You can usually tell if you have the flu by your child’s symptoms, laboratory tests, and other methods. 1. Symptoms: Children with influenza usually have respiratory symptoms such as cough and runny nose, in addition to nausea, vomiting and other digestive symptoms are also more obvious, and can be accompanied by mild diarrhea. Compared with ordinary infections, children with influenza have heavier systemic symptoms, muscle aches and pains, and it is not easy to get rid of fever, and the fever goes up again a few hours after taking antipyretics. 2. Laboratory tests: Rapid pathogenicity tests on throat swabs or nasal swabs are usually directly detectable, whether it is influenza A virus, influenza B virus, or parainfluenza. There may be other ways to determine whether your child has influenza. If you suspect that your child has influenza, it is recommended that you go to the hospital promptly for early and regular treatment.