Level 1: What are the symptoms of a cold in babies? 1. Fever and cold are caused by viruses, which will cause the baby\’s body temperature to rise, usually exceeding 37.5°C. 2. Runny nose When you have a cold, the mucosa in the nasal cavity is stimulated and will secrete a large amount of fluid, causing the nose to become blocked and clear water-like fluid to flow out. 3. Cough