A family clustering of coronavirus disease 2019 caused by asymptomatic infection

ObjectiveTo analyze a family clustering of coronavirus disease 2019 （COVID-19） associated with the exposure to an asymptomatic case， and to provide evidences of developing strategies for COVID-19 prevention.

MethodsEpidemiological investigation was conducted on a COVID-19 family cluster （1 confirmed case and 2 asymptomatic cases）. The specimens of the cases were tested for 2019 novel coronavirus nucleic acid with real-time fluorescence quantitative polymerase chain reaction.

ResultsThe clustering epidemic occurred in a family. Two asymptomatic cases B and C （B’s son） had Wuhan residential history. After arrival in Beijing on January 24， 2020， B stayed in his mother's house. One family member A （B’s mother） developed the disease on February 7， 2020， while the other two family members D and E （B’s wife and brother） did not develop the disease， and they were managed as close contacts.

ConclusionThis family COVID-19 clustering is induced by the exposure to an asymptomatic case. Identification of asymptomatic cases is very important for the control of COVID-19 epidemic.