A Major Outbreak of COVID-19 in the Diamond Princess Cruise Ship (preprint)

The COVID-19 pandemic broke out in Wuhan, China, and declared an international public health emergency by the World Health Organization in 2019. It mainly manifests as symptoms of respiratory infections, and severe cases can cause pneumonia and death. The Diamond Princess cruise ship outbroke cluster infection outside China during the early pandemic. The incident occurred on February 1, 2020, and an 80-year-old Hong Kong man was diagnosed with COVID-19. The cruise docked in Yokohama, Japan, for 14 days on-board quarantine; however, cluster infection outbroke rapidly. The results show that after 14 days of quarantine, 634 (17.1%) cases were diagnosed with a total of 3,711 population, and 328 (51.7%) cases were asymptomatic. As of April 24, 2020, 712 cases have been diagnosed and 14 deaths have occurred. A cumulative mortality rate reaches 1.96%. Using a nonlinear least-squares curve fitting with Microsoft Excel Solver, we obtain the parameters of the SIR mathematical model of infectious disease and the reproduction number (R0) of the COVID-19 outbreak is 2.37±0.26. Without an emergency evacuation plan, the total infection rate will reach 88.47%. These data show “only one” COVID-19 case could still outbreak cluster infection on large cruise ships. The possible causes and countermeasures are discussed. 

Epidemiological characteristics of imported and domestic COVID-19 cases in Taiwan: a retrospective study (preprint)

Background: This study aimed to elaborate Taiwan’s epidemiological characteristics of 2020 COVID-19 in human, temporal, and geographical dimensions. Methods: Big data for cases from January to May 2020 were obtained from the public database of Taiwan Centers for Disease Control (CDC) in June 2020. The data were used to analyze and compare differences, correlations, and trends in human, temporal, and geographical characteristics of imported and domestic COVID-19 cases.Results: During the study period, 443 cases were confirmed, with a mortality rate of 1.6%. The epidemiological features indicated that most cases (87.6%) were imported. No difference was observed between sexes, but significant differences were observed in age groups (p = 0.002). The age group of 20¬–29 years accounted for the highest proportion of imported cases (40.7%), with an odds ratio (OR) of 2.748, whereas the age group of 50–59 years had the largest proportion of domestic cases (23.6%, OR = 2.770). March 2020 displayed the highest proportion of imported cases (78.1%, OR = 4.278). A significant difference was observed in different regions (p = 0.003), with northern Taiwan exhibiting the highest proportion of both imported and domestic cases (63.4% and 80.0%); in particular, domestic cases in northern Taiwan had an OR of 2.309. Conclusion: This is the first report comparing domestic and imported cases of COVID-19 from surveillance data from the Taiwan CDC during January-May 2020. The study also highlights the importance of longitudinal and geographically extended studies in understanding the implications of COVID-19 transmission for Taiwan’s population.