US passenger wave to reporters as they leave the Daikaku Pier Cruise Terminal in Yokohama port, next to the Diamond Princess cruise ship, with people quarantined onboard due to fears of the new COVID-19 coronavirus, at on February 17, 2020. - Americans began leaving a quarantined cruise ship off Japan on February 17, 2020, to board chartered flights home as the number of new coronavirus cases diagnosed on the vessel jumped to 355. (Photo by Behrouz MEHRI / AFP)

US passenger wave to reporters as they leave the Daikaku Pier Cruise Terminal in Yokohama port, next to the Diamond Princess cruise ship, with people quarantined onboard due to fears of the new COVID-19 coronavirus, at on February 17, 2020. - Americans began leaving a quarantined cruise ship off Japan on February 17, 2020, to board chartered flights home as the number of new coronavirus cases diagnosed on the vessel jumped to 355. (Photo by Behrouz MEHRI / AFP)

US passenger wave to reporters as they leave the Daikaku Pier Cruise Terminal in Yokohama port, next to the Diamond Princess cruise ship, with people quarantined onboard due to fears of the new COVID-19 coronavirus, at on February 17, 2020. - Americans began leaving a quarantined cruise ship off Japan on February 17, 2020, to board chartered flights home as the number of new coronavirus cases diagnosed on the vessel jumped to 355. (Photo by Behrouz MEHRI / AFP)

A US passenger waves to reporters while arriving at the Haneda Airport, in Tokyo on February 17, 2020 after disembarking in Yokohama from the Diamond Princess cruise ship, where people are quarantined onboard due to fears of the new COVID-19 coronavirus. - Americans began leaving a quarantined cruise ship off Japan on February 17, 2020, to board chartered flights home as the number of new coronavirus cases diagnosed on the vessel jumped to 355. (Photo by Kazuhiro NOGI / AFP)

A US passenger thumbs up to reporters while arriving at the Haneda Airport, in Tokyo on February 17, 2020 after disembarking in Yokohama from the Diamond Princess cruise ship, where people are quarantined onboard due to fears of the new COVID-19 coronavirus. - Americans began leaving a quarantined cruise ship off Japan on February 17, 2020, to board chartered flights home as the number of new coronavirus cases diagnosed on the vessel jumped to 355. (Photo by Kazuhiro NOGI / AFP)

Buses with US passengers on board arrive at the Haneda Airport, in Tokyo on February 17, 2020 after disembarking in Yokohama from the Diamond Princess cruise ship, where people are quarantined onboard due to fears of the new COVID-19 coronavirus. - Americans began leaving a quarantined cruise ship off Japan on February 17, 2020, to board chartered flights home as the number of new coronavirus cases diagnosed on the vessel jumped to 355. (Photo by Kazuhiro NOGI / AFP)

Buses with US passengers on board arrive at the Haneda Airport, in Tokyo on February 17, 2020 after disembarking in Yokohama from the Diamond Princess cruise ship, where people are quarantined onboard due to fears of the new COVID-19 coronavirus. - Americans began leaving a quarantined cruise ship off Japan on February 17, 2020, to board chartered flights home as the number of new coronavirus cases diagnosed on the vessel jumped to 355. (Photo by Kazuhiro NOGI / AFP)

Buses with US passengers on board arrive at the Haneda Airport, in Tokyo on February 17, 2020 after disembarking in Yokohama from the Diamond Princess cruise ship, where people are quarantined onboard due to fears of the new COVID-19 coronavirus. - Americans began leaving a quarantined cruise ship off Japan on February 17, 2020, to board chartered flights home as the number of new coronavirus cases diagnosed on the vessel jumped to 355. (Photo by Kazuhiro NOGI / AFP)

US passengers imbark in a plane at the Haneda Airport, in Tokyo on February 17, 2020 after disembarking in Yokohama from the Diamond Princess cruise ship, where people are quarantined onboard due to fears of the new COVID-19 coronavirus. - Americans began leaving a quarantined cruise ship off Japan on February 17, 2020, to board chartered flights home as the number of new coronavirus cases diagnosed on the vessel jumped to 355. (Photo by Kazuhiro NOGI / AFP)

US passengers imbark in a plane at the Haneda Airport, in Tokyo on February 17, 2020 after disembarking in Yokohama from the Diamond Princess cruise ship, where people are quarantined onboard due to fears of the new COVID-19 coronavirus. - Americans began leaving a quarantined cruise ship off Japan on February 17, 2020, to board chartered flights home as the number of new coronavirus cases diagnosed on the vessel jumped to 355. (Photo by Kazuhiro NOGI / AFP)

US passengers queue to imbark in a plane at the Haneda Airport, in Tokyo on February 17, 2020 after disembarking in Yokohama from the Diamond Princess cruise ship, where people are quarantined onboard due to fears of the new COVID-19 coronavirus. - Americans began leaving a quarantined cruise ship off Japan on February 17, 2020, to board chartered flights home as the number of new coronavirus cases diagnosed on the vessel jumped to 355. (Photo by Kazuhiro NOGI / AFP)