In the past few days, media representatives have flocked around the carcass of the hygiene hypothesis, apparently believing that they were witnessing the passing of this decades-old idea.
Following the release of details about a single new study, an unprecedented number of news outlets ran articles declaring the demise of the hypothesis which had proposed that the increasingly germ-free surroundings of modern life are contributing to the recent increase in allergies, asthma and autoimmune diseases.
The study in question has found that, contrary to what some previous studies have suggested, children who enter the bacteria-rich environment of daycare at an early age may not have a reduced risk of allergies and asthma in later childhood.
The most objective comment on the new research has been provided by NHS Choices. Other media reports of the research include: Reuters, EurekAlert, BBC News, The Daily Telegraph, Science Daily, Medical News Today, The Nursing Times, The National Examiner, and The Los Angeles Times.
What none of the reporters involved seem to have realised is that the hygiene hypothesis was already dead, having been superseded by a new ‘old friends hypothesis’ which emphasizes the need for exposure not just to infectious bacteria, but to a particular range of organisms with which our species has coexisted throughout its evolutionary history – notably harmless microorganisms from soil, untreated water, fermenting vegetable matter and, critically, parasitic worms.
Not a single one of the above media reports mentions the old friends hypothesis!
NB: This post is not intended to provide medical advice, diagnosis or treatment.