Why does Sichuan Tianfu Health Link have a high-risk residential area?

Close contact. Why does Sichuan Tianfu Health Link live in a high-risk area because of close contact? It is recommended to isolate for three days. "Health Link" is a real-name authentication based on social security card (resident health card), which can realize cross-hospital mobile medical payment and service application, so that patients don't have to queue up at the hospital window to pay medical expenses, and young people can also help their families pay remotely on their mobile phones.