A Study to Assess the Potential Impact of Disease Modifying Therapies on COVID-19 Outcomes and the Antibody Response Following an Infection With SARS-CoV-2 in Patients With Multiple Sclerosis Within the Swiss Multiple Sclerosis Cohort.

This nested project of the Swiss Multiple Sclerosis Cohort (SMSC) is to assess the severity of COVID-19 and the magnitude of antibody response after infection with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in patients already treated or not with various immunotherapies for multiple sclerosis followed in the framework of the SMSC.

To assess the frequency and severity of SARS-CoV-2 infections and associated symptoms in the study population, data is collected from systematic questioning during the SMSC-visits and from serum samples collected every 6-12 months within the SMSC (for measurement of anti-SARS-CoV-2 antibodies in pre-pandemic reference samples and prospectively to determine the anti-SARS-CoV-2-serostatus during the study period).

Combining the information on anti-SARS- CoV-2 serostatus and infection history opens the opportunity to determine the number of patients without or with only mild vs. moderate to severe COVID-19 symptoms in large groups of patients with Multiple Sclerosis (MS) treated with immunotherapies targeting various components of the immune system.