A new Thorax review finds
The hypotheses have arisen from a desire to explain epidemiological differences, and those such as the “hygiene” hypothesis had a seemingly corroboratory immunological explanation. However, they have not taken us to the point where we can proudly announce a primary preventive strategy.
I agree with the last statement but have
severe doubts on any “immunological explanation” (that is most likely at the intellectual level of Jerne’s antiidiotypic network theory).
There is even corroborating evidence that the hygiene hypothesis is misleading if we believe in the results of a new Australian study (and there are no reasons why we should not believe in that)
Children tested at age 8 and born in the pollen season, a EURI [early upper respiratory tract infection] … was associated with an increased risk of ryegrass sensitization (OR 5.80 95% CI 1.07, 31.31) but not for children with a EURI born outside the pollen season (OR 0.62 95% CI 0.35, 1.08). … These findings suggest that early life viral URI interacts with ryegrass allergen exposure in the development of ryegrass allergen sensitization and ryegrass sensitized hay fever symptoms.