What are the contraindications for the yellow fever vaccine?

Contraindications for Yellow Fever Vaccine

Yellow fever vaccine is absolutely contraindicated in infants younger than 6 months, persons with thymus disorders associated with abnormal immune cell function, severe immunosuppression due to HIV/AIDS (CD4 <200/mm³), primary immunodeficiencies, malignancies, transplantation, and those on immunosuppressive medications. 1

Absolute Contraindications

Age-Related Contraindications

• Infants younger than 6 months of age due to significantly elevated risk of yellow fever vaccine-associated neurotropic disease (YEL-AND) 1
• Infants 6-8 months should be considered a precaution (not absolute contraindication), with vaccination decisions made on a case-by-case basis 1, 2

Immune System Disorders

• Thymus disorders associated with abnormal immune cell function (e.g., thymoma, myasthenia gravis) 1, 3
• Persons with AIDS or symptomatic HIV infection 1
• HIV-infected individuals with CD4 counts <200/mm³ (or <15% of total lymphocytes for children <6 years) 1
• Primary immunodeficiencies 1, 3
• Malignant neoplasms 1, 3
• Transplantation recipients 1, 3
  • Solid organ or hematopoietic stem cell transplant recipients within 2 years of transplantation 1
  • Transplant recipients >2 years post-transplant who are still taking immunosuppressive medications 1

Medication-Related Contraindications

• Immunosuppressive or immunomodulatory therapies 1:
  • High-dose systemic corticosteroids (≥2 mg/kg/day or ≥20 mg/day of prednisone or equivalent for ≥2 weeks) 1
  • Alkylating drugs 1
  • Antimetabolites 1
  • TNF-α inhibitors (e.g., etanercept) 1
  • IL-1 blocking agents (e.g., anakinra) 1
  • Monoclonal antibodies targeting immune cells (e.g., rituximab, alemtuzumab) 1, 4

Hypersensitivity

• Severe hypersensitivity to vaccine components, including egg proteins 1

Important Exceptions and Clarifications

Corticosteroid Use That Does NOT Contraindicate Vaccination

Yellow fever vaccine can be administered in the following circumstances 1:

• Short-term corticosteroid use (<2 weeks) 1
• Low-to-moderate dose (<20 mg prednisone or equivalent per day) 1
• Long-term alternate-day treatment with short-acting preparations 1
• Maintenance physiologic doses (replacement therapy) 1
• Topical administration (skin, eyes), inhaled, or intra-articular, bursal, or tendon injections 1

HIV Infection With Adequate Immune Function

• HIV-infected individuals with CD4 counts >200/mm³ and without symptoms may receive the vaccine, though they should be monitored closely 5, 2

Thymus Conditions That Do NOT Contraindicate Vaccination

• Incidental surgical removal of the thymus 1
• Remote history of radiation therapy to the thymus 1

Clinical Management When Vaccination is Contraindicated

For patients with contraindications who must travel to yellow fever endemic areas 1:

• Provide a medical waiver 1
• Emphasize protective measures against mosquito bites 1
• Consider delaying travel if possible, especially for infants 6-8 months 1

Special Considerations

Pregnancy and Breastfeeding

• While traditionally considered a precaution, recent evidence suggests the vaccine may be safe during pregnancy, particularly in the first trimester 2
• Decisions should be made on a case-by-case basis, weighing the risk of exposure to yellow fever against potential vaccine risks 2

Egg Allergy

• For egg-sensitive individuals, skin testing can be performed before vaccination 1
• If vaccination is necessary despite severe egg sensitivity, desensitization protocols under direct supervision of a physician experienced in anaphylaxis management can be implemented 1, 2

Post-Vaccination Monitoring

• All vaccine recipients should be observed for at least 15 minutes following administration 1
• Epinephrine (1:1000) should be readily available to manage potential anaphylactic reactions 1