For patients allergic to egg, gelatin, or thimerosal, which vaccine should be avoided?

The influenza vaccine should be avoided in patients who have a history of severe allergic reactions to eggs. This is primarily because the virus used in most influenza vaccines is grown in hen's eggs, which can lead to the potential presence of egg proteins in the final vaccine product. In patients with egg allergies, particularly those who have experienced an anaphylactic reaction to eggs, there is an increased risk of adverse reactions following vaccination with traditional influenza vaccines.

While there are certain formulations of the influenza vaccine that are egg-free and can be safely administered to individuals with egg allergies, the standard recommendation is to carefully assess the type of influenza vaccine being used. In general, providers should consult with an allergist or a specialist when determining vaccination strategies for patients with a known egg allergy.

The other vaccines mentioned—pneumococcal, meningococcal, and MMR vaccines—do not typically contain egg-derived components and are considered safe for administration in patients with egg allergies. Therefore, the avoidance of the influenza vaccine is specifically indicated for those with severe egg allergies.