…This study simulated a seven-day cruise with 2,000 passengers and 800 crew members, and each day was assumed to be a port day. When there was an index passenger on the cruise ship, people in restaurants and crew cabins had a higher infection risk than those in other locations. Increasing the ventilation rate of HVAC systems in the restaurants and crew cabins was effective. Installing UVGI devices in all HVAC systems reduced the attack rate by 87.8%. When HEPA filters were installed in the HVAC systems, the efficacy was only slightly lower than that of UVGI devices. The use of surgical masks by crew members serving in restaurants, bars, lounges, or small public places resulted in only a moderate reduction in the attack rate. Quarantining the index passenger and his/her roommate at Day 2 and succeeding days did not greatly reduce the attack rate.
The infection risk from an index crew member was higher than that from an index passenger, because the crew member had potential contact with all the cohorts on the ship.
