Abstract
BACKGROUND AND AIMS: The COVID-19 pandemic was a special situation for patients treated with disease-modifying therapies (DMTs). Infections may provoke disease activity and determine the choice of DMTs. Moreover, DMTs create a potentially increased risk of infections. The study aimed to assess the impact of the COVID-19 pandemic and the importance of COVID-19 vaccination on the course of multiple sclerosis (MS). METHODS: The 8-year single-center retrospective cohort study compared treatment changes and infection incidence in 115 MS patients before and during the COVID-19 pandemic, as well as COVID-19 incidence and severity before and after COVID-19 vaccination. A multivariate approach assessed the effects of specific factors (age, sex, disease duration, prognostic profile, disease activity before the pandemic, DMTs, and infections) on the course of MS. RESULTS: Relapse activity was the most common reason for therapy change, with no significant differences (56.52% vs. 61.52%, p = 0.998) before and during the pandemic. There were no differences in the rate of infections before and during the pandemic (67.82% vs. 55.65%, p = 0.16). The severity of COVID-19 courses showed a significant improvement after vaccination (p = 0.047). In the multivariable approach, the only significant factor associated with a higher risk of relapse was disease activity before the pandemic period (OR = 6.80, p = 0.010). CONCLUSIONS: The COVID-19 pandemic did not affect the course of MS in long-term follow-up. The only factor associated with relapse activity during the pandemic period was disease activity in the pre-pandemic period. COVID-19 vaccination may be an essential tool in the care of MS patients.