Transmission potential of the novel coronavirus (COVID-19) onboard the diamond Princess Cruises Ship, 2020

Mizumoto, Kenji; Chowell, Gerardo

The observed and estimated daily number of cases among passengers and crew members from day 1 to day 29 (January 20, 2020eFebruary 17, 2020) are shown in Fig. 1 . The total number of cases for all and by type (passengers and crew members) were estimated at 187.0 (95%CrI: 163.8, 212.3), 127.1 (95%CrI: 107.8, 148.9) and 59.6 (95%CrI: 47.3, 74.0), respectively. For comparison, the number of reported cases for all and by type were 197, 149 and 48 respectively. The corresponding percentage coverage of the 95%CrI of estimated data for observed data, the number of days where the model 95% CrI overlapped with the observed data, is 54% (15/28) for all, and 50% (14/28) and 43% (12/28) for passenger and crew, respectively. The time-dependent reproduction number for all and by type are presented in Fig. 2 . For all, R t rapidly increased at around day 12 (January 31, 2020) and reached its maximum with the value of 11.2 (95%CrI: 7.5, 16.2) at day 19 (February 7, 2020). R t for passengers presented a similar pattern with the value of 12.1 (95%CrI: 8.2, 17.2) at day 19 (February 7, 2020), while R t for crew members only shows slight fluctuations with the largest value reaching 1.56 (95%CrI: 0.07, 7.55) at day 23 (February 11, 2020).