| Clinical presentation | Description |
| Persistent symptoms | Nasal discharge or cough or both for >10 days without improvement |
| Severe symptoms | Onset with temperature of ≥39°C (102.2°F) and purulent nasal discharge for ≥3 consecutive days |
| Worsening symptoms | Respiratory symptoms (nasal discharge or cough, or both) that worsen after initial improvement, or |
| Onset of new fever or severe headache |
