AbstractBackgroud: Since 2021, all outbreaks of COVID-19 within mainland China have been associated with imported cases from abroad. The outbreak in Putian, Fujian province, occurred without obvious loopholes in the implementation of epidemic prevention, indicating loopholes in the current epidemic prevention strategies in mainland China. The loopholes should be identified and the epidemic prevention strategies should be improved as soon as possible.Methods: Is there a need to further extend the medical observation period and community health surveillance period for key populations? Is there a need to increase the number of nucleic acid screenings? Is there a need to change the methods of extraction of nucleic acid screening samples? Is there a need to expand the scope of the population for routine epidemic prevention surveillance? The analysis of these questions would contribute to the improvement of the COVID-19 epidemic prevention strategies.Results: There are larger outbreaks following the current intensive isolation medical observation period and community health surveillance period, the phenomenon shows that the loopholes in the assessment of cross-infection risk and health surveillance in China's current COVID-19 prevention and control strategies, especially during health surveillance after the entry of undetected infected individuals into the community when they emerge during isolation medical observation, and during health surveillance in the community for those who regain positive status after case cure.Conclusions: The key points to improve epidemic prevention strategies includ that a scientific and rational assessment around the mean incubation period, cross-infection risk, and surveillance efficiency of COVID-19, and updating routine epidemic prevention surveillance measures for key populations, recently cured patients of COVID-19, and immersion populations. Keywords: COVID-19, epidemic prevention strategy, incubation period, cross-infection