Is the yellow fever vaccine safe for a multiple sclerosis (MS) patient not taking immunosuppressive agents?

Yellow Fever Vaccination in MS Patients Not on Immunosuppressive Therapy

Yellow fever vaccination is safe for MS patients who are not taking any immunosuppressive medications, with no increased risk of disease worsening compared to non-vaccinated MS patients. 1

Safety Profile for Non-Immunosuppressed MS Patients

• Recent evidence from a 2021 study showed that the 1-year annualized relapse rate following yellow fever vaccination did not differ between vaccinated MS patients (0.219) and non-vaccinated MS patients (0.208), suggesting the vaccine does not worsen the course of relapsing-remitting MS 1

• The yellow fever vaccine is a live attenuated vaccine, which generally requires caution in immunocompromised individuals, but MS itself without immunosuppressive treatment does not constitute immunocompromise 2, 3

Conflicting Evidence and Risk Assessment

• There is some conflicting older evidence from a small 2011 study (n=7) that suggested an increased relapse rate after yellow fever vaccination in MS patients 4

• However, more recent and larger studies have contradicted these findings:

  • A 2020 self-controlled case series of 23 MS patients found that yellow fever vaccination was associated with neither an increase in MS relapse nor emergence of new brain/spinal lesions 5
  • The 2021 study with 128 relapsing-remitting MS patients provides the strongest evidence that yellow fever vaccination does not worsen MS disease course 1

Important Considerations and Precautions

• The decision to administer yellow fever vaccine should consider:

  1. Travel necessity to yellow fever endemic areas
  2. Current MS disease activity (stable vs. active)
  3. Absence of immunosuppressive medications

• Absolute contraindication: MS patients on immunosuppressive therapies, particularly anti-CD20 antibodies, should not receive yellow fever vaccine due to documented cases of vaccine-derived yellow fever infection 6

Timing Considerations

• If the patient has recently discontinued immunosuppressive therapy, follow these waiting periods before administering yellow fever vaccine 2:
  • Steroids: 1 month after discontinuation
  • Thiopurines: 3 months after discontinuation
  • Anti-TNF agents: 3 months after discontinuation
  • Other biologics: 3-4 months after discontinuation

Practical Approach

1. Confirm the patient is not on any immunosuppressive medications
2. Verify MS disease is stable (not in active relapse)
3. Administer yellow fever vaccine at least 4 weeks before travel to endemic areas
4. Monitor for standard vaccine side effects (fever, headache, myalgia)
5. Continue routine MS monitoring as per regular care plan

Conclusion

Based on the most recent and highest quality evidence, yellow fever vaccination appears safe for MS patients not taking immunosuppressive medications. The benefit of protection against potentially fatal yellow fever infection outweighs the theoretical risk of MS exacerbation when traveling to endemic regions.