[Effectiveness of precise prevention and control strategies of dynamic zero COVID-19 in Ningbo, Zhejiang province].

Objective: To evaluate effectiveness of the precise prevention and control strategies of dynamic zero COVID-19 in Ningbo, Zhejiang province. Methods: Based on the incidence data of COVID-19 and case epidemiological survey report in Ningbo in December 2021, the incidence curve of COVID-19 was generated and a dynamics model was developed to estimate the case number of under different intervention measures. The basic reproduction number (R0) and real-time reproduction number (Rt) were calculated to evaluate intervention effect. Results: A total of 74 cases of COVID-19 had been confirmed in Ningbo as of 17 December, 2021. The R0 was estimated to be 4.3. With the strengthening of prevention and control measures, the Rt showed a gradual downward trend, dropping to below 1.0 on December 11 and 0.4 on December 14. The model fitting results showed that the actual case number was close to the estimated case number (76 cases) when the effectiveness of intervention was 90%. The number of cases decreased by 98.4% compared with that if no intervention was taken. Conclusion: The precise prevention and control strategies of dynamic zero COVID-19 have obvious effect, which can facilitate the rapid control of COVID-19 epidemic in Ningbo.