Microbial exposures that establish immunoregulation are compatible with Targeted Hygiene.

Rook, Graham A W; Bloomfield, Sally F

It is often suggested that hygiene is not compatible with the microbial exposures that are necessary for the establishment of the immune system in early life. However, when we analyse the microbial exposures of modern humans in the context of human evolution and history, it becomes evident that, whilst children need exposure to the microbiotas of mothers, other family members and the natural environment, exposure to the unnatural microbiota of the modern home is less relevant. In addition, any benefits of exposure to the infections of childhood within their household setting are at least partly replaced by the recently revealed non-specific effects of vaccines. This paper shows how targeting hygiene practices at key risk moments and sites can maximize protection against infection whilst minimizing any impact on essential microbial exposures. Moreover this targeting must aim to reduce direct exposure of children to cleaning agents since these probably exert Th2 adjuvant effects which trigger allergic responses to normally innocuous antigens. Finally, we need to halt the flow of publications in the scientific literature and the media that blame hygiene for the increases in immunoregulatory disorders. Appropriately targeted hygiene behaviour is compatible with a healthy lifestyle that promotes exposure to essential microorganisms.