I have switched to Xlear, it has kept colds at bay for a couple of years now. I am one of those who gets every cold that comes my way. I have gotten to the point where I know that I have had exposure by early recognition of symptoms. First line of defense is the nasal spray, rinse the sinus with saline solution, gargle with saline and Listerine. A couple of days of this, and it passes me by. My housemates will get the 14+ day snotting and coughing, but my system works. Thanks to those at Zicam and Xlear, and Vit D3, C and others.