Will Falconer, DVM Moderator
No "pup in a bubble" is necessary once you start the nosodes. Get them out in the world, they are safe and this is prime time for socialization, a rather short window that lays the foundation for good behavior throughout life.
Parvo and distemper are the only diseases capable of killing a youngster (beside rabies, depending on where/how you live) and shedded viruses won't be a problem worth worrying about.