A nurse is collecting data from a client before administering a hepatitis B immunization. The nurse should withhold the immunization if the client is allergic to which of the following substances?

A. Baker's yeast. The hepatitis B vaccine is contraindicated in individuals with a severe allergy to baker’s yeast. This is because the vaccine is produced using Saccharomyces cerevisiae (baker’s yeast), which can trigger an allergic reaction in susceptible individuals. Symptoms of a yeast allergy may include rash, difficulty breathing, and anaphylaxis, requiring the vaccine to be withheld and an alternative plan considered. B. Nuts. Nut allergies are not related to the hepatitis B vaccine, as it does not contain nut-derived ingredients. While nut allergies can be severe and cause anaphylaxis, they do not pose a specific risk in the administration of this vaccine. Therefore, the presence of a nut allergy alone does not require withholding the immunization. C. Wheat. A wheat allergy is not a contraindication for the hepatitis B vaccine. Wheat allergies primarily cause reactions to gluten-containing foods or products but do not have any connection to the components used in the production of the vaccine. The vaccine can be safely administered to individuals with wheat allergies. D. Egg yolk. While some vaccines, such as the influenza vaccine, may be derived from egg proteins, the hepatitis B vaccine is not produced using egg-based components. An allergy to egg yolk does not pose a risk for adverse reactions to this vaccine, so it should not be withheld in individuals with an egg allergy.