The transmission pattern and clinical course identified from 417 patients with COVID-19 pneumonia in Shenzhen, China: a retrospective and observational study

Abstract Background To help government formulating epidemic control strategies and spreading Shenzhen's experience. Methods 417 patients admitted to hospital with confirmed COVID-19 infection between 19 January and 21 February 2020 in Shenzhen, China.Observational study of COVID-19 outcomes using quality-assured public data from website of Shenzhen Municipal Health Commission and a COVID-19 diagnosis and treatment fixed-point hospital to transmission patterns and associated factors of sporadic and clustered COVID-19 cases and its critical time courses.Results We Compared the characteristics of clustered and non-clustered cases, found the clustered cases differed significantly from non-clustered cases in age and exposure history. Moreover, we analyzed the time intervals between symptom onset and recovery for three clinical conditions and different stages of transmission patterns, found the time intervals between illness onset and hospital discharge for all patients were no more than 30 days. Finally, we analyzed disease severity conditions, severe patients spent 4-5 more days of hospitalization and medical intervention than moderate and mild patients did.Conclusions The study confirms that severe patients spent 4-5 more days of hospitalization and medical intervention than moderate and mild patients did. Our results also provided robust evidence that timely and effective prevention measures were the key to quickly cut the transmission chains and prevent the transition from clustered transmission pattern to community transmission pattern.