Breastfeeding and Vaccines

Vaccines in general

Breastfeeding does not affect the safety of vaccinations for mom or baby.

Although breastfeeding passes many immune factors to baby, breastfeeding should not be considered a substitute for immunization. Research indicates that when breastfed babies are vaccinated, they will produce higher levels of antibodies in comparison to formula fed babies.

According to the US Centers for Disease Control document General Recommendations on Immunization (February 8, 2002) [PDF version for printing]:

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“Neither inactivated nor live vaccines administered to a lactating woman affect the safety of breast-feeding for mothers or infants. Breast-feeding does not adversely affect immunization and is not a contraindication for any vaccine. Limited data indicate that breast-feeding can enhance the response to certain vaccine antigens. Breast-fed infants should be vaccinated according to routine recommended schedules.

“Although live vaccines multiply within the mother’s body, the majority have not been demonstrated to be excreted in human milk. Although rubella vaccine virus might be excreted in human milk, the virus usually does not infect the infant. If infection does occur, it is well-tolerated because the viruses are attenuated. Inactivated, recombinant, subunit, polysaccharide, conjugate vaccines and toxoids pose no risk for mothers who are breast-feeding or for their infants.”

Information on specific vaccines

Anthrax Vaccine

Per the US Centers for Disease Control document Use of Anthrax Vaccine in the United States (December 15, 2000):

“No data suggest increased risk for side effects or temporally related adverse events associated with receipt of anthrax vaccine by breast-feeding women or breast-fed children. Administration of nonlive vaccines (e.g., anthrax vaccine) during breast-feeding is not medically contraindicated.”

CDC Update: Interim Recommendations for Antimicrobial Prophylaxis for Children and Breastfeeding Mothers and Treatment of Children with Anthrax (November 16, 2001) discusses the use of antibiotics for prevention of anthrax in breastfeeding mothers and children.

Chicken Pox Vaccine

“Whether attenuated vaccine VZV is excreted in human milk and, if so, whether the infant could be infected are not known. Most live vaccines have not been demonstrated to be secreted in breast milk. Attenuated rubella vaccine virus has been detected in breast milk but has produced only asymptomatic infection in the nursing infant. Therefore, varicella vaccine may be considered for a nursing mother.” ACIP, Prevention of Varicella, pp. 19-20.

Flu Vaccine

Many moms wonder specifically about the flu vaccine. This, like other vaccines, can be administered to nursing mothers. According to Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP), from the US Centers for Disease Control:

“Influenza vaccine does not affect the safety of mothers who are breastfeeding or their infants. Breastfeeding does not adversely affect the immune response and is not a contraindication for vaccination.”

There are currently two forms of the flu vaccine:

The intranasal (nasal mist) form of the influenza vaccine (trade-name FluMist™) is an attenuated (weakened) live vaccine. It is approved for use only in healthy people between the ages of 5 and 49 years. Per the CDC, “CDC’s Advisory Committee on Immunization Practices (ACIP) today voted that live attenuated influenza vaccine (LAIV), also known as the “nasal spray” flu vaccine, should not be used during the 2016-2017 flu season. ACIP is a panel of immunization experts that advises the Centers for Disease Control and Prevention (CDC). This ACIP vote is based on data showing poor or relatively lower effectiveness of LAIV from 2013 through 2016.”
The standard, injectable form of the flu vaccine is an inactivated (killed) vaccine.

The CDC indicates that either form of the vaccine is acceptable for a breastfeeding mother, as long as she otherwise meets requirements for receiving the vaccine. However, as of 2016-2017, the CDC is no longer recommending the nasal spray flu vaccine.

US Centers for Disease Control has general information on the current Flu Season and the CDC maintains a Weekly Flu Map for the US.

MMR Vaccine

Per the US Centers for Disease Control document Measles – Q&A about Disease & Vaccine:

“Breast feeding does not interfere with the response to MMR vaccine, and your baby will not be affected by the vaccine through your breast milk.”

Smallpox Vaccine

The US Centers for Disease Control, recommends that breastfeeding mothers not get the smallpox vaccination. There is no evidence that vaccinia virus is transmitted in breast milk (see the above CDC information on vaccinations in general). However, the concern is that the breastfed baby, due to close proximity to the mother, might come into physical contact with the vaccination site. Note that current guidelines recommend that any person who has been vaccinated with this vaccine (breastfeeding or not) avoid close physical contact with babies under a year old for 2-3 weeks (until the scab falls off) — this would presumably affect all parents who hold, feed, care for, cuddle or sleep with their babies.

Following are US Military guidelines for preventing exposure to the vaccinia virus via contact with the vaccination site. Per the US Military Clinical Policy for the DoD Smallpox Vaccination Program ( Nov. 26, 2002) [from pp. 5-6 “Care of the Vaccination Site”]:

“Vaccinia virus can be cultured from the site of primary vaccination beginning at the time of development of a papule (i.e., two to five days after vaccination) until the scab separates from the skin lesion (i.e., 14 to 21 days after vaccination). During that time, care must be taken to prevent spread of the virus to another area of the body or to another person by inadvertant contact. Disease transmission from intact scabs is unlikely, but high-risk individuals may be vulnerable to scab particles. Historically, the rate of spread of vaccinia virus to contacts is quite rare, about 27 cases per million vaccinations.”

“The most important measure to prevent inadvertent contact spread from smallpox vaccination sites is thorough hand washing (e.g., alcohol-based waterless antiseptic solution, soap and water) after any touching of the vaccination site.”

“Minimizing close physical contact with infants less than one year of age is prudent until the scab falls off. If unable to avoid infant contact, wash hands before handling an infant (e.g., feeding, changing diapers) and ensure that the vaccination site is covered with a porus bandage and clothing. It is preferable to have someone else handle the infant. Smallpox vaccine is not recommended for use in a nursing mother in non-emergency situations.”

Smallpox Vaccine: Pregnancy and Breastfeeding from the CDC

CDC Smallpox Information

US Military information on smallpox vaccination