The CT Scan Lung Severity Score and Vaccination Status in COVID-19 patients in India: Perspective of an Independent Radiology Practice

Background The COVID-19 patients often undergo a high-resolution CT scan to determine extent of their lung involvement. The aim of this study was to determine lung involvement in confirmed/suspected COVID-19 patients (encountered at an independent radiology practice) and its correlation to vaccination status amidst the second COVID-19 wave in India. Methods We retrospectively queried our data since April 2021 to identify adult patients (>17 years) who had confirmed (positive RT-PCR or antigen test) or suspected COVID-19 (classic symptoms but negative RT-PCR) and received a high-resolution CT scan to determine the extent of their lung involvement using the CT severity (CT-SS) score. Patients were classified in 3 groups based on their vaccination status to determine its correlation with the CT-SS score: fully vaccinated, partially vaccinated, and unvaccinated. Basic descriptive statistics, univariate tests and multivariate linear regression analysis were used. Results We identified 229 patients (median age 45 years, 60% male) of which 205 (89%) had confirmed COVID-19 (positive RT-PCR) and 24 had suspected disease (negative RT-PCT but classic symptoms). Of the 229 patients 29 (13%) had complete vaccination, 38 (17%) had partial vaccination and 162 (70%) had no vaccination. The CT score of the completely vaccinated patients was significantly lower compared to partially or unvaccinated patients (median 0 v. 3.5 v. 10, respectively p<.01). A multivariate linear regression model showed that partial or fully vaccinated patients had lower CT severity score compared to unvaccinated patients (adjusted R squared = 0.47). Conclusion We present here the real-world findings from an independent radiology practice (a unique and common practice model), in India amid the second COVID-19 wave showing significantly lower CT severity score in fully or partially vaccinated patients compared to unvaccinated patients. Complete vaccination in patients could be critical in preventing severe lung disease.