The risk of COVID-19 severity in patients with ms appears to be associated with immunotherapy

Immunomodulatory drugs are important to control disease activity in relapsing-remitting multiple sclerosis (MS). Anti-CD 20-therapy is one of such medications. In Sweden, extensive off label prescription of rituximab (RTX) in MS has been documented; it is presently prescribed for more than half of all treated MS patients. The rationale for the increasing prescription of RTX was previous data from phase II and observational studies supporting high efficacy and safety, in addition to the financial aspect. We report national data on usage of disease modifying therapies in MS patients and risk of severe COVID-19 in association with RTX exposure within this group. The Swedish National MS Registry (SMSreg) aims to cover all patients with MS in the country, (n=approximately 18,000). After COVID-19 pandemic started in Sweden, a new section was established in it to register clinical and demographic parameters in COVID-19-infected patients. Data presented in the current report were obtained from the SMSreg. A total of 85 out of approximately 6,000 RTX-treated Swedish MS patients had been hospitalized with COVID-19 (as reported from the SMSreg, June 16, 2021) and adjusted analyses showed a 2-3 fold increase in a risk (OR = 2.89; p = 0.001) of hospitalization for anti-CD20 treated patients. A change of praxis was introduced in Sweden in spring 2020, resulting in a majority of patients receiving RTX infusions with extended intervals in order to reduce the risk of severe COVID-19 infection. Current Swedish registry data suggest that exposure to RTX in MS may affect the clinical outcome of COVID-19 infection. These observations have rapidly impacted use of immunomodulatory drugs in Swedish MS patients.