Novel vaccines protecting against the development of allergic disorders: a double-edged sword?

The severity and incidence of allergic disorders is steadily increasing despite the widespread use of steroids and other drugs. Recent results obtained in animals suggest that it may be possible to develop novel anti-allergy vaccines for human use, thereby stopping this alarming worldwide increase in allergic diseases. The most promising approaches are the induction of allergen-specific T helper 1 or allergen-specific T regulatory responses. However, both approaches potentially harbour negative side effects that need to be ruled out before vaccinating young children -- the best candidates for the primary prevention of allergic disorders.