Comparison of Severity of Lung Involvement between Vaccinated and Unvaccinated COVID-19 Patients Assessed using HRCT Scan of Thorax: A Cross-sectional Study

Abstract

Introduction: The Coronavirus Disease-2019 (COVID-19) pandemic, as we all know has wreaked havoc in many countries due to its high rate of infectivity. A High-Resolution Computed Tomography (HRCT) thorax scan is a must to determine the extent of lung involvement, which is helpful in further management. Aim: To compare the severity of lung involvement in COVID- 19 patients with double dose, single dose vaccinated and unvaccinated patients, and thus assess the role of vaccination in limiting the severity of lung involvement in infected patients. Materials and Methods: This was cross-sectional study conducted on 244 patients in the Department of Radiology of Adichunchungiri Institute of Medical Sciences, Bellur, Karnataka, India. The patients were divided into three groups based on their vaccination status. Group A constituted patients who had received two doses of vaccine, group B constituted patients vaccinated with only one dose and group C constituted unvaccinated patients. The Computed Tomography Severity Index (CTSI) score of each patient was assessed. CTSI score of these three groups were compared to know the role of vaccine in preventing or limiting the severity of the disease. The chi-square test, Analysis of Variance (ANOVA) test and t-test were used to compare two means to compare two independent groups. Results: The HRCT scans of a total of 244 patients (166 males and 78 females) were included in the study, analysed and divided into three groups. Group A (n=30) had patients with only mild CTSI score. Group B (n=34) had patients with both mild and moderate CTSI score. Group C (n=180) had patients with mild, moderate and severe CTSI scores. There were no patients with severe lung involvement in group A and group B. The mean CTSI scores in group A, B and C were 0.8, 7.2 and 9.3 respectively (p-value <0.001). Group A and B had less severe lung involvement in comparison to group C. Conclusion: Complete vaccination is essential in preventing severe lung disease due to COVID-19 infection, and to limit complications and long-term sequelae.