Turan, AtakanÖğüt, HamdiVarol, Aylin AyyıldızKoca, NizameddinBozkurt, Hayri2026-02-082026-02-0820252149-3189https://doi.org/10.18621/eurj.1632009https://hdl.handle.net/20.500.12885/4858Objectives: This study aimed to assess the effectiveness of different vaccination regimens using two distinct SARS-CoV-2 vaccines against mortality risk and the need for intensive care unit (ICU) admission among hospitalised patients. Methods: The single-centre hospital-based retrospective cohort study was performed with adult COVID-19 patients in a tertiary-level hospital between March 2020 and September 2022. The associations between patients’ demographics and clinical features, vaccine status and regimens, in-hospital mortality, and need for ICU admission were evaluated using multivariable regression analyses. Results: During the study period, 2,373 patients were included. Mortality among unvaccinated patients was 85.0%, which was significantly lower in vaccinated groups (P<0.001), particularly with BNT162b2 than with Sinovac. Vaccination reduced mortality and ICU admission rates, with higher efficacy observed with increased vaccine doses and BNT162b2 regimens. Multivariable analyses confirmed age as a significant determinant and various vaccination schedules showed consistent reductions in mortality and ICU admissions. Conclusions: A two-dose initial plus one or more-dose booster BNT162b2 regimen effectively reduced mortality risks and ICU admission.eninfo:eu-repo/semantics/openAccessCOVID-19mortalityintensive care unitvaccineArticle10.18621/eurj.1632009116116711751356946