Objective To analyze the epidemiological characteristics of local COVID-19 epidemic in Zhejiang province in spring of 2022.
Methods The epidemiological data of local COVID-19 epidemic in Zhejiang from March 3 to May 8, 2022 were collected, and descriptive epidemiological method were used for analysis.
Results A total of 262 clusters of COVID-19 cases were reported in this epidemic in 71 counties (districts) in 11 prefectures (municipality) in Zhejiang, a total of 668 symptomatic cases and 866 asymptomatic cases were diagnosed. Local spatial autocorrelation analysis showed the clustering hot spots in Jiashan county, Pinghu and Haining cities, Linping, Yuhang, Gongshu, Shangcheng and Wucheng districts. Up to 72.90% of COVID-19 case clusters were caused by the imported cases from Shanghai; the duration of the virus spread in clusters with more than 50 cases ranged from 7 to 15 d, and the dynamic basic reproduction number (Rt) was kept below 1 for about 10 d.
Conclusions This round of epidemic mainly occurred in Jiaxing and Hangzhou due to local SARS-CoV-2 transmission caused by imported cases from other provinces; the earlier the Rt declined below 1, the smaller the epidemic scale and the short the epidemic duration.