The duration of viral fever in babies is mostly around three to five days. Common viral infections usually have a fever of around three days, for influenza virus, adenovirus and other infections the duration is on the longer side, usually around five days.
Viral infections are generally self-limiting and self-healing, so antivirals or antibiotics are generally not needed. The natural course of viral disease is usually about one week, so fever symptoms usually last up to one week.
Therefore, if your baby has a fever for less than three days, is in good spirits and has no other serious symptoms, it can be initially determined to be a viral infection, so antiviral or antibiotic drugs are generally not required; if your baby has a fever for more than five days, and the fever does not go away, and the spirit is poor or irritable, drowsy, vomiting and other conditions, you should consult a doctor for further examination to make a definitive diagnosis.