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.