Illness in the classroom

I am very distressed with what is going on in our son's classroom.  He is in regular 1st grade classroom and he is not really very affected with the melas, just some more mild problems, so on the whole he is still healthy.  The 2nd week of school a detailed letter went home to all parents addressing the fact that their is a student in the classroom who is more susceptible to infections(which he is) and that infections can have a serious negative affect on the child.  Specific guidlines were listed as to when to keep your sick child at home.  The school is working well with us and is completely understanding of our concerns in trying to keep our son as healthy as possible and knows we are very concerned in light of the recent death of our daughter, so the issue does not lie with the school.  This week while we had him out for a check-up one day it was reported 6 children were out sick, 2-3 were still in school who were sick and should have not been there and 1 case of confirmed flu, which is being presumed the H1N1, as well as some kids being sent back to school before they were better.  Therefore, since some sick childeren have been sent to school with who know's what (and that's not the point, it is still some kind of infection) we have made the decision to keep our son home the last 3 days so as not to expose him to these obvious infections.  He himself is not ill.  I am becoming frustrated since he is missing out on his education because other parents are not following the guidlines.  We are in the process of talking with the school about this issue and how to resolve it, so I am hoping we can come to some kind of reasonable solution to what will possibly continue to be an issue for the rest of winter.  We can't in good conscience send him to a place where we know there are infected people.  We have unfortunately learned that infections seem to be a major trigger through our experiences with our daughter.  Thus far our son has not been set back by any of the infections, but I feel like a person with mito is kind of a "ticking time bomb".  You never know when something is going to happen and we have know way of knowing just how many mutated mitochondria he has lurking inside his body.

Wondering if anyone else has encountered this with their children in the school environment?

I know it is a lot of rambling.