Prevention of the Common Cold is done mostly by common sense. Good handwashing techniques are the most important. There are bacterial soaps available at your local pharmacy that can be used without water. A lot of medical clinics use them because it eliminates the need for a sink. It is very valuable for my wife as a visiting nurse.
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http://www.thebostonchannel.com/health/2524648/detail.html?treets=bos&tml=bos_health&ts=T&tmi=bos_health_1_12150010032003