Human papilloma virus vaccines
HPV vaccines may contain residues of yeast. Individuals with a history of severe allergy to yeast could theoretically experience a severe allergic reaction after administration of this vaccine45. Therefore, in case of yeast allergy, it is recommended to perform a complete allergy evaluation.
Some brands of HPV vaccines contain PS80 as stabilizer, which might be responsible for hypersensitivity reactions46. Children that experienced a severe allergic reaction to this substance should be vaccinated with formulations that do not contain PS80 or should be addressed to a specialized allergy center to perform skin tests and prescribe the protocol of vaccination as described in the diagnostic work-up.