During the winter months it always seems that people are "getting sick" more so than during any other time of the year. And why is it that some people are always under the weather and others are not? The answer is in the body's ability to fight off disease, or in other words, the strength of your immune system.
Your immune system is the part of your body that identifies foreign substances such as "bad bacteria", viruses, dust, etc. and stimulates your body to respond by removing these substances from your body.