In April 2002, it was reported that a non-Shanghai resident had never been to Shanghai and was quarantined because his health code turned red after receiving a phone call from the Shanghai mobile phone number.
Those with abnormal health code can bring the commitment letter of health code change application, the travel code that has not been to the middle and high risk area, and the nucleic acid test certificate within 48 hours to the district (county) or street (township) epidemic prevention agency to make representations.