mRNA COVID-19 vaccines do not increase the short-term risk of clinical relapses in multiple sclerosis.

Multiple sclerosis (MS) is a chronic, immune-mediated disorder of the central nervous system. A novel coronavirus, namely SARS-CoV-2, has been recently responsible for the highly infectious disease referred as COVID-19, rapidly spreading all over the world. Many vaccines have been developed to control COVID-19 pandemic, including the mRNA vaccines Pfizer/BioNTech (BNT162b2) and Moderna (mRNA1273).1 The vaccination of people with MS (pwMS) has been recommended by several national and international MS societies. However, effectiveness and safety of anti-COVID-19 mRNA vaccines in MS need to be confirmed. The aim of this study was to evaluate the short-term risk of clinical relapses in pwMS in the 2 months after the first administration of an mRNA COVID-19 vaccine. Twenty-five Italian MS tertiary centres participated to this prospective, self-controlled, multicentric observational study. In Italy, COVID-19 population vaccination started at the end of December 2020 and first involved healthcare professionals. All pwMS, diagnosed according to McDonald’s 2017 criteria, who underwent the first dose of an mRNA COVID-19 vaccine within January 2021 were recruited from each participating centre. All patients received Pfizer/BioNTech BNT162b2 vaccine according to vaccine availability in Italy. Database lock was planned on 31 March so that all patients were followed for at least 2 months after the first dose. The following data were collected: (1) sex; (2) age and disease duration; (3) disease course (relapsing remitting; secondary progressive; primary progressive); (4) disability score (Expanded Disability Status Scale, EDSS); (5) clinical relapses in the year before vaccination, with specific regard to the 2  months immediately preceding vaccination; (6) MRI activity in the year before vaccination (new T2 or Gd enhancing—Gd+—lesions); (7) previous molecular swab confirmed SARS-CoV-2 infection; (8) vaccine administration date and (9) disease-modifying treatments at the time of vaccination. The presence, characteristics and number of relapses in the 60 days after the first administration of …