<a href=https://explorable.com/cause-and-effect>Establishing Cause and Effect</a>. Cause and effect is one of the most commonly misunderstood concepts in science and is often misused by lawyers, the media, politicians and even scientists themselves, in an attempt to add legitimacy to research.
You can't catch cancer from anyone, in any way. Cancer is not contagious. You can't catch HIV/AIDS just by touching somebody. The AIDS virus is not found in sweat. Yes, you can catch a cold, or the flu by shaking hands with someone if you then put your hands on/near a mucous membrane (eyes, nose, mouth).
To curb the spread of the virus it is very important to wash your hands often if you have a cold sore. Not only can you spread the virus to other people but you can spread the virus around to other parts of your own body if for example you touch your cold sore and then rub your eyes or touch your genitals.