An investigation of a family COVID-19 cluster

ObjectiveTo investigate epidemic characteristics of a family cluster of COVID-19, and to provide reference in improving the criteria for exclusion diagnosis and medical observation of close contacts.

MethodsField epidemiological method was used to investigate the cases and close contacts of a family cluster of COVID-19 in Pudong New Area.Descriptive analysis was conducted on epidemiological data.Real-time fluorescence quantitative RT-PCR was used to detect 2019-nCoV nucleic acid in the respiratory tract specimens.

ResultsThere were two confirmed cases and one suspected case in the family cluster.The source of infection was Case 1 with a living history in Wuhan, Hubei Province.Case 2 and Case 3, as close contacts, received 14-day medical observation in a centralized isolation site.Case 2 showed symptoms 4 days after the onset of Case 1, and the diagnosis of COVID-19 was excluded after two negative nucleic acid tests during the isolation period.However, after the expiration of isolation, Case 2 was diagnosed positively for COVID-19 and Case 3 was suspected first and then excluded.

ConclusionDaily close contact is critical for COVID-19 transmission and is the major cause of family clustering.Once the close contacts show symptoms, diagnosis should be made by combining the results of nucleic acid test, chest CT test, serological test, etc.We suggest to grade the risk of infection for close contacts, and to strengthen the standard of medical observation for close contacts with high risk of infection.