A recent study published in JAMA Network Open offers reassuring news for individuals diagnosed with multiple sclerosis (MS). Concerns about live attenuated vaccines, such as the measles, mumps, and rubella (MMR) and chickenpox (varicella) vaccines, potentially intensifying or reactivating MS symptoms have sometimes led to vaccine hesitancy among these patients.
However, this research indicates that MS patients can safely receive these vaccines without an increased risk of symptom relapse. The study’s authors stated, "The results support the administration of these vaccines when indicated and may help reassure clinicians and patients, reducing vaccine hesitancy."
Live attenuated vaccines work by introducing a weakened, but still live, version of a virus. This triggers a robust immune response, equipping the recipient to fight off the targeted diseases.
No Increased Relapses Observed in Vaccinated MS Patients
The retrospective cohort study, conducted by researchers at the University of Vic–Central University of Catalonia in Spain, analyzed data from 369 adult MS patients. A subset of 123 individuals had received at least one dose of the live attenuated chickenpox vaccine and/or MMR vaccine between July 2016 and October 2024, while 246 individuals had not received these vaccines.
During the study period, 36 relapses were recorded. Of these, 15 occurred in vaccinated individuals and 21 in unvaccinated controls. Crucially, the findings demonstrated that vaccination did not lead to a higher rate of symptom relapses compared to the group that did not receive the vaccines.
For the purposes of this study, a relapse was defined as the appearance of new neurological signs or the worsening of existing symptoms lasting for a day or more post-vaccination, provided fever or infection were absent. The relapse also needed to occur at least 30 days after any prior relapse.
The study authors highlighted that vaccine uptake remains relatively low among MS patients. This is attributed to the apprehension among some patients and healthcare providers regarding the potential for live attenuated vaccines to trigger new symptoms or exacerbate existing ones. The researchers hope these findings will alleviate concerns about the safety of live attenuated vaccines for MS patients, particularly in light of recent measles outbreaks in 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."