The human immune system is like a thermostat: to work efficiently it needs to be properly tuned. If it is “set” to low, there’s a danger that it won’t react to invading viruses and bacteria. If it’s set too high, then it will be hyperactive and start attacking helpful bacteria and healthy cells.
The immune system establishes a delicate balance between the two in childhood, and it does this through exposure to microbes. By coming into contact with various microbes, it learns what is a threat and what is harmless.
LET YOUR KIDS GET DIRTY! (and stop using antibacterial EVERYTHING!)