Initial comparative analysis of pulmonary involvement on HRCT between vaccinated and non-vaccinated subjects of COVID-19

OBJECTIVES: To compare the high-resolution computed tomography (HRCT)–derived severity score in COVID-19 patients between those who had earlier received the vaccine against the SARS-CoV-2 and those who did not. METHODS: A retrospective cross-sectional analysis of HRCT of the chest was done in correlation with the vaccination status of clinically diagnosed COVID-19 patients. The variable under evaluation was the CT severity score, whereby differential analysis of the variability on this parameter between incompletely (single dose) vaccinated, completely (both doses) vaccinated, and non-vaccinated individuals was the outcome. RESULTS: The analysis included 826 patients of which 581 did not receive any vaccination whereas 196 patients received incomplete (single dose) vaccination and 49 received complete vaccination. Mean CT severity score was lower in completely vaccinated patients (3.5 ± 6.3) vis-à-vis incompletely vaccinated (10.1 ± 10.5) and non-vaccinated (10.1 ± 11.4) individuals. The mean CT score was significantly lower in completely vaccinated patients of lower ages (≤ 60 years) compared to patients above that age. The incidence of severe disease (CT score ≥ 20) was significantly higher in the incompletely vaccinated and non-vaccinated patients compared to that in the completely vaccinated group. CONCLUSIONS: CT severity scores in individuals receiving both doses of SARS-CoV-2 vaccination were less severe in comparison to those receiving a single dose of vaccine or no vaccine at all. KEY POINTS: • Patients who received complete two doses of vaccination had significantly low mean CT scores compared to the partially vaccinated patients and non-vaccinated patients. • The mean CT scores were significantly lower in completely vaccinated patients of lower ages (< 60 years) while patients > 60 years did not show significantly different CT scores between the vaccinated and non-vaccinated groups. • Consolidations and ground-glass opacities were significantly lower in the group receiving complete vaccination as compared to the unvaccinated and incompletely vaccinated patients.