Generally, key personnel who may be related to COVID-19 are divided into categories A, B, C, D and E5, and corresponding regulatory measures are taken according to different types. Class A personnel are close contacts of COVID-19 positive cases diagnosed by nucleic acid detection, Class B personnel are close contacts of Class A personnel, Class C personnel are those whose health code is yellow, Class D personnel are those in closed areas, and Class E personnel are those who have returned from abroad.
For Class B personnel in COVID-19, it is usually necessary to conduct centralized isolation for 2 1 day, and then conduct home isolation for 7 days. The starting time of isolation is calculated from the last contact date with Class A personnel. During the isolation period, nucleic acid detection is carried out every day, and two copies of nucleic acid are taken the day before the isolation is lifted. After the quarantine expires, the nucleic acid test is negative, and the CDC can issue a notice to lift the quarantine. After the end of home isolation, the community will notify the release of isolation.