Did they "end up in the hospital" or did they go to the hospital to get a diagnosis? I live in a city, and my PCP is in the local hospital. "seasonal illness symptoms" sounds FAR more like they were just sick and went to the doctor, like anyone else would. For medicine.
And what exactly does "hospital" mean in China? I know in India a hospital can basically be a small clinic, not unlike an urgent care center in the USA.