Children exposed to pets, viruses and dust (Clin Exp Allergy, 1999; 29: 611-7; BMJ, 2001; 322: 390-5; Lancet, 2000; 35: 1680-3) at an early age have less asthma as they get older. This is because these things act as small, manageable challenges to the immature immune system.
Such scientific evidence calls into question the accepted wisdom of sterilisation, the use of antibacterial soaps and keeping children away from their sick friends.
Indeed, it appears that early exposure to bacteria is more likely to be health-enhancing if the child’s health is well-supported in other ways - such as breastfeeding and a staged diet free of other known food allergens, like cow’s milk and wheat, too early in life.