How long does influenza B fever last in children?

The duration of fever in children with influenza B (type B influenza) varies depending on individual differences and the severity of the illness. 1. After infection with influenza B, children typically experience fever for about 3 to 5 days, which corresponds to the period of active viral replication in the body. 2. The length of fever is closely related to the child's physical condition and immune resistance. Children with stronger immunity may have a shorter fever duration, while those with weaker constitutions may require more time to recover. 3. With timely and appropriate treatment—such as antiviral medications like oseltamivir phosphate granules or ribavirin granules—the viral load in the body gradually decreases, leading to a shorter fever period. If a child experiences persistent high fever or worsening symptoms, prompt medical attention is recommended.