Air Recirculation Role in the Spread of COVID-19 Onboard the Diamond Princess Cruise Ship during a Quarantine Period

HIGHLIGHTS

Infection rate in cabins with previous case was not statistically different than those without.
Age of subject was found not to be a confounding factor.
Conflicting results from previous studies of this outbreak are largely explainable.
Airborne transmission through the HVAC system could explain the virus spread on the ship.
Recirculated air and inadequate air filtration likely increased airborne transmission.