Image of a cold sore

What are cold sores

Cold sores, also known as fever and sun blisters, are caused by herpes simplex virus – Type 1. Most people get HSV-1 during infancy or childhood from a family member or friend. It can be transmitted by kissing or sharing eating utensils or towels.

HSV-1 is extremely contagious. In fact, 67% of the world population under age 50 has HSV-11


1. Herpes simplex virus. World Health Organization. (2016, January). Retrieved October 12, 2017 from