Yellow Fever Vaccination in an Individual with Confirmed Egg Protein Allergy: A Case Report

Yellow fever vaccination is recommended for travelers visiting endemic regions in South America and Africa. The live-attenuated vaccine (Stamaril^®, Sanofi Pasteur) is produced in embryonated chicken eggs and contains residual ovalbumin, posing a challenge for individuals with egg protein allergy.

We report the case of a 35-year-old male disaster relief worker with confirmed egg protein allergy and moderate sensitization but no history of anaphylaxis. Under normal circumstances, a statement confirming that vaccination is not possible would be sufficient for entry. However, due to his work-related duties and the relevant guidelines from his employer, there was an urgent need for vaccination despite his egg protein allergy. A comprehensive allergy work-up including skin prick testing, serum-specific IgE, and oral provocation testing revealed a moderate allergy without systemic reactions.

Following informed consent and risk assessment, a fractional dose (0.1 mL) of the reconstituted yellow fever vaccine was administered under close monitoring. The patient developed a localized dermal reaction without systemic symptoms. Post-vaccination neutralization testing confirmed seroconversion indicating protective immunity.

Although yellow fever vaccination is considered contraindicated in individuals with severe egg protein allergy, the literature supports its cautious use in selected cases. Fractional dosing has emerged as an effective dose-sparing strategy. Studies show that even in egg protein-allergic individuals, adverse events are rare.

In this case, a fractional yellow fever vaccination was safe and an effective option for an egg-allergic individual in a high-risk occupational setting, supporting a personalized approach based on clinical risk assessment and current evidence.