Tertiary contact vaccinia in a breastfeeding infant

On May 4, 2003, a US Army soldier received primary smallpox vaccination and experienced a primary uptake reaction at the inoculation site on days 6 through 8. The vaccinee reported observing all of the standard precautions to avoid household spread. In mid May, his breastfeeding wife developed vesicles on both areolas. On May 29, their infant daughter developed a papule on her philtrum. Contact vaccinia was confirmed by positive polymerase chain reaction and culture for vaccinia of both the maternal and infant lesions. This is the first documented case of inadvertent contact vaccinia transmission from a mother to her infant through direct skin-to-skin and skin-to-mucous membrane contact while breastfeeding. The mechanism of transfer from the vaccinee to the spouse is uncertain. This report demonstrates that breastfeeding infants living in close contact with smallpox vaccinees are at potential risk for contact vaccinia, even if the vaccinee is not the breastfeeding mother, and highlights the need for special precautions to prevent secondary transfer to breastfeeding mothers.