Do infections trigger acute Multiple Sclerosis (MS) exacerbations?

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Last updated: February 11, 2025View editorial policy

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From the Guidelines

Infections can trigger acute Multiple Sclerosis (MS) exacerbations.

Evidence for Infection-Triggered Exacerbations

  • The relationship between infections and MS exacerbations is complex, but it is generally believed that infections can trigger an immunological response that may lead to an MS exacerbation 1.
  • However, the evidence from the provided studies does not directly support a strong link between infections and MS exacerbations, with one study focusing on Covid-19 vaccination recommendations and the other on diagnostic criteria for MS 1.

Diagnostic Considerations

  • An MS exacerbation, or "attack," is defined as an episode of neurological disturbance lasting at least 24 hours, with expert clinical assessment to rule out pseudoattacks caused by factors such as infection or changes in core body temperature 1.
  • It is essential to distinguish between true exacerbations and pseudo-exacerbations, which can be caused by infections or other factors, to ensure accurate diagnosis and treatment 1.

Clinical Implications

  • In clinical practice, it is crucial to consider the potential for infections to trigger MS exacerbations and to take a cautious approach when managing patients with MS, particularly those with a history of infections or autoimmune conditions 1.

From the Research

Infections and Multiple Sclerosis Exacerbations

  • Infections have been postulated as a potential trigger for Multiple Sclerosis (MS) exacerbations, with several studies suggesting a link between the two 2, 3, 4, 5, 6.
  • Research has shown that common upper respiratory, gastrointestinal, and urogenital tract infections can trigger MS exacerbations, with upper-respiratory infections doubling the risk of relapse 3, 6.
  • Specific pathogens, such as Epstein-Barr virus (EBV), have been implicated in the development and exacerbation of MS, although the exact mechanisms remain unclear 3, 5.
  • Studies have also demonstrated that MS patients are not at increased risk of infectious disease in the absence of treatment or debility, but that disease-modifying therapies (DMTs) used to treat MS can increase the risk of infections 2.
  • The relationship between infections and MS exacerbations is complex, and further research is needed to fully understand the mechanisms involved and to develop effective strategies for preventing relapses 4, 6.

Key Findings

  • Infections can trigger MS exacerbations, with upper-respiratory infections being a common culprit 6.
  • Specific pathogens, such as EBV, may play a role in the development and exacerbation of MS 3, 5.
  • MS patients are not at increased risk of infectious disease in the absence of treatment or debility, but DMTs can increase the risk of infections 2.
  • Further research is needed to understand the mechanisms involved in the relationship between infections and MS exacerbations 4, 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

The role of infections in multiple sclerosis.

Multiple sclerosis (Houndmills, Basingstoke, England), 2019

Research

Infections and multiple sclerosis.

Handbook of clinical neurology, 2014

Research

Multiple sclerosis and infection: history, EBV, and the search for mechanism.

Microbiology and molecular biology reviews : MMBR, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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