Yellow Fever Vaccine

Drug Levels and Effects:

Summary of Use during Lactation:

Yellow fever encephalitis has been reported in breastfed newborns whose mothers received yellow fever vaccine. Administration of yellow fever vaccine to breast-feeding women should be avoided except in situations where exposure to yellow fevervirusescannot be avoided or postponed. Infants under 6 months appear to be at an increased risk of encephalitis from the vaccine and should not be vaccinated. Infants over 9 months of age should be vaccinated themselves if they will be traveling with their mother to a yellow-fever endemic area.[1][2] Exposure to yellow fever vaccine via breastmilk would not increase the risk to an infant who receives the vaccination him/herself.

Drug Levels:

Maternal Levels.

Relevant published information was not found as of the revision date.

Infant Levels.

Relevant published information was not found as of the revision date.

Effects in Breastfed Infants:

One probable case of yellow fever vaccine-associated neurologic disease (YEL-AND) was reported in a 38-day-old infant whose mother was vaccinated 24 days earlier with the Brazilian-manufactured yellow fever vaccine 17D (probably the 17-DD strain). The infant was exclusively breastfed. Although it was not possible to determine if the breast milk was the mode of transmission, no other plausible cause was identified.[3]

A woman who was exclusively nursing her newborn received 17DD yellow fever vaccine on day 15 postpartum. Eight days later her infant developed fever, irritability and refused to nurse. One day later, the infant developed seizure-like activity. The infant was hospitalized and had periods of somnolence and irritability and required intravenous anticonvulsants to control seizures. An MRI was consistent with encephalitis. Yellow fever-specific IgM antibodies were detected in serum and CSF. Laboratory examination of the infant's cerebrospinal fluid confirmed the presence of a viral strain identical to the vaccine. This was the first case of laboratory-confirmed, breastfeeding-associated transmission of 17DD yellow fever vaccinevirusfrom a recently vaccinated mother.[1]

A Canadian mother had received a yellow fever vaccination (probably the 17D-204 strain) when her breastfed (extent not stated) infant was 10 days of age. At 5 weeks of age, the infant developed focal seizures on alternating sides, poor appetite, and vomiting following a 2-day history of fever and irritability. The infant's serum was positive for yellow fever and the cerebrospinal fluid was positive for yellow fever antigen, but negative for yellow fevervirus. Although the authors could not entirely rule out other causes, they judged the adverse reaction to probably be caused by yellow fever vaccine transmitted via breastmilk to the infant.[4]

Possible Effects on Lactation:

Relevant published information was not found as of the revision date.


1. Anon. Transmission of yellow fever vaccinevirusthrough breast-feeding --- Brazil, 2009. MMWR Morb Mortal Wkly Rep. 2010;59:130-2. PMID:20150888
2. Staples JE, Gershman M, Fischer M, Centers for Disease Control and Prevention (CDC). Yellow fever vaccine: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR. 2010;59 (RR-7):1-27. PMID:20671663
3. Traiber C, Amaral PC, Ritter VR, Winge A. Infant meningoencephalitis probably caused by yellow fever vaccinevirustransmitted via breastmilk. J Pediatr (Rio J). 2011;87:269-72. PMID:21461453
4. Kuhn S, Twele-Montecinos L, Macdonald J et al. Case report: probable transmission of vaccine strain of yellow fevervirusto an infant via breast milk. CMAJ. 2011. PMID:21324845

Substance Identification:

Substance Name:

Yellow Fever Vaccine

Drug Class:

  • Vaccines

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

    Disclaimer:Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.