Objective  To analyze prevalence characteristics of clustering cases of 2019 novel coronavirus disease (COVID-19) in Liaoning province for providing evidences to effective containment of COVID-19 epidemic.

  Methods  We collected the information on all reported COVID-19 cases from the day of first case report (January 22, 2020) till February 21, 2020 and analyzed the data with descriptive statistics.

  Results  Among a total of 121 COVID-19 cases reported during the 31 days in Liaoning province, totally 26 epidemic clusters were identified and all the clusters occurred in family settings. The epidemic clusters involved 81 cases in 10 prefecture-level regions, accounting for 66.9% of the all cases reported. For the clusters identified, the number of cases was between 2 and 6 for each cluster. Of all the cluster cases, 76.5% were aged 30 – 69 years. For all the cluster cases, the male to female ratio was 0.84 : 1 and the incubation period ranged 1 – 19 days, with a median of 8.0 days. Of all the initial cases of the clusters, 16 (61.5%) reported the history of travelling in Hubei province (the epicenter of COVID-19) within 14 days before the onset of the disease; 7 (26.9%) reported the history of travelling in other provinces; 8 (30.8%) were severe or critical severe cases. Main clinical manifestations of the cluster cases were fever (occurred in 63.0% of the cases), fatigue (24.7%), dry cough (23.5%), headache (11.1%), and muscle soreness (11.1%).

  Conclusion  In Liaoning province, the majority of the COVID-19 cluster cases were imported cases and occurred in family settings, suggesting that the control of family transmission of COVID-19 is the key to the containment of the epidemic.