Abstract
Background and Objectives: The COVID-19 pandemic has had a significant impact on global health, with serious outcomes, such as lung damage, being major determinants of patient morbidity and mortality. Immunization has been essential in attenuating these outcomes. This study aimed to evaluate the impact of COVID-19 vaccination on disease severity, particularly focusing on pulmonary involvement, among hospitalized patients. Materials and Methods: A retrospective cohort study was conducted at Victor Babes Hospital, Timisoara, involving 3005 patients diagnosed with COVID-19 between December 2020 and March 2022. Patients were stratified into vaccinated and unvaccinated groups. Results: The study found that vaccinated patients had significantly lower rates of severe pulmonary involvement compared to unvaccinated patients. Specifically, only 24.24% of vaccinated patients experienced severe lung involvement, compared to 35.64% in the unvaccinated group (p < 0.001). Vaccinated individuals had shorter hospital stays (8.96 ± 6.40 days vs. 10.70 ± 6.29 days), but this difference was not statistically significant (p = 0.219). Additionally, chronic pulmonary diseases and stroke were less prevalent among vaccinated patients, highlighting the protective effect of vaccination. Conclusions: COVID-19 vaccination significantly reduces the severity of disease, particularly in preventing severe pulmonary involvement, which is a major determinant of patient outcomes. These findings underscore the importance of ongoing vaccination efforts and the need for booster doses to maintain immunity, especially as new variants emerge. The study supports the continued prioritization of vaccination in public health strategies to mitigate the long-term impact of COVID-19.