Clinical Characteristics and Outcomes of Vaccinated VS Non-Vaccinated Critically Ill COVID-19 Patients: Retrospective Observation Study.

Objective: We aim to identify the clinical characteristics and outcome of vaccine breakthrough infection in critically ill COVID-19 patients and to compare the clinical course of disease between vaccinated and non-vaccinated patients.

Methods: A retrospective review of all adult patients aged ≥18 years admitted to the ICU in King Fahd Hospital of the University in Saudi Arabia with positive COVID-19 RT-PCR test between the period of January 1st to August 31st, 2021, were included. The recruited patients were grouped in to "vaccinated and non-vaccinated group" based on their immunization status.