Individuals with multiple sclerosis (MS) face a heightened risk of severe COVID-19 infection, yet there have been concerns about the potential for disease relapse following vaccination. A recent study indicates that the risk of relapse post-COVID-19 vaccination may not be significantly elevated for most individuals with MS. The findings are detailed in the August 14, 2024, online edition of Neurology.
According to study author Dr. Xavier Moisset from Clermont Auvergne University in France, those with MS are more vulnerable to severe COVID-19 due to motor disability or the immunosuppressive treatments they often undergo.
Previous research had suggested a link between vaccinations and subsequent relapses, which led some individuals to forgo recommended booster doses. However, this current study found no significant increase in relapse risk post-vaccination for nearly all participants.
The study did identify a slight uptick in relapse risk among patients exhibiting high MS activity—specifically, those who experienced at least two relapses in the prior two years and were not receiving MS treatment.
A total of 124,545 MS patients in France participated in the study, with an average MS diagnosis duration of 14 years. They were monitored for 45 days post-vaccination, since most vaccine-related relapses occur within 28 days.
Out of the participants, 82% (102,524) received at least one COVID-19 vaccine dose, with 95% receiving a second dose and 59% obtaining a booster. The vaccines administered included Pfizer BioNTech, Moderna, AstraZeneca, and Janssen.
During the observation period, researchers specifically analyzed relapses that necessitated treatment with high-dose corticosteroids. After accounting for various influencing factors such as seasonality and the use of disease-modifying therapies, it was determined that COVID-19 vaccination did not elevate the risk of severe relapse, a conclusion consistent across all vaccine doses.
To validate their results, researchers compared incidences of relapse among those vaccinated with those who did not experience a relapse, further confirming no increased risk associated with vaccine exposure. Interestingly, they observed a slight reduction in relapse risk following vaccination.
Dr. Moisset expressed optimism about the findings, stating that they support the safety of vaccines for individuals with MS, allowing them to receive booster shots as necessary.
He cautioned, however, that patients with the most severe inflammatory activity should first undergo disease-modifying treatment before receiving a booster, as untreated patients or those with highly active disease experienced a minor increase in relapse risk following the third vaccine dose, especially when both factors were present.
A limitation of this study is its focus solely on relapses that required corticosteroid treatment, meaning milder relapses that did not necessitate medical intervention were not included in the analysis.