Preparation for the Quarantine of The Diamond Princess Cruise Ship for COVID-19 in Japan: Study Design.

BACKGROUND: Japan has experienced the large-scale quarantine on the cruise ship, the Diamond Princess, in an attempt to infectious control for the novel coronavirus (SARS-CoV-2) in February 2020.

OBJECTIVE: We will describe the medical activities and the difficulties of the cruise ship quarantine.

METHODS: Reverse Transcription-Polymerase Chain Reaction (RT-PCR) tests for SARS-CoV-2 were performed on all 3,711 persons (2,666 passengers and 1,045 crew).

RESULTS: Six-hundred ninety-six (18.8%) reported positive, of which 410 (58.9%) were asymptomatic. We also confirmed that 54% of the asymptomatic patient with RT-PCR-positive had lung opacities when they have a chest CT (Computed tomography). There were many difficulties onboard, such as creating a dividing traffic line between infectious and non-infectious passengers, finding hospitals and transportation willing to accept these patients, transporting individuals, language barriers, and supporting daily life. As of March 8, thirty-one patients (4.5% of RT-PCR test positives) were hospitalized requiring ventilator support or intensive care, and seven patients (1.0% of RT-PCR test positives) died.

CONCLUSIONS: There were several difficulties in terms of large-scale quarantine and medical support on the cruise ship. We need to prepare the patients' transfer and admitting hospitals when disembarking the passengers. We recommend treating the crew as same as the passengers with the infection control principle. We must make a plan ahead to protects the travelers and passengers from the emerging infectious diseases on cruise ships.