COVID-19 and multiple sclerosis: is there a connection?

Multiple sclerosis (MS) is a chronic immune-mediated disease of the central nervous system, which is based on inflammatory demyelination and neurodegeneration. Over the course of the COVID-19 pandemic, there has been a perception that the virus has an effect on the course of immune processes. The questions of whether the frequency of autoimmune diseases, including the nervous system, and their course has changed have been discussed. Aim of the study was to assess the clinical and epidemiological characteristics of MS during the COVID-19 pandemic from 01.01.2020 to 01.01.2023 in Novosibirsk. In the course of our work, we studied the incidence of MS and the features of the clinical picture of the debut of MS associated with COVID-19 infection. Material and methods. The study included 628 patients with MS living in Novosibirsk with the onset of the disease in the period before the pandemic from 01.01.2017 to 12/31/2019 (341 patients) and during the pandemic from 01.01.2020 to 01.1.2023 (287 patients). Results. The incidence rates of MS in Novosibirsk were calculated, it was 7.1 7.6 6.4 7.38 6.92 and 3.2 per 100 thousand population in 2017, 2018, 2019, 2020, 2021 and 2020, respectively. The average incidence of MS in the study period before the pandemic was 7.03 per 100 thousand population, during the pandemic – 5.83 per 100 thousand population (critical value of the Student’s t-test = 1.972, with a significance level of a = 0.05). When analyzing the association of clinical manifestations of the onset of MS with COVID-19, it was found that coordination disorders were observed in patients with moderate infection more often than in patients with mild infection (p < 0.05; odds ratio 0.410, 95% confidence interval 0.162–1.035). No statistically significant correlation of clinical manifestations with the severity of infection was shown for patients with primary progressive MS, however, the predominance of the multi-focal nature of disease after a more severe course of COVID-19 was noted (40 %). After the first clinical demyelinating episode in the group of patients with relapsing-remitting MS, the chances of complete recovery in patients with mild infection are 2.8 times higher than in patients with moderate infection (p < 0.05). Conclusions. Thus, as a result of the conducted study, the effect of COVID-19 on the change in the incidence of MS was not revealed. In the process of analyzing the clinical features of MS during the pandemic, it was found that COVID-19 infection can contribute to an unfavorable course of MS with worse recovery of neurological deficits after episodes of exacerbations, which leads to the accumulation of disability of patients.