Background:   As the world experiences successive waves of corona virus disease (COVID-19) pandemic, global efforts to develop and distribute an effective vaccine produced several promising options. The aim of our study was to assess the difference in pulmonary involvement between vaccinated and unvaccinated patients among Egyptians. Patients and methods:   Our study involved 234 patients who were tested positive for COVID-19 and had classic symptoms. They were split into 2 groups: group 1 (131 unvaccinated patients), and group 2 (103 fully vaccinated patients). Patients underwent high resolution computed tomography (HRCT) of the chest. All scans were evaluated, and CT severity score (CT-SS) was calculated. Results: For group 1 the patients' ages ranged from 19 to 84, mean = 44.5 years (+ 16.2 SD), 76 (58%) males and 55 (42%) females, while group 2 age ranged from 18 to 85, mean (+SD)=  42.2 years (+ 16.6 ), 59 (57.3%) males and 44 (42.7%) females". The presence of ground glass opacities and white lung sign varied significantly between both groups (P=0.001 and 0.002 respectively). For other recorded signs no significant difference was detected. The mean computed tomography severity score (CT-SS) for group 1 was 11.25 (± 6.6 SD). While for group 2 it was 6.32 (± 4.33 SD). The difference between studied groups was highly significant (P<0.001). Conclusion: Our results showed that COVID vaccine could effectively reduce the extent and severity of lung involvement in vaccinated patients compared with unvaccinated patients. Further wide-ranging clinical studies are needed to support our results.