The causes of discoloration of health regulations can be roughly divided into four categories:
The first category is people who have had contact history with confirmed cases or asymptomatic infected people in COVID-19, including close contacts, sub-close contacts and close contacts in time and space. The so-called close contact in time and space refers to the key population who may be exposed to more than 1 hour (including delay 1 hour) at the same time, in the same place (a key place where many cases occur or a high-risk place where a single case involves a closed space) and within 250 meters around the onset of a confirmed case or asymptomatic infected person.
The second reason for the color change is that I have been to a high-risk area in COVID-19 (including the cell phone signal under my name).
The third category is that the information reported when reporting the health code is inaccurate.
The fourth category is other people who have been included in the COVID-19 epidemic prevention and control platform for investigation and verification.