How about making sure that every classroom has a good supply of kleenex and a can of Lysol? Make signs to encourage kids to wash hands, use kleenex when they cough and sneeze, and not to share drinks or food. Reinforce the school's illness policy and maybe even expand it a little to encourage parents to keep those sick children home. Maybe a little education on nutrition might even be in line so people go into flu season as healthy as possible.