Abstract Background The first cases of COVID-19 began in Wuhan, Hubei Province china, in December 2019. Since then, this disease caused by a highly pathogenic virus, severe acute respiratory syndrome coronavirus (SARS-COV-2), has been labelled as a global pandemic. It is believed that the primary means of viral spread is via respiratory droplets during close-range, human-to-human contact. Aim of the Work To assess immunogenicity and to compare adverse effect following COVID-19 vaccinations in patients with systemic inflammatory autoimmune diseases vs matched healthy controls. Patients and Methods This is a cross sectional study. Two groups of subjects were enrolled in the study after consideration of both inclusion and exclusion criteria. Group A: patients with systemic inflammatory auto immune disease (60 subjects) including (30 patients with systemic lupus erythematosus, 30 patients with rheumatoid arthritis) who received two doses of COVID-19 vaccine. Group B: age-matched healthy controls who received two doses of COVID-19 vaccine (30 Subjects). All patients were recruited from the outpatient clinic of department of Internal Medicine – Rheumatology division at Ain Shams University Hospital. Control group were recruited from medical and non-medical staff working at Ain Shams University Hospital. Results There was no statistically significant difference in the titre of anti-spikes antibodies with the use of different immune suppressive drugs in RA group such as methotrexate and leflunomide with p-value =0.935,0.257, respectively,also in SLE patients there was no statistically significant difference in the titre of anti-spikes antibodies with the use of different immune suppressive drugs in SLE group such as azathioprine, mycophenolate mofetil and cyclophosphamide with p-value = 0.317, 1.000 and 0.513 respectively,(all patients in our study were on corticosteroids and hydroxychloroquine). There was statistically significant difference as regarding disease activity in RA patients before and after covid-19 vaccine with p-value = 0.001,with a total percentage of 26.70% of patients developed mild disease activity,13.30% developed moderate disease activity while 3.3% of patients developed severe activity and as regarding SLE patients there was statistically significant difference as regarding disease activity in SLE patients before and after covid-19 vaccine with p-value = 0.002,with a total percentage of 23.3% of patients developed mild disease activity,6.7% developed moderate disease activity while 10% of patients developed severe activity. Conclusion Comparable side effects in both control and patients group with only minor side effects were reported. The Sinopharm BIBP COVID-19 vaccine was immunogenic in the majority of patients in comparison to control group, with an acceptable safety profile. The use of different immune suppressive therapies (methotrexate, azathioprine, mycophenolate mofetil,cyclophosphamide) didn’t affect humoral response after two doses of the vaccine. Apparent impact on disease activity of both SLE and RA patients but mainly in the form of mild disease activity.