The question is controversial: can certain infections in early childhood prevent the development of atopic disease and respiratory allergies? If so, which types of infections might confer this protective effect?
In the February 12 issue of BMJ, scientists from several research institutions in Rome weighed in with the latest chapter in the ongoing story of the "hygiene hypothesis." In a retrospective case-control study, they closely evaluated 240 men with atopy and 240 controls from a sample of 1659 Italian Air Force cadets.
Voelker R. The Hygiene Hypothesis. JAMA. 2000;283(10):1282. doi:10.1001/jama.283.10.1282