Figure 1.

Transmission dynamics of patients at the superspreading event associated with COVID-19 in a hospital. The designated wards for isolation of COVID-19 cases were 9B, 13H and ICU. The cluster involved four hospital staff (patients 2–5), two families (patients 6 and 9) of the index case (patient 1), one accompanying person for an un-infected in-patient (patient 7), and one in-patient who stayed in the same ward (patient 8). Patients 2, 3, and 8 may acquire infection earlier than symptom onset of the index case. Patient 2 was a cleaner and performed cleansing work for the bed next to the bed of Patient 1 at the emergency room on February 14. Patient 3 was a nurse who cared patient 1 on February 16, and she also cared an un-infected in-patient (patient 7's family) from February 21 to February 23. Patient 4 was a nurse who cared patient 1 on February 19. Patient 5 was a nurse practitioner who wore a surgical mask to swab patient 1 for a rapid influenza diagnostic test on February 24. She joined the team to care patient 1 for several days before the cluster. Patient 6 was patient 1's daughter who accompanied patient 1 during her admission in the ward 5C. She was asymptomatic throughout the entire course. Patient 7 accompanied her un-infected husband during his admission to ward 5C for treatment before the cluster. Patient 9 was the index case's son who stayed in the ward 5C for only one day on February 16. Patient 8 was admitted to the ward 5C from February 14 to February 20 for radiofrequency ablation of liver tumor. Patient 9 was tested negative twice before the end of quarantine on March 3. He developed cough on March 6, and a third testing was positive for SARS-CoV-2 on March 10. Except the asymptomatic patient 6, the serial intervals (in parentheses) of the infected were: patient 2 (0), patient 3 (−1), patient 4 (6), patient 5 (6), patient 7 (4), patient 8 (0), and patient 9 (16).