KEY POINTS

Vaccines are important for protection of individual animals and for creation of herd immunity against infectious diseases.

Induction of immune responses to nontarget antigens present in most vaccines can lead to allergic sensitization, particularly in breeds with genetic predisposition.

Reactions to vaccines can vary from allergic events (face swelling) to anaphylactic shock. Although uncommon, such responses can occur.

Autoimmune diseases have a variety of causes and generally have a genetic predisposition. Overvaccination in a patient with a predisposition to autoimmune disease may enhance the likelihood for development of an autoimmune response.