Abstract:

Objective To investigate and analyze a family-cluster case caused by imported coronavirus disease 2019(COVID-19) from abroad and provide evidence for its prevention and control. Methods We conducted epidemiological investigation, medical isolation and observation on a male patient with suspected COVID-19 (index patient, got suspected on February 4, 2020) and his close contacts in Huating, Pingliang City of Gansu Province. Their throat swabs were collected for nucleic acid test of SARS-CoV2 (real-time PCR). Results A total of 40 close contacts were identified through the investigation. The index patient was diagnosed on February 7, and then 6 confirmed patients were discovered from his close contacts: his mother, wife, second eldest sister and little daughter who returned home on January 26, and his eldest sister as well as his father-in-law. This family cluster case was finally deemed to be caused by a confirmed patient returning to Xingping City from Wuhan City to the aunt (Mrs Wu) of the returning child, and then from Mrs Wu to the other returnees. Frequent gathering meals and overnight stays with the index patient and the other 5 close contacts were the main reasons for this cluster outbreak. Three generations of cases were generated in this family cluster. The total secondary attack rate was 17.1% (7/41), and the second-generation secondary attack rate was 35.7% (5/14) while the third-generation secondary attack rate was 3.7% (1/27). Conclusion This epidemic was a family cluster case caused by imported COVID-19 patients from outside the current city. During the COVID-19 spreading period, gatherings should be reduced and close contact should be avoided. In addition, epidemiological investigations, isolation and nucleic acid testing of patients and their close contacts should be initiated timely which can quickly break the chain of transmission and confirm the diagnosis promptly.

Key words: Coronavirus disease 2019 (COVID-19), Disease outbreak, Contact tracing, Disease impact status investigation