfeeding Medicine; the official journal of the Academy of Breastfeeding Medicine published.
In Maternal Vaccination and Breastfeeding, reviewed all of the most common types of vaccines; including inactivated and live attenuated types for the unsubstantiated concern that they would cause harm to a nursing infant or interfere with the infant’s response to early childhood vaccinations. Included in the scope of Dr. Anderson’s review are routine vaccines such as influenza, diphtheria, pertussis, and tetanus (DPT); varicella and measles, mumps, and rubella (MMR).
The special risk factors
The article also focuses on vaccines related to exposure or special risk factors; such as hepatitis A or hepatitis B; specialty vaccines including cholera, yellow fever, smallpox, rabies, and typhoid. “As Dr. Anderson concludes in his timely and important article, there are no risks with giving breastfeeding mothers routine and most other standard vaccinations; including measles, and, in fact; there are benefits for both the mothers and infants.
These benefits include the transfer to the infant of maternal antibodies and enhanced antibody response and less vaccine-related fever following infant vaccination, as Dr. Eidelman explains in the accompanying editorial entitled “Guidelines for Vaccinating Breastfeeding Mothers.” Dr. Eidelman further notes that not only is there no harm in administering routine vaccinations to breastfeeding mothers; but one can and should include nursing mothers in any emergency measles immunization campaign, such as the recent emergency declared.