BCG for the prevention of food allergy — exploring a new use for an old vaccine

BCG has profound immunomodulatory effects that may reduce the risk of food allergy in children

The prevalence of allergic disease in developed countries has risen dramatically since the mid 20th century and Australia now has the highest documented prevalence of childhood food allergy in the world.1 Theories to explain this rise include changes in the timing of food introduction, epigenetic changes related to environmental factors, and alterations in micronutrient status (particularly of vitamin D). Interactions between the human microbiome, microbial exposures during infancy and the developing immune system are particularly important. According to this model, termed the “hygiene hypothesis” or, more recently, “biome depletion”,2 immune system development may be influenced not only by infections, but also by exposures to animals and antibiotics, and through birth by Caesarean section.