Viruses (e.g., respiratory syncytial virus (RSV), enterovirus, influenza A and B, parainfluenza, coronavirus, and rhinovirus) cause approximately 90% of acute bronchitis cases. Bacterial infections are relatively uncommon, accounting for only 1%–10% of cases.[1][2]
What causes acute bronchitis?
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•Last Updated: May 16, 2025
Acute bronchitis is primarily caused by viruses, which account for approximately 90% of cases, and common examples include RSV, influenza, and rhinovirus. Bacterial infections are rare and make up only 1% to 10% of cases.