Literature Review (Grey)
The COVID-19 pandemic continues to expand across the world. This pandemic has had a significant impact on patients with chronic diseases. Among patients with demyelinating diseases of the central nervous system (CNS), such as multiple sclerosis (MS) or neuromyelitis optica spectrum disorder (NMOSD), concerns remain about the potential impact of COVID-19, given frequent treatment with immunosuppressive or immunomodulatory therapies. In this study, the authors review the existing literature investigating the impact of disease-modifying therapies (DMT) on COVID-19 risk in this group of patients. For this systematic review, they searched PubMed from January 1, 2020, to December 3, 2020. The following keywords were used: “COVID-19” AND “Multiple Sclerosis” OR “Neuromyelitis Optica.” Articles evaluating COVID-19 in patients with demyelinating diseases of CNS were included. This study evaluates the different aspects of the DMTs in these patients during the COVID-19 era. A total of 262 articles were found. After eliminating duplicates and unrelated research papers, a total of 84 articles met the final inclusion criteria in our study. Overall, the experiences of 2493 MS patients and 37 NMOSD patients with COVID-19 were included in this review. Among them, 46 (1.8%) MS patients died (the global death-to-case ratio of COVID-19 was reported about 2.1%). Among DMTs, rituximab had the highest mortality rate (4%). Despite controversies, especially concerning anti-CD20 monoclonal antibody therapies, a relationship between DMT-use and COVID-19 disease course was not found in many studies. This observation reinforces the recommendation of not stopping current DMTs. Other variables such as age, higher Expanded Disability Status Scale (EDSS) scores, cardiac comorbidities, and obesity were independent risk factors for severe COVID-19. Despite the risks of infection, most patients were willing to continue their DMT during the pandemic because of more significant concern about the risk of relapse or worsening MS symptoms. After the infection, immune response attenuation was seen in patients taking fingolimod and anti-CD20 monoclonal antibodies. This may be important for future vaccinations.