Risk factors for intensive care unit admission and death from COVID-19 in fully vaccinated patients hospitalized for severe COVID-19, Brazil, 2021-2022.

Objectives: To assess factors associated with admission to an intensive care unit (ICU) and death from coronavirus disease 2019 (COVID-19) in fully vaccinated patients with severe COVID-19 in Brazil and the association between ICU admission and death from COVID-19. Methods: This was retrospective study of patients hospitalized for COVID-19 from February 12, 2021 to January 10, 2022 across Brazil who were fully vaccinated against COVID-19 before hospitalization. Outcomes were admission in an ICU for COVID-19 and death from COVID-19. Variables evaluated were: sex; age; self-reported skin color; macroregion; comorbidities; time between full vaccination and onset of symptoms; and time between onset of symptoms and hospitalization. A Poisson regression model was used to estimate crude and adjusted risk ratios. Results: Of 74 991 patients hospitalized for severe COVID-19, 67.28% were ≥ 70 years and 68.32% had at least one comorbidity. Men, patients aged 60-69 years, and patients aged 18-39 years with obesity had the greatest risk of ICU admission. Patients aged 18-39 years with obesity, diabetes, or renal diseases had the highest risk of death from COVID-19. When age and time between onset of symptoms and hospitalization were considered effect modifiers, patients admitted to an ICU 9-13 days after symptom onset in each age category had the greatest risk of death from COVID-19. Conclusion: Although older patients were at greatest risk of ICU admission and death from COVID-19, the difference in the risk of dying from COVID-19 between patients admitted to an ICU and those not admitted was greatest for young adults.