This familial cluster transmission indicates that the COVID-19 was transmitted by the asymptomatic carrier, Patient 1 travelling from the epidemic epicenter. The incubation period for Patient 1 was 19 days. The first PCR test was negative, indicating a false negative result. Further study regarding asymptomatic transmission is required.

University of Michigan - Ann Arbor

Family cluster study of asymptomatic transmission: A 20 year-old woman from Wuhan, China (Patient 1) traveled to Anyang on January 10, 2020 and met with Patient 2 and Patient 3. On January 13, she visited a hospitalized relative with Patients 2-6. At this time, there were no reported cases of COVID-19 at the Anyang District Hospital. Patient 1 was isolated and tested/monitored for the following symptoms: temperature/fever, gastrointestinal symptoms, respiratory symptoms (cough/sore throat), chest CT, C-reactive protein, lymphocyte count. RT-PCR testing was negative on January 26, positive on January 28, and negative on February 5/8.
Patients 2-6 developed COVID-19. 

Presumed Asymptomatic Carrier Transmission of COVID-19 in China

Bai, Y., Yao, L., Wei, T., Tian, F., Jin, D. Y., Chen, L., & Wang, M. (2020). Presumed asymptomatic carrier transmission of COVID-19. Jama, 323(14), 1406-1407.
https://jamanetwork.com/journals/jama/article-abstract/2762028
doi:10.1001/jama.2020.2565

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