The Effect of Covid-19 on the Disease Course of Multiple Sclerosis

Methods The Nationaal Multiple Sclerose Centrum (NMSC) Melsbroek is a large highly-specialized center specifically focusing on neurological management, multidisciplinary care and rehabilitation in patients with MS. Since March 2020 (i.e., the onset of the pandemic in Belgium, and the first of five waves of spiking infection numbers thus far in our country), clinical data of patients followed at the center have been collected in a local database in case of COVID-19 diagnosis. The following items have been recorded: name, gender and date of COVID-19 diagnosis; age, Expanded Disability Status Scale score, MS duration, clinical subtype and DMT regimen at time of COVID-19 diagnosis; COVID-19 severity (method 1: categorized as ambulatory, hospitalized, death; method 2: categorized as asymptomatic, mild illness, moderate illness, severe illness, critical illness and death); vaccination status (categorized as non-vaccinated, fully vaccinated, fully vaccinated + booster) at time of COVID-19 diagnosis. On February 28, 2022, this database was locked and consisted of 234180 unique individual COVID-19 cases.

The NMSC Melsbroek features a second and more large database containing a broad variety of (para)clinical information gathered during routine follow-up, which includes regular testing of general disability with the EDSS, leg function/ambulation with the Timed 25-Foot Walk Test (T25FWT), hand function/dexterity using the 9-Hole Peg Test (9HPT) and cognition/information processing speed with the Symbol Digit Modalities Test (SDMT). For each of these parameters, the first two assessments before COVID-19 diagnosis (labelled T0 and T1, respectively; T1 is the closest to COVID-19 diagnosis), and the first thereafter (labelled T2), were retrieved for each COVID-19 subject. If clinical measurements were performed during an in-house stay for rehabilitation purposes, only those performed on admission were retained (thus not necessarily those the closest to the COVID-19 infection).