Incidence of multiple sclerosis relapses and pseudo-relapses following COVID-19 vaccination

The coronavirus disease 2019 (COVID-19) pandemic created an urgency for an effective vaccine. The FDA approved vaccines offered by Pfizer-BioNTech (BNT162b2), ModernaTX (mRNA-1273) and Janssen/Johnson & Johnson (Ad26.COV2.S) have shown minimal side effects (SE) in general population studies. Multiple sclerosis (MS) patients were not specifically represented in the above studies. The MS community is interested in how these vaccines behave in people with MS. In this study, we compare the SE experienced by MS to that of the general population after SARS-CoV-2 vaccination and evaluate their risk of relapses or pseudo-relapses.

A retrospective, single-site, cohort study of 250 MS patients who received the initial cycle of FDA approved SARS-CoV-2 vaccines with 151 of whom also received an additional booster dose. SE resulting immediately after COVID-19 vaccination were collected as part of the standard clinical care during patient visits.

Out of the studied 250 MS patients, 135 received the first and second doses of BNT162b2 with less than 1% and 4% pseudo-relapses respectively and 79 received the third BNT162b2 dose with a pseudo-relapse rate of 3%. 88 received the mRNA-1273 vaccine with a pseudo-relapse frequency of 2% and 5% after the first and second doses respectively. 70 patients had the mRNA-1273 vaccine booster with a 3% pseudo-relapse rate. 27 received the Ad26.COV2.S first dose, 2 of whom received a second Ad26.COV2.S booster dose, with no reports of MS worsening. No acute relapses were reported in our patient population. All patients experiencing pseudo-relapse symptoms returned to baseline within 96 h.

COVID-19 vaccine is safe in patients with MS. Cases of temporary worsening of MS symptoms following SARS-CoV-2 are rare. Our findings support those reported by other recent studies and the CDC recommendation for MS patients to receive the FDA-approved COVID-19 vaccines, including the boosters.