Why did the epidemic prevention and control office send me other people's information?

At present, most of the information mainly comes from the following three aspects: first, the investigation letter sent by the disease control department or the higher administrative department, including close contacts (referred to as secret contacts), close contacts of close contacts (referred to as sub-secret contacts), general contacts and key risk personnel. The second is to close the list of people involved in the epidemic in key areas pushed by big data; The third is the process adjustment of the case or close contact. The sending time of investigation information is uncertain, which may be in the daytime or in the early morning. After receiving the investigation letter, the CDC staff need to complete the process adjustment or information bridge verification immediately. If the information in the investigation letter is incomplete and there is no contact information, the public security system needs to cooperate.