Hospital Consequences of COVID-19 Vaccinated and Unvaccinated Patients Among the Iranian Adult Population

Introduction: Coronavirus disease 2019 is an emerging respiratory infectious disease caused by a strain of the coronavirus family. Vaccination is one of the main ways to control this disease. This study was conducted to investigate the severity of pulmonary involvement and some clinical outcomes in vaccinated and unvaccinated COVID-19 patients. Materials and Methods: This retrospective study was conducted between December 2021 and May 2022 with 200 patients in two groups. Sampling was done as available, and patients with COVID-19 admitted to the hospital were examined. Mann-Whitney u and Chi-square test were used for analysis. Results: The average age of the studied patients was 59.2 (±17) years, the most common pattern of lung involvement in this study was the GGO pattern. According to the report in the documents, 45 people in the vaccinated group and nine people in the unvaccinated group did not have any lung involvement in CT and the observed difference was statistically significant (P = 0.001). In terms of oxygen saturation percentage, the lowest level (75%) was observed in the unvaccinated group, also the difference in average hospitalization days between the two groups was statistically significant (P = 0.001).   Conclusion: The results of this study showed that the COVID-19 vaccine can effectively reduce the extent and severity of lung involvement and the need for supplemental oxygen in vaccinated patients. To reduce complications from COVID-19, healthcare workers should continue to promote vaccination at recommended doses for all eligible individuals, as it is effective in controlling serious clinical outcomes.