A nurse in a community health clinic is administering seasonal inactive influenza vaccine. Before administering it, the nurse must confirm that the client is not allergic to which of the following?

A. Some vaccines may contain gelatin as a stabilizer, and clients with a known gelatin allergy should be evaluated. However, the seasonal inactivated influenza vaccine does not typically contain gelatin in amounts that cause concern, so this is not the primary allergy check. B. Yeast allergy is important to consider with vaccines like hepatitis B, which are produced using yeast. Seasonal influenza vaccines, however, are not yeast-based, so yeast allergy is not a major concern in this context. C. Shellfish allergy is relevant for certain contrast media or iodine-containing products, but it is not a contraindication for the influenza vaccine. There is no risk of a reaction due to shellfish proteins. D. Most seasonal inactivated influenza vaccines are produced using egg-based technology, meaning the vaccine may contain trace amounts of egg protein. Clients with a known severe egg allergy are at risk for anaphylaxis. Therefore, the nurse must confirm that the client does not have a significant egg allergy before administration. In cases of mild egg allergy, some vaccines may still be administered under supervision per CDC guidelines.