The recent Hantavirus infection outbreak linked to the expedition vessel MV Hondius has revived memories of the early cruise ship outbreaks during the start of the COVID-19 pandemic.

Although both incidents involve international passengers, quarantines, and respiratory illness aboard ships, health experts say the similarities largely end there.

Cruise Ships as Early Warning Zones

Cruise ships have long been considered high-risk environments for infectious disease outbreaks because passengers live in close quarters, share dining and recreation spaces, and travel internationally within short periods of time.

During the early COVID-19 outbreak in 2020, ships such as the Diamond Princess became global symbols of rapid viral spread. Hundreds of passengers aboard the vessel became infected after the coronavirus spread extensively among guests and crew during quarantine near Yokohama.

The current hantavirus situation aboard the MV Hondius has also triggered international monitoring, but investigators say the dynamics appear very different.

COVID-19 Spread Rapidly at Sea

COVID-19 spread efficiently between people through airborne respiratory transmission. Cruise ships amplified that risk dramatically:

• Shared ventilation systems
• Crowded indoor activities
• International passenger movement
• Delayed testing in the early pandemic

By early 2020, multiple cruise ships worldwide reported outbreaks, helping demonstrate how contagious the coronavirus had become.

The Diamond Princess outbreak alone eventually recorded more than 700 infections, becoming one of the earliest major international clusters outside mainland China.

Hantavirus Outbreak Appears More Limited

The current hantavirus outbreak linked to the MV Hondius involves a far smaller number of cases and appears connected to the rare Andes strain of hantavirus.

Unlike COVID-19:

• Hantavirus is not known for efficient airborne human transmission
• Most infections originate from rodent exposure
• Sustained community spread has not been observed

Health officials believe the ship environment may have contributed to close-contact exposure among passengers, but experts stress that the outbreak does not currently show the explosive transmission patterns seen with COVID-19 aboard cruise ships.