Perhaps a cruise ship demographic factor was fewer pre-existing health issues than we'd see in a randomly chosen age cohort of similar size? Co-morbidity of ot

Perhaps a cruise ship demographic factor was fewer pre-existing health issues than we'd see in a randomly chosen age cohort of similar size? Co-morbidity of other diseases and COVID-19 seems to correlate with higher case mortality rates. This would predict higher case mortality in assisted living homes, which has been found in the Washington state cluster.