Abstract: The COVID-19 epidemic raises major public health security issues.As a metropolis with high population density and great population mobility,Shenzhen has great challenges in public health prevention and control because of the risk of imported transmission,which might lead to widespread community explosive epidemics.By analyzing local COVID-19 epidemiological characteristics and transmission,and actively exploring epidemic rules and key points of prevention and control,Shenzhen established "key population screening + case isolation treatment + contact isolation medical observation,follow-up management" as the core of accurate prevention and control strategy,supplemented by wearing masks,delayed resume work resumption,maintain social distance and schooling community control as the integrated strategy.In confirmed cases of COVID-19,screening and management of close contacts has shown that the time from symptom onset to isolation has been shortened.Extensive follow-up screening and isolation management strategies have promoted early detection and isolation of cases and effectively reduced the risk of community transmission.We established a mathematical model of importation risk,evaluated the importation risk of our city and study and judged the city's tolerance for prevention and control,therefore we could timely adjust targeted strategies.We carried out monitoring and follow-up for discharged patients with recurrent positive of SARS-CoV-2 RNA,and assessed their risk of transmission,which helped us formulate a follow-up management plan and work guidelines.The implementation of the accurate prevention and control strategy and measures of "screening,detection,isolation,management and extensive tracking" has effectively controlled the COVID-19 epidemic in Shenzhen within 40 days after the epidemic spread,which has provided successful experience for the accurate and effective control of the COVID-19 epidemic around the world,especially in a megacity.

Key words: Coronavirus disease 2019, Prevention and control strategy, Evaluation