 My name is Dr. Vashakha. I am a resident in the Department of Radio Diagnosis D.Y. Partel Medical College, Navi, Mumbai, Maharashtra. So I have done a retrospective study to correlate the HRCT changes in RT-PCR positive patients and their vaccination status. The first case of the notorious ongoing SARS-CoV-2 aka COVID-19 nemonitis was confirmed on 6 January 2019. Clinically, the patient can present with symptoms like fever, chills, cough, shortness of breath, difficulty in breathing, an osmia, body ache and few severe presentation like ARDS. Radiologically, typical pulmonary changes can be seen on HRCT chest study. RT-PCR is the gold standard lab investigation for confirmation. Vaccination has led to a reduction in the transmission of the viral infection with decrease in the severity of infection in affected individuals. Two vaccines have been approved in India at the time of the study that is Co-Vaccine and Co-Visield, both of which require two doses for complete vaccination. The aim of this study is to determine lung changes with respect to their vaccination status, whether the patient is partially vaccinated or completely vaccinated. Retrospectively, data was collected between 1st June to 18th August 2021. HRCD chest of patients with RT-PCR positive status that is Co-RADS-6 and Co-RADS-5 with RT-PCR positive status confirmed on follow were included in the study. The type of vaccine along with the dose of vaccine was recorded. Patients above the age of 18 years who are eligible for vaccination in India at the time of study were considered. CT severity score was also documented. So the results of my study showed that out of 240 patients with RT-PCR positive status and COVID suspects were that 56.25% were males and 43.75% for females. Out of the total, 79.58% were non-vaccinated, 13.75% were partially vaccinated and only a small percentage that was 6.67% were fully vaccinated. The main chest CT severity score in non-vaccinated patients came out to be 12.199 out of 25. In partially vaccinated, it was 10.575 out of 25 and in fully vaccinated, it was 7.5. The main CT severity score was lower for patients who had received both doses of vaccination than those who had received only first dose of vaccine. Main CT severity score in patients after first dose of vaccine came out to be 10.5 and after both doses was 7.5. HRCT changes were noted in 34 patients who had received the first dose of vaccine. Of these six patients had received Covaxin and 28 had received Covish shield as their first dose. 16 patients showed changes on HRCT after being fully vaccinated that is having taken two doses of the same vaccine. Out of these five had received Covaxin and 11 had taken Covish shield. The main CT severity score after the first and second dose of Covaxin was 10 and 11 respectively. And the main CT severity score after first and second dose of Covish shield was 11 and 5.9 respectively. So coming on to the discussion, pulmonary changes noted on HRCT include variable presentation, which include GGOs, areas of consolidation, crazy pavement pattern and fibrous bands. CT severity score is done by calculating the percentages of each of the five lobes that are involved. The total CT severity score can range from 0 that is no involvement to 25 maximum involvement. We observed that patients with complete and partial vaccination had a lower average CT severity score, which supports the effectiveness of the vaccine in preventing the severe disease to an extent. Significant difference in the mean CTSS was noted between that of non-vaccinated and fully vaccinated patients. However, no significant difference or correlation was noted between the mean CTSS of non-vaccinated and partially vaccinated and fully vaccinated patients. The group which had received the first dose of Covish shield vaccine had a marginally lower CTSS that was 10.6 on 25 as compared to the group which had received Covaxin as the first dose that was 10 on 25. The average CTSS was significantly lower for the group which had received second dose of Covish shield vaccination that was 5.9 on 25 in comparison to those who had received second dose of Covaxin which was 11 on 25 hence showing that the second dose of Covish shield is more effective than second dose of Covaxin. Also taking two doses of Covish shield is more effective than two doses of Covaxin. In conclusion, lower average CT severity score is in fully or partially vaccinated patients is seen as compared to unvaccinated patients. Complete vaccination in patients could be critical in preventing severe lung disease. Here is a 28 year old male who has already received the first dose of Covaxin and shows GGOs on HRCT. His corads was 6 and CTSS was 12. 47 year old male with GGOs and consolidation, corads was 6 and CTSS was 15. This was despite having received two doses of Covaxin. 65 year old female already received first dose of Covish shield and her corads was 6 and CTSS was 18. 73 year old male already received two doses of Covish shield, corads was 6 and CTSS was 30 and in spite of that it showed GGOs.