Objectives  To analyze clustering characteristics of 2019 novel coronavirus disease (COVID-19) epidemic in Henan province.

  Methods  The information on all COVID-19 cases registered in Henan Province Public Health Emergency Management Information System from January 23 to February 25, 2020 were collected from case reporting cards and reports for surveys on individual and clustering incidence and analyzed with descriptive statistics.

  Results  Totally 256 clusterings of COVID-19 cases were identified in 103 counties/districts of 18 prefectures across Henan province, involving 59.88% of all the cases reported during the period. Of the 790 cluster cases, 708 (89.62%) were confirmed cases and 82 (10.38%) were asymptomatic infections; 269 (34.05%) were imported cases and 521 (65.95%) were cases with local infection. The highest number of clusterings were reported during 3 – 4 February, 2020 and more clusterings were identified in the 5 prefectures of the province. Among the cluster epidemics identified, 222 (86.72%) involved 2 – 4 cases; 27 (10.5%) involved 5 – 9 cases, and 7 (2.73%) involved 10 or more cases. The majority (222, 78.90%) of the identified cluster epidemics occurred in family settings and mainly involved non-imported cases. The median of incubation period in 7 days.

  Conclusion  The 2019 novel coronavirus is of high contagiosity and could cause large-scale cluster epidemic. Comprehensive measures should be adopted early to prevent the transmission of the virus.