Individuals diagnosed with multiple sclerosis (MS) sometimes experience apprehension about potential symptom flare-ups or recurrences following vaccination with live attenuated vaccines. This concern can contribute to reluctance in getting vaccinated.
However, a recent investigation published in JAMA Network Open has revealed that MS patients can safely receive live attenuated vaccines for measles, mumps, and rubella (MMR), as well as the chickenpox (varicella) vaccine, without a greater likelihood of experiencing a relapse of their symptoms.
The researchers stated, "The results support the administration of these vaccines when indicated and may help reassure clinicians and patients, reducing vaccine hesitancy.”
Live attenuated vaccines function by introducing a weakened, yet still active, version of a virus. This approach prompts a strong immune response, which then helps the vaccinated individual resist the targeted diseases.
No Increase in Relapses Observed in Vaccinated Individuals
A retrospective cohort study, spearheaded by researchers at the University of Vic–Central University of Catalonia in Spain, examined 369 adult MS patients. From July 2016 to October 2024, 123 participants received at least one dose of the live attenuated chickenpox and/or MMR vaccine, while 246 participants did not receive these vaccines.
The study identified a total of 36 relapses. Of these, 15 (41.7%) occurred in vaccinated individuals, and 21 (58.3%) were in the unvaccinated control group. The analysis indicated that vaccination did not lead to an increase in symptom relapses when compared to the control group.
For the purposes of this study, a relapse was defined as the emergence of new neurological signs or the worsening of existing symptoms that persisted for at least one day following vaccination, and were not attributable to fever or infection. The relapse must have occurred at least 30 days after any preceding relapse.
The authors noted that vaccine uptake remains relatively low among MS patients. This is partly due to fears among some patients and healthcare providers that live attenuated vaccines might provoke new symptoms or exacerbate existing ones. The study’s findings are intended to provide reassurance to MS patients regarding the safety of live attenuated vaccines, particularly in light of ongoing measles outbreaks in both the United States and Europe.
The researchers concluded, "Demonstrating the safety of MMR vaccination, even in a population traditionally perceived as vulnerable, such as people with MS, is therefore highly relevant for both clinical practice and public health policy."