Multiple sclerosis in the era of COVID-19: disease course, DMTs and SARS-CoV2 vaccinations

As of January 21st 2022, over 340 million are confirmed cases of coronavirus disease 2019 (COVID-19), including nearly 5.6 million deaths. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is neurotropic and affects the neural parenchyma through direct viral invasion from the nasal mucosa and postinfectious cytokine storm. Further challenges of SARS-CoV-2 infection are nowadays linked to variants of concern. Multiple sclerosis is an inflammatory and progressive degenerative disorder of the central nervous system commonly affecting young adults and potentially generating irreversible disability. Since the beginning of the SARS-CoV-2 pandemic, people with multiple sclerosis (pwMS) have been considered 'extra' vulnerable because of the immune-mediated nature of the disease, the disability status, and the immunomodulatory therapies potentially increasing the risk for viral infection. Today multiple sclerosis neurologists are faced with several challenges in the management of pwMS to both prevent SARS-CoV-2 infection and protection from disease worsening. We aimed to highlight today's most relevant facts about the complex management of pwMS in the COVID-19 era.

The incidence of COVID-19 among pwMS does not differ from the general population. The prognosis of COVID-19 among pwMS is driven by older age, male sex, nonambulatory status, comorbidity as in the general population, as well as by corticosteroid treatment and B-cell depleting agents which decrease seropositivity from SARS-CoV-2 infection and immune responses to SARS-CoV-2 vaccination.

Disease modifying treatments (DMTs) should be regularly continued in relation to SARS-CoV-2 vaccination, but an ad hoc timing is required with B-cell depleting agents. SARS-CoV-2 vaccination is recommended in pwMS with willingness improving through health education programs. Multiple sclerosis does not seem to worsen after SARS-Cov2 vaccination but COVID-19 may enhance disease activity.