The objective of this survey was to evaluate the effect of successful prevention of common infections in child day care centers on the later development of allergic diseases. This was a prospective follow-up survey with a questionnaire administered 12 years after a controlled randomized hygiene intervention.The survey concluded that the prevention of common respiratory tract and enteric infections during early childhood does not change later allergic morbidity. Arch Pediatr Adolesc Med. 2007;161(10):972-7.