Legal basis: Article 2 of novel coronavirus Prevention and Control Plan (Eighth Edition): Multi-channel monitoring and early warning. According to the principle of combining point with surface and combining infectious disease monitoring system with other departments' monitoring systems, we will carry out multi-channel monitoring of people, things and environment. 1. Monitoring of medical staff. Medical staff of all kinds of medical institutions at all levels, especially primary medical and health institutions, should raise their awareness of finding and reporting COVID-19's cases, and carry out COVID-19 nucleic acid test on all patients with fever and other suspected patients without fever, cases of unexplained pneumonia and severe acute respiratory infection among hospitalized patients, all newly admitted patients and their accompanying personnel. 2. Monitoring occupational groups at risk. Health monitoring and weekly full-time nucleic acid detection shall be carried out for the supervision and employees of imported cold chain food, management and service personnel of centralized isolation places, direct contact personnel of imported goods at ports, medical staff of designated medical institutions for cases in COVID-19, medical staff of fever clinics and emergency departments of comprehensive medical institutions, employees of international vehicles, ship drivers and other foreign ship operators, and frontline personnel of entry-exit, customs and market supervision systems. Found fever, dry cough, fatigue, sore throat, decreased sense of smell (taste), diarrhea and other symptoms. Go to a medical institution with a fever clinic (consulting room) for nucleic acid detection in time. Weekly sampling nucleic acid detection was conducted for farmers' markets, other departments of comprehensive medical institutions, express delivery, transportation and other specific service places and industry personnel. 3. Health monitoring of key populations. Do a good job in health monitoring of people in high-risk areas, medical observers discharged from COVID-19, and immigrants brought into community management. Found fever, dry cough, fatigue, sore throat, decreased sense of smell (taste), diarrhea and other symptoms. Go to a medical institution with a fever clinic in time for nucleic acid detection. 4. Cargo and environmental monitoring. Sampling nucleic acid detection of imported cold chain foods and their processing, transportation, storage and sales places; Sampling nucleic acid detection is carried out on imported goods from high-risk countries and low-temperature transportation environment at land, sea and air ports, as well as their cargo holds, containers, carriages, containers and cargo storage places, and the detection frequency and sampling quantity can be increased under low-temperature conditions in winter. Medical institutions with fever clinics and large agricultural products wholesale markets with cold chain food in cities regularly carry out nucleic acid detection. Regularly carry out sewage monitoring in large-scale processing places where frozen products are imported by sea. 5. Monitoring of key institutions. After there are 1 cases of confirmed cases or asymptomatic infected persons in this county (district), do a good job in daily health monitoring of personnel in key institutions such as pension welfare institutions, psychiatric hospitals, supervision places, crowded places (such as production workshops, shopping malls and supermarkets, training institutions), kindergartens and schools, and find fever, dry cough, fatigue, sore throat and odor. 6. Centralized monitoring in isolated places. During the opening of centralized isolation places, environmental nucleic acid detection should be carried out regularly. 7. Pathogen monitoring. The first or early cases in the local epidemic, key cases with epidemiological relevance to early cases, local cases with unknown infection source, imported cases, imported articles and related environmental positive samples were sequenced and compared to dynamically understand the genetic variation of the virus and find the infection source in time. 8. Analyze early warning. Strengthen cross-departmental information sharing, carry out comprehensive analysis of epidemic monitoring and risk judgment, put forward risk assessment results and early warning suggestions, and timely release epidemic information and health risk tips to the society.