Risk of inflammatory reactivation following SARS-CoV-2 vaccine in a large cohort of Multiple Sclerosis patients

ABSTRACT

Background: Whether vaccines play a role triggering or reactivating inflammation in Multiple Sclerosis (MS) has been long debated. There are few reports suggesting that Sars-Cov2 vaccines, as well as COVID-19 infection, may exacerbate relapses in MS. Studies on large cohorts are needed to establish the safety of Sars-Cov2 vaccines in the MS population. Aim(s) To assess the risk of clinical and radiological reactivation following Sars-Cov2 vaccines in patients with MS. Method(s) Patients with MS with known date of SarsCov2 vaccination were identified among those followed up at the Multiple Sclerosis Center of the Tor Vergata University Hospital. Data on clinical relapses and radiological activity (Gadolinium enhancing and new T2 lesions) in the 12 months before and after vaccination were extracted from clinical charts. Result(s) We enrolled 751 patients (64,7% female, mean age 45.9 +/- 11.63 years, 89.9% relapsing-remitting, 5.5% secondary progressive and 4.7% primary progressive, disease duration 11.2 +/- 8.11 years, median EDSS 2.0 [1.0 - 4.0], 12.1% untreated, 41.1% treated with first line immunomodulators and 46.7% with second line high efficacy treatments). Among them, 96.7% received mRNABNT162b2 (Pfizer), 2% mRNA-1273 (Moderna) and 1.3% other COVID-19 vaccines. In the whole cohort we did not find a significant increase of the rate of patients with relapse in the 12 months after vaccines (2.3%) compared to the 12 months before (2,9%, McNemar test, p=0.5), as well as of the rate of patients with radiological activity (both 11.5%, McNemar test, p=0.13). Similar findings were obtained separately analysing untreated patients, patients treated with first line and treated with second line drugs at the time of vaccination. Conclusion(s) Our preliminary results in a large monocentric cohort of MS patients suggest that vaccination with Sars-Cov2 vaccines does not induce disease reactivation. Further analyses are needed to confirm these findings.