Being too clean is also not healthy. In Nepal, the excess of bad germs (compared to a country like the USA) actually helps to build anti-bodies. Fighting anti-bodies helps to build the immunity system. When Westerners are introduced too quickly to an environment so different from them, they can have a "hard landing." A "hard landing" is when you are introduced so quickly to germs that your body does not have time to naturally build anti-bodies. This is where vaccination comes in.
I was reading this post about the Buddha and the Sociopath.
Every individual expels their personal energy to create their individual brand of culture. The kind of culture that the Buddha creates in society is so different from the culture that surrounds the sociopath. There are good germs and there are bad germs in the human body. Both are continually present. Both bring a different energy to the social body.
The Buddha expels good germs in the social body, the Sociopath expels bad germs. Disease happens when the proportion of bad germs increases in proportion to the health of the body as a whole. White-blood cells work in cooperation against germs. The body generates white-blood cells when it detects more germs than it thinks it can handle. The white blood cells are the army of the body. But in the same way that being in a continual state of war can drain a nation's coffers, a body that has to continually generate too many white-blood cells, can drain the body of resources. But fighting against germs in normal circumstances is not bad. In fact, a certain degree of working in cooperation to fight bad germs actually helps society become stronger.
When your immune system is down because of poor nutrition, exercise and sanitation.
If you live too clean a lifestyle, it can hurt your immune system. Fighting bad germs can build your immune system. Your strength to fight bad germs comes from good nutrition, exercise, emotional well-being and sanitation.