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The effects of COVID-19 vaccination on people with multiple sclerosis has not been studied in sufficient detail. This study provides an analysis of the available data.

COVID-19 infection as well as the various COVID-19 vaccines have caused health complications for some patients with certain medical conditions. Despite the vaccine being available for a number of years, data are still sparse regarding the safety of COVID-19 vaccines in patients with multiple sclerosis (MS). Although the mechanisms involved in neuroimmunological reactions to the COVID-19 vaccines are not currently well understood, it is hypothesized that vaccine-induced over-activation of the immune system, including humoral and cell-mediated immune responses, is partially responsible. 

Centralized COVID-19 Vaccination Data From Patients With MS Is Scarce

Patients with MS have not been included in seminal randomized controlled trials for the regulatory approval of currently licensed vaccines, in part leading to the lack of data regarding their responses. This study, published in the Multiple Sclerosis Journal, estimates the proportion of MS patients who experienced relapse among total vaccine recipients, as well as the rate of transient neurological worsening, adverse events, and previous outcomes of interest for other vaccine types.

Data from 19 studies comprising a total of 14,755 patients with MS and a total of 23,088 COVID-19 vaccine doses were included in this analysis. The mean age was 43.3 years. The authors evaluated publication bias using funnel plots for each analysis outcome. The pooled proportion of patients with MS who experienced relapse at a mean time interval of 20 days from vaccination was 1.9%, with a relapse risk independent of the type of vaccine. Transient neurological worsening was found in 4.8% of patients, and adverse events and serious adverse events were found in 52.8% and 0.1% of vaccinations, respectively. 

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Adverse Effects Are Common, but Generally Very Mild

Although adverse effects were recorded in about half of the total vaccinations, these tended to be mild side effects including pain at the injection site, malaise, fever, and fatigue. The transient neurological worsening after the second dose is in accordance with evidence that points to an increased reactogenicity after the second dose of MRNA vaccines is transmitted.

Although post-vaccination relapses are rare, the risk of transient neurological worsening is large enough to warrant increased caution and monitoring of this group. Weighted against the risk of COVID-related complications among patients with MS, these findings still indicate that vaccination is the best route for most MS patients.


Stefanou, M. I., Palaiodimou, L., Theodorou, A., Christodoulou, M. V., Tzartos, J. S., Tzanetakos, D., Kitsos, D., Chondrogianni, M., Zouvelou, V., Dardiotis, E., Tzavellas, E., Syrigou, E., Benetou, V., Paraskevas, G. P., Tsiodras, S., Tsivgoulis, G., & Giannopoulos, S. (2023). Safety of COVID-19 vaccines in multiple sclerosis: A systematic review and meta-analysis. Mult Scler, 13524585221150881. https://doi.org/10.1177/13524585221150881