For more than 15 years, I wondered why some people apparently never have a common cold infection. Whenever yet another cold infection made me feel miserable, I couldn't help but feel great envy towards those who have been cold-free for years. Today, I am one of them. But contrary to those who have been naturally cold-free for the greater parts of their lives, I had to work hard for it. For years, I've struggled with the common cold, desperately seeking for ways to prevent it. It was a time of great challenges during which I felt as if I was fighting an enemy that could not be...