Why do space-time companions have to install an alarm when they spend 72 hours twice?

What is a time companion? Li Menglei, deputy director of the Emergency Office of the Provincial Center for Disease Control and Prevention, said that space-time companion is one of the risk groups in COVID-19, which refers to people who stay in a space with confirmed cases and asymptomatic infected people for more than a certain period of time.

Relevant personnel explained that the person who received the text message was a "time companion". According to Zhengzhou's current policy, "time-space companion" needs to do nucleic acid twice within 72 hours, and the interval between two tests needs 24 hours. The test results should be reported to the community where they live. If the nucleic acid test is not carried out as required, the personal health code will be changed to red.

The code that appears after scanning on WeChat is the scene code. After this code changes color, it will be tested for nucleic acid as required, and then it can be changed back to green code through the community. The code displayed on Alipay is Henan Health Code. Once the color changes, you need to do three nucleic acid tests as required. After that, click the "transcoding" application in the lower right corner of Henan Health Code, and after submitting the negative nucleic acid certificate online, the relevant staff will review it. After approval, the code will change back to green code within 7 working days.