When my first born baby boy was only 14 months old we welcomed our second son into the world. My oldest had gotten through his first year illness-free. My second didn't fare so well. Once this little baby was two months old I started inviting my older son's playmates over for play dates. It was, of course, winter and cold and flu season was in full swing. My poor little guy was getting one runny nose after another and at three months old he ...