PhD Scientific Days 2026

Poster Session 3.L - Health Sciences

Vaccination Reduces Severe Outcomes in High-Risk COVID-19 Patients: A Fourth-Wave Retrospective Cohort Study

Name of the presenter

Köves-Dobszai, Dalma

Institute/workplace of the presenter

Centre for Translational Medicine

Authors

Dalma Dobszai¹, Zsanett Macht-Szalai², Péter Hegyi¹, Andrea Szentesi¹
1: Centre for Translational Medicine, Semmelweis University, Budapest, Hungary
2: Institute for Translational Medicine, Medical School, University of Pécs, Pécs, Hungary

Text of the abstract

Introduction
COVID-19 caused substantial global morbidity and mortality. Comorbidities, particularly metabolic conditions, significantly increase the risk of severe disease. However, data on the effectiveness of vaccination in high-risk populations during later pandemic waves remain limited, especially in Central and Eastern European populations.
Aims
To evaluate the impact of COVID-19 vaccination on mortality and ICU admission, with a focus on patients with comorbidities.
Methods
We conducted a retrospective cohort study including 1,029 adult COVID-19 patients treated at the University of Pécs during the fourth wave (Jan 2021–Feb 2022). Patients were stratified by vaccination status and comorbidities. Primary outcomes were in-hospital mortality and ICU admission.
Results
Among patients, 450 (43.7%) were vaccinated and 579 (56.3%) were unvaccinated. Mortality was comparable in vaccinated and unvaccinated patients (28% vs. 30%, respectively; OR=0.90, p=0.44), while ICU admission was significantly reduced (23% vs. 32%; OR=0.63, p=0.001). Mortality was similar across dose groups (27-28%). Vaccination was associated with lower mortality in diabetes (31% vs. 42%; OR 0.61, p=0.04), in hypertension (32% vs. 36%; OR=0.82, p=0.22), and in obesity (29% vs. 34%; OR 0.78, p=0.25). In patients with combined metabolic comorbidities, defined as the coexistence of obesity, diabetes, and hypertension, mortality remained high but was substantially lower in vaccinated patients (32% vs. 45%; OR=0.57, p=0.07). Lower mortality was also observed in respiratory (19% vs. 37%), cardiovascular (33% vs. 40%), autoimmune (34% vs. 38%), and oncologic diseases (31% vs. 40%).
Conclusion
Vaccination was associated with reduced ICU admission and lower mortality, particularly in high-risk patients with multiple metabolic comorbidities, supporting its importance in vulnerable populations. Further multivariable analyses are needed.
Funding
Funding was provided by the National Research, Development and Innovation Fund to Dalma Dobszai (EKÖP-2025-358).