Acute bronchitis and clinical outcome three years later: prospective cohort study.

Acute bronchitis is a common disorder usually assumed to be caused by a viral infection with no beneficial effect resulting from antibiotic treatment. We examined whether acute bronchitis in a healthy individual should be regarded as an isolated event or a predictor of chronic lung disorders that has not yet clearly manifested itself clinically—that is, as bronchial hyperresponsiveness, asthma, or chronic bronchitis.