mRNA COVID-19 vaccines do not increase the short-term risk of clinical relapses in multiple sclerosis.Di Filippo M, Cordioli C, Malucchi S, Annovazzi P, Cavalla P, Torri Clerici V, Ragonese P, Nociti V, Radaelli M, Laroni A, Buttari F, Lorefice L, Ferraro D, Gajofatto A, Prosperini L, Fantozzi R, Boffa L, Lanzillo R, Moccia M, Clerico M, De Luca G, Tomassini V, Calabrese M, Borrelli A, Paolicelli D, Maniscalco GT, Gazzola P, Gallo A, Solaro C, Cocco E, Gasperini C, Tortorella C; RIREMS (Rising Researchers in MS) group.J Neurol Neurosurg Psychiatry. 2021 Aug 18:jnnp-2021-327200. doi: 10.1136/jnnp-2021-327200. Online ahead of print.
Our preliminary analysis demonstrated that the Pfizer/BioNTech BNT162b2 vaccine does not increase the short-term risk of clinical reactivation in pwMS. Recently, Achiron et al reported in an observational study on 555 pwMS a similar rate of patients with acute relapse after Pfizer/BioNTech BNT162b2 vaccine. No increased risk of relapse activity was estimated comparing that cohort with a cohort of non-vaccinated patients evaluated in the same period in the prepandemic era.5 The latter study, however, suffers of the limitation of an heterogeneous follow-up period (about 20% of patients with relapses were followed for less than 14 days after immunisation) which might have lowered the number of recorded relapses. Our study is the first prospective study including a large cohort of patients with MS who were followed, with a self-controlled design, for at least 2 months after the first dose of the Pfizer/BioNTech BNT162b2 vaccine. A limit of our study, mainly related to its real life context, is the lack of MRI data, which might prevent the detection of potential MRI activity in absence of clinical relapses, as well as the short-term follow-up. Larger observational studies with longer follow-up would be desirable. Moreover, due to the low number of patients with progressive MS in the cohort (21 out of 324 subjects, 6.5%), no clear conclusions can be drawn on the effects of Pfizer/BioNTech BNT162b2 vaccination on disease worsening in progressive MS. Despite these limitations, we think that the results of our study can improve clinical practice driving clinical decisions and support the recommendation to promote access of pwMS to COVID-19 vaccination.