QUESTION: Are cold sores caused by the same virus that causes colds?
ANSWER: Cold sores are caused by the herpes simplex virus, not by one of the over 200 viruses that leads to colds. People infected with herpes simplex tend to have flare-ups when their immunity is lowered such as during illness or stress. Not infrequently, the herpes infection will cause a mouth sore during or after a bad cold or flu hence the association and the name.
