Vaccine allergies.

Currently, the increasing numbers of vaccine administrations are associated with increased reports of adverse vaccine reactions. Whilst the general adverse reactions including allergic reactions caused by the vaccine itself or the vaccine components, are rare, they can in some circumstances be serious and even fatal. In accordance with many IgE-mediated reactions and immediate-type allergic reactions, the primary allergens are proteins. The proteins most often implicated in vaccine allergies are egg and gelatin, with perhaps rare reactions to yeast or latex. Numerous studies have demonstrated that the injectable influenza vaccine can be safely administered, although with appropriate precautions, to patients with severe egg allergy, as the current influenza vaccines contain small trace amounts of egg protein. If an allergy is suspected, an accurate examination followed by algorithms is vital for correct diagnosis, treatment and decision regarding re-vaccination in patients with immediate-type reactions to vaccines. Facilities and health care professionals should be available to treat immediate hypersensitivity reactions (anaphylaxis) in all settings where vaccines are administered.