MS patients treated with anti-CD20 therapies ocrelizumab and rituximab have an increased risk of severe COVID-19 infection, whereas treatment with interferon or teriflunomide could reduce that risk. These were the preliminary outcomes of a retrospective, multi-center observational study in a cohort of Italian MS patients investigating the impact of disease-modifying treatments on COVID-19 course of disease.


Italian MS patients registered on the Multiple Sclerosis and COVID-19 (MuSC-19) platform with confirmed COVID-19 infection (n=1,538) were selected for this study [1]. The influence of disease-modifying therapies on COVID-19 severity was examined through logistic regression analysis. Infection severity was defined on a 4-level nominal scale: asymptomatic; symptomatic without signs of pneumonia; radiological defined pneumonia or hospitalization; intensive care unit (ICU) or death. Dr Maria Pia Sormani (University of Genoa, Italy) presented the results, which demonstrated an association between the use of anti-CD20 therapies (ocrelizumab or rituximab) and an increased risk of severe infection (OR 1.89). In contrast, a protective effect against severe COVID-19 was observed for interferon (OR 0.36) and teriflunomide (OR 0.49, trending). Additional analysis revealed that duration of anti-CD20 treatment possibly increases the risk of severe infection (≤6 months: OR 1.56; >2 years: OR 2.75). Other factors that had a significant effect on infection severity in this cohort were age (older), sex (male), EDSS scores, presence of comorbidities, and high-dose steroid use one month before symptoms.


  1. Sormani MP, et al. Different disease modifying therapies can increase or decrease Covid-19 severity in Multiple Sclerosis. S28.002, AAN 2021 Virtual Congress, 17-22 April.