In reading about thrush, I came across a bit about chicken pox that is
interesting. This is from a unit on Candidiasis and Breastfeeding by
Amir, Hoover, and Mulford.IT is a xerox copy that I have.
"Herpes zoster(shingles) may cause pain in one breast preceded several
days by a rash which commonly looks like papules (red bumps), sometimes
vesicles(small blisters), and occasionally bullae(large blisters).
DIRECT CONTACT MAY CAUSE CHICKEN POX IN THE BREASTFEEDING CHILD.
(emphasis mine)

Ellen in Pittsburgh

Sounds like if a mom has chicken pox her babe could get it from contact
with the blisters.