Title : Clinical features of adult, hospitalized, non-vaccinated COVID-19 patients during the omicron variant surge in Japan
Abstract:
Background: The mortality of SARS-CoV-2 infection in non-vaccinated patients is still thought to be high despite the appearance of the omicron subvariant. A total of 36 adult, non-vaccinated patients who were hospitalized with SARS-CoV-2 infection during the omicron variant surge were included in this study.
Case series: Severity of illness at admission was mild, moderate, and severe in 0 (0%), 29 (80.6%), and 7 (19.4%) patients, respectively, and three (3/36=9.1%) patients died. The patients who died were as follows. (Case 1) A 64-year-old man on hemodialysis developed severe pneumonia caused by SARS-CoV-2 infection. His pneumonia did not worsen, but he developed septic shock on Day 5 with a catheter-related blood stream infection due to methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum beta-lactamase (ESBL)-producing Escherichia coli. (Case 2) An 87-year-old man with a history of esophageal cancer had moderate pneumonia at admission, but suddenly developed massive brain hemorrhage on Day 6. (Case 3) A 94-year-old man with a history of brain infarction and atrial fibrillation had moderate pneumonia on admission. His pneumonia was improving, but he died on Day 7 of acute renal failure and suspected recurrent brain infarction.
Conclusions: These data and cases suggest that non-vaccinated patients showed high mortality, especially elderly male patients with underlying diseases. They died due to reasons other than respiratory failure and/or pneumonia, and impairment of blood vessels, especially in the brain, heart, and kidneys, by SARS-CoV-2 infection was thought to have occurred, though the omicron variant has generally low pathogenicity.
