A cough after a viral infection can linger for weeks while the airway settles. That is common and usually harmless. The difficulty is telling it apart from a cough that is telling you something else.
The three-week mark
A cough that continues past three weeks is worth assessing — not because it is necessarily serious, but because by that point the cause is usually something identifiable: allergy, post-nasal drip, reflux or airway sensitivity.
Signs that should not wait
- Coughing blood
- Breathlessness at rest or on mild exertion
- High fever with chest pain
- Unintended weight loss alongside the cough
Why antibiotics often do not help
Most persistent coughs are not bacterial. If allergy or reflux is driving it, an antibiotic course will not change the pattern — and the cough returns as soon as it finishes.
