Introduction:COVID-19 remains a concern. Most people are vaccinated, and effective therapeutic interventions for earlier disease stages are available. Epidemiological data were mostly collected during the pre-Omicron time; thus, an update on risk factors for severe COVID-19 is needed.

Objectives:To identify current risk factors for severe COVID-19 among patients with SARS-CoV-2 infection and unplanned admission to Intensive Care.

Methods:Retrospective chart review of all patients admitted to 11 Portuguese ICUs with PCR-proven SARS-CoV-2 infection (February 1st and April 30th, 2022).

Results: We included 305 patients. 194 (63.6%) had severe or critical COVID-19 (S/C). Higher body mass index, immune suppression, frailty, and chronic steroid therapy were more frequent in the S/C group (p<.05 for all). 96 patients had some form of immune suppression, including solid (n=23) or hematological (n=15) malignancies, solid organ transplantation (n= 25), or auto-immune diseases (n=24). All, except solid neoplasms, were significantly more frequent in S/C COVID-19.

In this cohort, non-vaccinated patients (n=77) had a > 4-fold risk of developing S/C COVID-19 (univariate analysis, OR 4.02; 95% CI [2.01- 8.08]). In bivariate analysis, using either immunosuppression, chronic steroid therapy, or the frailty index, this remained significant (p<0.05 for all comparisons).

Conclusions: Frailty index, higher BMI, and chronic steroid therapy are common in patients admitted to intensive care with S/C COVID-19. Immunosuppression poses a heterogenous risk for S/C disease. These patients are often non-vaccinated, which highlights the protection against severe disease afforded by vaccination. Adequate information to citizens is paramount to combat vaccine hesitancy.