How do you tell your family the rules?

So I'm worried about family members kissing and touching our babies face and hands when he arrives, especially since it'll be the end of September and that's around the time that illness starts to spread. I keep telling my Husband that this is what I want and don't want, and he just says it's going to happen. I don't think he realizes that our son is not going to have an immune system and does not get shots until he is a little older. He thinks that I am worrying about everything(which I am) and that things will just work out by itself. This our rainbow and I want to do everything I can to make sure he is okay.

I don't want a bunch of people over to our home in the first few weeks because we need to figure out a schedule and I don't want the over stimulation. I'm just not sure how to lay out the ground rules for what I want without trying to be rude.

I know that if I say something my MIL is most likely to have some kind of comment on how she knows best and all that. She is constantly complaining that she is sick and works with children all day so who knows what she is bringing back.

So back to the question. How do I lay down the ground rules and things that I want for our newborn?