_:vb50941693 . _:vb50941693 "A chronic asthma that is characterized by severity with symptoms two or fewer days per week, nighttime awakenings two or fewer times per month, use of short-acting beta agonist for symptom control several times per day and extremely limited normal activity."^^ . _:vb50941693 . _:vb50941693 . _:vb50941693 . _:vb50941693 "url:https://www.aafp.org/afp/2009/0501/p761.html"^^ .