Epidemiology of COVID-19 Outbreak on Cruise Ship Quarantined at Yokohama, Japan, February 2020

• Published in: Emerging infectious diseases Vol. 26; no. 11; pp. 2591 - 2597
• Main Author: Expert Taskforce for the COVID-19 Cruise Ship Outbreak
• Format: Journal Article
• Language: English
• Published: United States U.S. National Center for Infectious Diseases 01.11.2020; Centers for Disease Control and Prevention
• Subjects: 2019 novel coronavirus disease; Adult; Age; Asymptomatic; Betacoronavirus; Body temperature; Causes of; Coronavirus Infections - epidemiology; Coronavirus Infections - transmission; Coronaviruses; COVID-19; cruise ship; Disease Outbreaks - statistics & numerical data; Disease transmission; Disease Transmission, Infectious - statistics & numerical data; Distribution; Epidemics; Epidemiology; Female; Fever; Humans; Illnesses; Infectious diseases; Japan; Japan - epidemiology; Laboratories; Male; Medical screening; Middle Aged; Occupational Diseases - epidemiology; Occupational Diseases - virology; Pandemics; Passengers; Patients; Pneumonia, Viral - epidemiology; Pneumonia, Viral - transmission; Public health; Quarantine; Quarantine - statistics & numerical data; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Ships; Travel; Japan; Hong Kong; COVID-19; cruise ship; epidemiology; SARS-CoV-2; viruses; severe acute respiratory syndrome coronavirus 2; Japan; zoonoses; 2019 novel coronavirus disease; coronavirus disease; quarantine
• DOI: 10.3201/eid2611.201165
• ISSN: 1080-6040; 1080-6059

To improve understanding of coronavirus disease (COVID-19), we assessed the epidemiology of an outbreak on a cruise ship, February 5-24, 2020. The study population included persons on board on February 3 (2,666 passengers, 1,045 crew). Passengers had a mean age of 66.1 years and were 55% female; crew had a mean age of 36.6 years and were 81% male. Of passengers, 544 (20.4%) were infected, 314 (57.7%) asymptomatic. Attack rates were highest in 4-person cabins (30.0%; n = 18). Of crew, 143 (13.7%) were infected, 64 (44.8%) asymptomatic. Passenger cases peaked February 7, and 35 had onset before quarantine. Crew cases peaked on February 11 and 13. The median serial interval between cases in the same cabin was 2 days. This study shows that severe acute respiratory syndrome coronavirus 2 is infectious in closed settings, that subclinical infection is common, and that close contact is key for transmission.