Association between Chest CT Severity Scores and SARS-CoV-2 Vaccination among COVID-19 patients: A Cross-sectional Study from Pune, India

Abstract

Introduction: The novel Coronavirus disease-2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is seen to primarily affect the human respiratory system. Chest CT Severity Score (CTSS) provides a semi quantitative assessment of pulmonary involvement in COVID19 patients. COVID-19 pandemic mitigation measures such as SARS-CoV-2 vaccination are being deployed worldwide. However, with the emerging variants of concern of SARS-CoV-2, a high prevalence of post vaccination breakthrough infections is seen. Aim: To assess the association of CTSS with the vaccination status in a cohort of COVID-19 patients referred to a tertiary diagnostic centre and to evaluate the association of CTSS with other clinical parameters including co-morbidities in these patients. Materials and Methods: This cross-sectional observational study was conducted at a tertiary care diagnostic imaging centre in the city of Pune, Maharashtra, India. Data of 1002 symptomatic, adult patients who underwent chest CT and SARSCoV-2 Reverse Transcription Polymerase Chain Reaction (RTPCR)/Rapid Antigen Test (RAT) laboratory test between March 13, 2021 and June 22, 2021, were collected. COVID-19 reporting and Data System (CO-RADS) categories and the corresponding semi quantitative CTSS were calculated for each patient. Based on their vaccination status, patients were categorised into three groups: unvaccinated, partially vaccinated and fully vaccinated. The association of CTSS with various categories of vaccination status, demographics, co-morbidities and stages of the disease of the patients, was evaluated. Results: Of the 1002 COVID-19 patients, 768 (76.6%) were unvaccinated, 190 (19.0%) were partially vaccinated and 44 (4.4%) were fully vaccinated. Mean CTSS in the fully vaccinated cohort was significantly lower (3.75±4.7) than that in the partially vaccinated (6.05±5.7) and unvaccinated (8.29±4.9) patients (mean 3.75 vs. 6.05 vs. 8.29, respectively; (p<0.05). Mean CTSS in patients with no co-morbidities was significantly lower than that in patients with hypertension and diabetes (7.12 vs. 8.75 vs. 10.39, respectively; (p<0.05). Conclusion: Significant association was noted between the Chest CTSS and the vaccination status, age, gender, co-morbidities and stage of disease in this large cohort of COVID-19 patients. The study reiterates that full vaccination aids in reducing the severity of lung involvement in COVID-19 infection.