Yellow Fever Vaccine is Contraindicated in Myasthenia Gravis
The yellow fever vaccine should NOT be given to patients with myasthenia gravis. This is an absolute contraindication established by the Advisory Committee on Immunization Practices (ACIP) 1.
Why This Contraindication Exists
The contraindication stems from documented cases of yellow fever vaccine-associated viscerotropic disease (YEL-AVD), a potentially fatal complication. Specifically, 4 out of the initial 23 reported YEL-AVD cases (17%) occurred in patients who had undergone thymectomies for thymomas 1.
Myasthenia gravis is classified as a thymus disorder associated with abnormal immune cell function, placing it in the same high-risk category as thymoma 1. The thymic dysfunction—whether from the disease itself or from thymectomy performed as treatment—creates an increased risk for severe vaccine-associated adverse events with this live attenuated vaccine.
What to Do Instead
If your patient with myasthenia gravis cannot avoid travel to a yellow fever endemic area:
- Provide a medical waiver exempting them from vaccination requirements 1
- Counsel extensively on mosquito bite prevention measures, including:
- DEET-containing insect repellents
- Permethrin-treated clothing
- Protective clothing (long sleeves, pants)
- Staying in air-conditioned or screened accommodations
- Avoiding outdoor activities during peak mosquito feeding times
Important Nuance: Incidental Thymectomy Exception
There is ONE exception to consider: Patients who underwent incidental surgical removal of the thymus (not for myasthenia gravis or thymoma) or who had remote radiation therapy to the thymus may receive the vaccine if indicated 1. However, this does NOT apply to patients with myasthenia gravis itself, as the disease represents ongoing thymic-related immune dysfunction regardless of whether thymectomy was performed.
Emerging Evidence (Not Yet Standard Practice)
A very recent 2026 case report 2 describes successful yellow fever vaccination in a patient with childhood thymectomy for myasthenia gravis using a novel "proxy immunization" approach with dengue vaccine to first assess immune competence. However, this represents experimental practice requiring specialized immune monitoring and should not change current contraindication guidelines. This approach is not ready for routine clinical application.
Common Pitfall to Avoid
Do not confuse myasthenia gravis with other neuromuscular conditions that may not involve thymic dysfunction. The contraindication is specific to thymus-associated disorders. Also, do not assume that well-controlled myasthenia gravis or long disease remission changes this contraindication—the guideline makes no distinction based on disease activity or treatment status 1.