Being careful will make you more vulnerable

We have reached our epitome of hygiene consciousness. We are conscious about small thing, but forget a big thing. Confused? Let me explain you. We waste food even if there is a speck of dust in it, but we forget to wash our hands before eating. Sometimes we get over exaggerated and wash it with all kinds of soaps and hand wash. But even after taking millions of precaution, we still get diseases. We even see children playing in those garbage, eating anything they get, and are more vulnerable to infectious diseases. But still they are lesser affected in case of disease. Is being over careful more vulnerable?
Being careful will make you more vulnerable
The fact:

When we get more and more health conscious, we are lesser prone to diseases. So our immune system gets weaker and weaker. Since we take so much precautions, even if we catch a cold it goes till weeks to get well. The reason behind this? Our immune system is not exposed to it and it does not know how to tackle it. Our immune system works in two ways:

1. Innate
2. Adaptive

The first one is general and it fights against all pathogens. Our concern is now on adaptive. This type of system first recognises the pathogen on first strike and remembers it afterwards. It does not allow you to be attacked by it once again. So when you are not exposing yourselves to external environment then you are sure to suffer more. Our immune system works at its best when we are below 30's. If a new pathogen attacks a person above 40 years, say, and a person below 25, then the person above 40 will suffer more as immune system becomes weak. When you are attacked, the immune system recognises it and adapts it fast. 

The final fact is that if you are trying to restrict yourselves and try to be over conscious then you are going to pay for it. I say, be conscious but not over conscious.