Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune, rare demyelinating disease of the central nervous system characterized by recurrent attacks which usually involve optic nerves and spinal cord. Although the most common symotoms are myelitis and optic neuritis, it can be presented as cerebral syndromes mainly those related to the brain stem and diencephalon . Since NMOSD is a rare disease and the epidemiological data on this disorder is still insufficient, the establishment of registry and long-term follow up studies are needed to assess the disease course and behavior over a period of time. We stablished an electronic registry system for NMOSD patients in the MS center of Kashani hospital, Isfahan, Iran, since spring 2016. Every patient suspected for NMOSD and documented in our database was included in a follow up study to monitor their disease course and progression. Anti AQP4 antibody and Anti MOG antibody were checked for all patients in a unique lab by cell based assay method. Demographic data and clinical characteristics such as family history, comorbidities,education, number of relapses, presentation signs and radiological findings were recorded. Moreove, relapses, treatment change, triggers, and COVID-19 infection were documented. We investigated the effect of the COVID19 pandemic and vaccination on NMOSD patients. This study included 173 cases with definite diagnosis of NMOSD, and 56 ones were seropositive for AQP4 Ab. 142 were females of which 46 were in the seropositive group. Their mean age was 40.02±11.11 years (45.78±12.88 in AQP4Ab positive group). The mean of age at disease onset was about 30.16±11.90 years. The mean time of follow up was 55.84±18.94 months until today. In 76 patients, there were LETM in the first cervical MRI. 123 patients revealedbabnormality in the first brain MRI. 27 patients had hypothyroidism as the most common comorbidity. 36 cases reported positive family history of multiple sclerosis and also 4 had a family history of NMOSD. The mean age of onset did not differ between seropositive and seronegative group but it was higher than MS patients. Brain MRI showed abnormality in NMOSD patients. Female/male was 4.4/1 which is lower than other studies.