Although there is increasing evidence that exposure to harmless microbes during infancy may be protective against development of allergy, it is proving difficult to pinpoint which microbes, at what time, and by which route this exposure should occur. Researchers at the University of Gothenburg report that parental sucking on the baby's pacifier may give significant protection against allergy development.
In a group of 184 children, researchers registered how many infants used a pacifier and how the parents cleaned it. Most parents rinsed the pacifier in tap water before giving it to the baby, some parents also boiled the pacifier to clean it, whilst others had the habit of putting it into their mouth to clean. It was found that children of parents that habitually sucked the pacifier were three times less likely to suffer from eczema at 1.5 years of age, compared with children of parents who did not do this. Importantly, no more upper respiratory infections were seen in children whose parents sucked on their dummies.
The researchers believe that oral commensal microbes are transferred from parent to infants when they suck on the same pacifier. They argue that early establishment of a complex oral microflora could promote healthy maturation of the immune system, thereby counteracting allergy development. The research team has previously conducted large-scale studies on the gut microbiota in relation to allergy development and showed in 2009 that a complex gut microbiota very early in life reduces the risk of allergy development. The onlione version of this paper is at http://pediatrics.aappublications.org/content/early/2013/04/30/peds.2012-3345