Within a few hours after the investigators received the investigation information.

Be sure to check the ground personnel within 2 hours after receiving the investigation information, and put the isolation control in place within 8 hours; Other regional coordination data pushed should be checked and controlled within 24 hours. First, complete the network direct report and transshipment in time. After receiving the positive report of nucleic acid test, all kinds of medical institutions at all levels should complete the direct network report within 2 hours, and transfer the infected person to the designated hospital within 2 hours. The CDC should investigate and verify the report immediately after receiving it, and complete the audit within 2 hours. Any place shall not increase the consultation, evaluation and other procedures without authorization. The second is to carry out epidemiological investigation at the first time. After receiving the direct network report, the disease control institutions in the jurisdiction should immediately start epidemiological investigation, complete the investigation of basic information, onset and treatment, risk factors and exposure history, laboratory testing and other information of cases and asymptomatic infected persons within 24 hours, fill in the case questionnaire, and accurately determine the contact personnel according to the contact mode, contact frequency and contact duration of infected persons with others. The third is to broaden the traceability of traffic control. The survey was supplemented by face-to-face epidemiological survey, visiting attending doctors, consulting cases, supplementary telephone survey, big data tracking, Alipay and WeChat transaction records, and consulting videos. During the investigation, people, things and environment were checked together, and the epidemiological history of the patient 14 days before the onset was inquired in detail, so as to accurately grasp the information such as contact time, mode, frequency, location, protection situation at that time, comprehensively analyze and preliminarily infer the possible sources of infection, and constantly verify the preliminary inference through sampling and testing people, environment and suspicious objects. Search for related cases quickly, so as to find related cases or cluster epidemic symptoms as soon as possible and take timely prevention and control measures.