Multiple sclerosis is a serious, potentially disabling disease of the central nervous system that often affecting several areas of the brain and spinal cord at the same time. A large number of patients with this disease have been identified in Russia. The aetiology of multiple sclerosis is still under investigation. Every year, new data emerge on the influence of different factors and their interaction. Modern science is actively studying the mechanisms of multiple sclerosis progression, the role of mitochondria in inflammation and neurodegeneration, as well as the impact of COVID-19 on the possibility of development and progression of multiple sclerosis. In this review, we will consider the impact of the SARS-CoV-2 virus on the course of multiple sclerosis.