Taiwan Severe Asthma Biologic Registry

Inclusion Criteria: * Provision of informed consent prior to any study specific procedures. * Patient should be reviewed as well as confirmed by the National Health Insurance Administration (NHIA) or by the study board member as a Severe Asthma case. * Female and male aged over 18 years old. * Patients who are treated either with omalizumab, mepolizumab, or benralizumab after January 1, 2020. Exclusion Criteria: * Lack of informed consent for participation. * History of Biologic usage before January 1, 2020, should be ruled out. * The washout period should be at least 12 months. In other words, the enrolled patients should have no experience in receiving a biological treatment or in participating relative clinical trial before his/her biologic initiation. * Comorbid pulmonary diseases (e.g.: Chronic Obstructive Pulmonary Disease, Bronchiectasis, Pulmonary Fibrosis, etc.) or risk factors (e.g.: smoking or environmental exposure, etc..) that could be associated with pulmonary or systemic diseases, other than Asthma.