Herpes simplex virus (HSV) is a common viral infection. Genital herpessores can be transmitted to the breast. It is most likely that HSV is passed from mom to baby by direct contact with a herpes lesion. To determine if a sore is caused by HSV, culturing will be necessary.

Most sources advise that if the HSV lesion can be covered, so the baby does not come in contact with it, breastfeeding can continue. If the sore iswhere the baby will come in contact with it, you will need to express yourmilk from that breast, discarding it until the lesions dry. You can continueto nurse from the unaffected breast. With any active herpes infection, themother should pay careful attention to hand washing, clean covering of activelesions, and no kissing or fondling of the baby until the lesions are dried.(Quinn, PT, Lofberg, JV., Med J Aust, 1978)

It is important to note that HSV infection during an infant's first three weeks of life can be fatal. If you have HSV and are planning to breastfeed, it is very important to discuss your situation with a knowledgeable health care provider.