My 2.5 year old son has just joined play school one month back. Since the day he has joined the school he is infected with severe cough and cold, congestion in his chest. At times fever also comes. Our doctor suggested nebulizer with levolin 0.63, but when we stop giving nebulizer after 5 days course as prescribed by the doctor, he again gets cough and cold. What to do in this situation? Other kids in school are completely fine. Before joining school also he used to get cold and cough every second month. What should I do?