Vaccination protects against mortality and intensive care unit (ICU) admission in hospitalized patients with COVID-19

Background: The objective of this study was to investigate the impact of COVID-19 vaccination on mortality, intensive care unit (ICU) admissions, and organ protection in hospitalized COVID-19 patients. Methods: : This retrospective, single-center cohort study included hospitalized COVID-19 patients with confirmed vaccination status and chest imaging data from July 2021 to February 2022. Outcomes such as mortality, ICU admission, and organ damage were evaluated using clinical data, chest CT scans, and laboratory parameters. Our study used logistic regression and advanced statistical methods, including LASSO regression to analyze differences in hospitalized COVID-19 patients based on vaccination status, adjusting for significant demographic parameters and confounding variables, with a focus on ICU admissions and mortality. Results: : The study encompassed 167 patients (69% male, mean age 58 years, 95% CI [55; 60], 42% fully vaccinated) for data analysis. After adjusting for confounding factors, vaccinated hospitalized COVID-19 patients exhibited a significantly reduced relative risk for mortality (RR: 0.46, 95% CI [0.13; 0.99]) and ICU admissions (RR: 0.59, 95% CI [0.28; 0.89]) compared to their non-vaccinated counterparts. Additionally, vaccinated COVID-19 patients demonstrated significantly fewer pulmonary lesions (Cohen’s d: -0.38, 95% CI [-0.74; -0.02]), reduced instances of COVID-19-induced coagulopathy (RR: 0.26, 95% CI [0.00; 0.88]), and lower AST (Cohen’s d: -0.40, 95% CI [-0.69; -0.12]) and ALT levels (Cohen’s d: -0.45, 95% CI [-0.73; -0.17]). The number needed to treat to prevent one ICU admission among hospitalized COVID-19 patients was found to be as low as four. The protective effect of COVID-19 vaccination seems to amplify with the severity of the disease. The vaccination's protective effect was particularly pronounced in preventing ICU admissions among middle-aged patients (around 55 years old) (RR: 0.64, 95% CI [0.32; 0.99]). Type 2 diabetes emerged as a significant risk factor for increased mortality (OR: 3.02, 95% CI [1.24; 7.34]) and ICU admission (OR: 3.09, 95% CI [1.33; 7.57]). Conclusions: : COVID-19 vaccination may mitigate the risk of mortality, severe disease progression, and damage to the pulmonary, liver, and coagulation systems in hospitalized COVID-19 patients, particularly among middle-aged patients around 55 years old.