Exposing newborn babies to germs could help prevent asthma as they grow up, research suggests.
The findings bolster the theory that modern obsession with hygiene and cleanliness has driven a boom in allergies and health problems.
According to the ‘hygiene hypothesis’, exposure to bacteria is necessary to prime the immune system early in life.
Many scientists believe that modern society, with its mania for sanitation and easy access to antibiotics, makes children hypersensitive to harmless allergens.
The latest work, published last night in the journal Nature Medicine, may lead to bacterial treatments in which germs are intentionally fed to infants.
The scientists found that when newborn mice were exposed to allergens they were better able to ward off asthma.
Other studies have already shown that airway exposure to bacteria can be effective at controlling allergy-driven airway inflammation in adult mice, the scientists said.
The team, led by Dr Benjamin Marsland, from the University of Lausanne in Switzerland, wrote: ‘Our current study indicates that such treatments could be greatly optimised by targeting the narrow developmental window that exists following birth, or by targeting specific molecules.