If two nucleic acid tests are done three days later after the critical period of possible contact with confirmed cases and asymptomatic infected persons, and the time interval between the two tests is more than 72 hours, and the results are both negative, the system will remove the yellow code and use the green code instead.
2. The reason why the health code turns yellow:
If you have been active and stayed near the key places where confirmed cases and asymptomatic infected people have stayed, and you may have had contact with confirmed cases and asymptomatic infected people, your health code is listed in the yellow code.