Per-protocol (PP) sample will be defined as ITT sample participants who remain in the study for 12 months and in whom the primary endpoints were assessed. Participants in the PP sample must be compliant with study medication, defined as taking 75% or more of their study medication for the duration of the study. Compliance with study medication will be as assessed by pill count for returned AIT/placebo. Participants in the PP sample will be analysed with the group to which they were randomized. The non-atopics will also be included in the PP sample.