Nagging worked to get my oldest to stop biting her nails.
I have explained to the girls that this fall/winter there is going to be a virus that can make people sick. I've explained the importance of keeping their hands away from their faces. My oldest washes hands like we do in the hosptal (she turns off the faucet with a paper towel).
Take a deep breathe and just be proactive but not paranoid. Personally I'm not going to shake hands at church like they do (I think they are going to stop that during the flu season though). If I"m standing behind someone that looks sick I change lanes....things like that. I work with immunosuppressed patients so I would feel horrible if I accidently gave them something while I didn't know I was contagious.
How old is your son?
You could also have items on hand that you and your family might need. I have made sure I have ibuprofen and acetaminophin for adults and children.
I work with someone who says she is going to stop checking out books from the library for these months because she doesn't know who has hacked on them. I do love the library so I don't think I'll be doing that. I am being more thoughtful though and not licking my finger to turn the pages.