In the version of this article originally published, several competing interests for Erika von Mutius were missing. The following text was added to the Competing Interests section: Erika von Mutius is listed as inventor on the following patents: Publication Number EP 1411977: Composition containing bacterial antigens used for the prophylaxis and the treatment of allergic diseases; Publication Number EP 1637147: Stable dust extract for allergy protection; and Publication Number EP 1964570: Pharmaceutical compound to protect against allergies and inflammatory diseases. Erika von Mutius is listed as inventor and has received royalties on the following patent: Publication Number EP 2361632: Specific environmental bacteria for the protection from and/or the treatment of allergic, chronic inflammatory and/or autoimmune disorders.