Transmission of Yellow Fever By Breastfeeding After Administration of a Live Virus Vaccine to the Mother

 

Features:

(1) There is a history of a live virus yellow fever vaccine being administered to the mother.

(2) The mother breastfeeds her infant.

(3) The infant presents with yellow fever.

(4) The virus infecting the infant is the vaccine strain.

 

Factors modifying the risk:

(1) IgG antibodies against YF in the mother transmitted transplacentally during the pregnancy

 

Clinical findings in the infant:

(1) fever

(2) refusal to nurse

(3) irritability

(4) seizures

(5) evidence of meningoencephalitis

 

Breast milk can be tested for YF virus.

 

Differential diagnosis:

(1) yellow fever from mosquito bite (would not be the vaccine strain)

(2) accidental vaccination of the infant with yellow fever virus (includes YF contamination of another vaccine)