7. the subject is willing and is able to meet all the requirements of the study. * Exacerbation : Exacerbation means worsening of two or more of the following main symptoms for at least 2 consecutive days: dyspnea, volume of sputum; Sputum purulence o worsening of any main symptom along with one of the following symptoms for at least 2 consecutive days: sore throat; Cold ( nasal congestion); Fever without any other cause; Cough; Wheezing