Individuals with multiple sclerosis (MS) face a higher risk of serious COVID-19 infections, leading to worries about potential relapses after vaccination. However, a recent study indicates that those with MS may not experience a greater risk of relapse following COVID-19 vaccination. This research has been published in the August 14, 2024, online edition of Neurology®, the journal of the American Academy of Neurology.
“Individuals with MS are more likely to suffer severe COVID infections due to their degree of physical disability or because of treatments that weaken their immune systems,” explained Dr. Xavier Moisset, one of the study’s authors from Clermont Auvergne University in Clermont-Ferrand, France. “Past studies have indicated that some patients experienced relapses post-vaccination, which may have deterred others from getting their recommended booster shots. Fortunately, our research has shown that there is no significant increase in relapse risk after COVID-19 vaccination for almost all participants.”
However, researchers did identify a slight increase in relapse risk for patients with highly active MS—those who experienced two or more relapses within the past two years—particularly among individuals not undergoing MS treatment.
The study reviewed data from 124,545 people with MS in France. These participants had an average of 14 years living with MS and were monitored for 45 days following their vaccination, as potential vaccine-related relapses typically arise within 28 days after receiving the vaccine.
During the research period, 82% of participants, which is 102,524 individuals, received at least one dose of a COVID-19 vaccine. A total of 95% received a second dose, and 59% were given an additional booster shot.
Participants were administered one or more of the following vaccines: Pfizer BioNTech, Moderna, AstraZeneca, or Janssen.
In the 45-day period post-vaccination, researchers tracked relapses necessitating treatment with high-dose corticosteroids.
After accounting for other factors that could influence relapse rates, including seasonal variation and the impact of disease-modifying treatments, researchers determined that COVID-19 vaccination did not heighten the risk of severe relapses. This conclusion held steady after each vaccine dosage.
To verify these findings, researchers contrasted the situations of those who suffered relapses with those who did not, once again finding no increased risk associated with vaccine exposure. In fact, they noted a slight reduction in relapse risk following vaccination.
“These results are comforting as they suggest that these vaccines can be received without fear of relapse,” stated Moisset. “The lack of such risks is particularly encouraging for individuals with MS, allowing them to get booster shots as necessary, especially if future booster campaigns are planned.”
Moisset also highlighted the importance of caution for patients exhibiting the most severe inflammatory activity, who should receive disease-modifying treatments prior to their booster vaccinations. Those who are untreated or have highly active disease experienced a slightly elevated risk after the third vaccine dose, with the greatest risk observed when both conditions were present.
A limitation of this study is that it only considered relapses that necessitated corticosteroid treatment, meaning milder relapses that were not assessed by neurologists or that did not require corticosteroids were excluded from the analysis.
