J.R.
Day care and school are just germ factories - it's so hard to keep them well! Build up his immunity with lots of sleep and good diet. Ask the day care (nicely)what their policies are to help prevent the spread of germs (handwashing regimens, etc.). They probably have things in place but just in case, it might prompt them to do a brief review with their staff. Do you have a humidifer on your furnace? If not, run that vaporizer as much as you can, even if you are moving it from room to room. If the cough is not loose (bringing up mucus) listen to his back. One particularly troublesome year, my daughter had undiagnosed pneumonia and they kept treating it as a cold until my mom did this and pronounced it pneumonia and she was right! Good luck, I know they don't like to give antibiotics any more so he is building up his own resistance but I know it's tough on both of you!