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

INTRODUCTION Multiple sclerosis (MS) is a chronic, immunemediated disorder of the central nervous system. A novel coronavirus, namely SARSCoV-2, has been recently responsible for the highly infectious disease referred as COVID19, 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). The vaccination of people with MS (pwMS) has been recommended by several national and international MS societies. However, effectiveness and safety of antiCOVID-19 mRNA vaccines in MS need to be confirmed. The aim of this study was to evaluate the shortterm risk of clinical relapses in pwMS in the 2 months after the first administration of an mRNA COVID-19 vaccine.