Background: The COVID-19 vaccination was one of the most important medical events of the century which resulted in the end of a horrible pandemic. Since NMOSD patients were high-risk for COVID-19 infection, they had priority in vaccination like patients with other autoimmune disorders. But the point is that immunological effects of vaccines may lead to disease activation and acute relapses.
Objectives: In this study we aimed to report any acute relapses or neurological deficits, that occurred within three months after each episode of COVID-19 vaccination in Iranian NMOSD patients. The type and severity of symptoms were noticed.
Methods: We asked 170 NMOSD patients who had been registered in our NMOSD clinic electronic database about experiencing acute relapses or neurological deficits during three months after each dose of COVID-19 vaccine. There was positive response in 7 patients out of 170. The duration between vaccine shot and neurological sign had been considered.
Results: Acute relapses occurred in seven NMO patients (four seropositive) after vaccination shot. All of them were female with mean age of 39.28±7.02 years and disease duration about 7.14±2.41 years. The earliest relapse happened 2 weeks after vaccine shot and the latest one happened two months later but most of the relapses occurred about one month after vaccination. The type of neurological conflict included optic neuritis in two patients, myelitis in two patients, cranial nerves palsy, area postreoma syndrome and paresthesia. They received corticostroid pulse therapy. Optic neuritis in one patient was so severe that she received plasma exchange therapy. All of them were treated by rituximab as maintenance therapy.
Conclusion: In our study 4.11% of patients experienced acute relapses after vaccination but we don’t know if it is a coincidence, or it is directly due to the immunological effect of vaccine. The other probability is the duration between receiving rituximab and vaccination, which is usually more than 4 months and in this time the drug effect is reduced and the immune system is more prone to be activated by vaccination.