Cleveland Clinic researchers identified 484 unique mutations among six strains of SARS-CoV-2 isolates early in the COVID-19 pandemic, finding that the first variants were more deadly than subsequent strains and suggesting that monitoring circulating strains may help predict patient outcomes.Their study, published yesterday in JAMA Network Open, involved sequencing the viral genomes from specimens obtained from 302 COVID-19 patients at Cleveland Clinic from Mar 11 to Apr 22, 2020, and comparing them with those of the original SARS-CoV-2 strain from Wuhan, China.Infection with early virus subgroups, or clades, was associated with higher death rates than later strains (21.4% vs 5.6%). "These findings help explain persistent hospitalization yet