Remember that we use iv acyclovir in tiny babies, even premature ones.
As always, weigh the risk of one alternative against the risk of the
other.  What is the risk to the baby of the mother taking acyclovir?
The baby will get only a tiny percentage of what the mother gets.  The
baby will also get breastmilk.

There are risks associated with artificial feeding.  I have a 7 page
list of articles.  These are known.

When you add everything up, it seems to me the mother can take her
acyclovir and breastfeed.  But, give her the information, let her know
how important breastfeeding is, and let her make her decision.  If you
do not believe breastfeeding is of any importance, she will stop
breastfeeding.  If you do, she will breastfeed.

Jack Newman, MD, FRCPC