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.