Abstract: Objective To analyze the isolation medicine observation for close contacts of New Coronavirus Pneumonia(NCP)in Jinan City. Methods All information of close contacts who were isolated due to COVID-19 was collected from the epidemiological survey during the epidemic of COVID-19 in Jinan City from January 24 to March 1, 2020. The softwares of Excel 2016 and SPSS16.0 were used to sort and analyze data. Results A total of 1 455 close contacts were isolated for medical observation. A total of 28 cases of COVID-19 infection were detected, including 25 cases of confirmed NCP and 3 cases of positive asymptomatic. The attack rate was 1.92%. 1 455 close contacts were mainly distributed in Lixia District(40.69%), Licheng District(16.98%)and Shizhong District(8.38%). The detection rate of COVID-19 was different among close contacts who had a different relationship with the primary case(χ²=180.34, P<0.001), among which close-connected cases had the highest incidence of close contacts(15.38%). There were 13 primary cases of close contacts of COVID-19 infection, of which 5(38.46%)had a travel history in Wuhan City, 1(7.69%)had a travel history in Hubei province, and 3(23.08%)had traveled outside Hubei Province, the remaining 4 cases(30.77%)had no history of field travel. There were 23 of the close contacts who were managed by Jinan City developed disease, of which 8(34.78%)had developed disease before the close observation period, and the median time interval from onset to isolation was 5 days. There were 15 patients(65.22%)who developed disease during the isolation observation period with a median interval of 3 days. The median time of 23 close contacts from the beginning of the medical observation period to the diagnosis was 2 days, and the median time from onset to diagnosis was 3 days. There were 23 of the close contacts who were managed by Jinan City developed disease, of which 17 patients(73.91%)was ordinary type, and 6 patients(23.09%)were mild. Conclusion There are positive and asymptomatic persons in close contact with COVID-19 infection cases. Screening should be conducted for imported personnel and close contacts who come from key areas. Comprehensive prevention and control measures should be taken as soon as possible. Personal protection measures for home isolation of high-risk groups should be strengthened.

Key words: New coronavirus pneumonia, Close contacts, Isolated medical observation, Attack rate, Effect evaluation