This is a risk communication to some of the people whose trajectories overlap with those of infected people after screening through big data. It does not equate to restricted activity or quarantine. This is because of the "spatial and temporal accompaniment"

If you receive a text message that you are a close contact, then first of all we have to honestly stay at home, do not go anywhere to do self-protection, and try to isolate from the family and then stay in a room, waiting for the arrival of 120.