I would assume that you would need to be careful after your child having any live attenuated vaccines. These vaccines can in some cases still cause disease and include the varicella (chickenpox), rotavirus and measles-mumps-rubella (MMR) vaccines. It's recommended not be around immune-compromised people after having those vaccinations as it can cause infection of the disease.

I would suggest doing whatever you usually do if you child is ill. I don't use MCN's, but I imagine you can sanitise them in the wash (by themselves) with the hottest water possible. I think I've read that the hot setting on dryers sanitises most clothing. And the sun/UV light must be a great sanitiser