Cold viruses on a surface or on the hands can remain active for several hours, and a person who has a cold can be contagious for some time before and after the signs of illness are obvious.
وتوجد تدابير وقائية اخرى تشمل اتِّباع نظام غذائي متوازن والانتباه خصوصا عند وجود الاولاد .‏ ولماذا ؟‏