Wondering whether vaccines and breastfeeding mix? Check out this info from Kellymom.com.

http://www.kellymom.com/health/meds/vaccines-bf.html#flu

If I were breastfeeding and considering a vaccination, that would not be helpful at all. It doesn't provide any assurance that it is safe and basically says that the fact that the mother is breastfeeding doesn't affect the efficacy or safety of the vaccination (i.e. for the mother). A couple of the descriptions say that while the live vaccine passes through the breastmilk it isn't know n to cause problems in the infant.
I read nothing reassuring there.