This common virus causes cold sores, but it doesn't always cause symptoms.
Herpes simplex virus type 1 (HSV-1) spreads easily from person to person through direct contact with skin or contact with saliva.
HSV-1 causes blistering sores around the mouth and lips. These sores are called cold sores, fever blisters, or oral herpes.
HSV-1 can also cause genital herpes, but most cases of genital herpes are caused by a second type of herpes simplex virus, HSV-2.
HSV-1 stays in your body, permanently, in an inactive state once you're infected.
Certain triggers, such as stress, may periodically reactivate the virus and lead to recurrent symptoms and outbreaks.
HSV-1 Prevalence
HSV-1 infection is very common. The World Health Organization estimates that 67 percent of all people in the world younger than 50 have HSV-1.
In the United States, an estimated 54 percent of people between the ages of 14 and 49 have HSV-1.
Most people with HSV-1 become infected during childhood or adolescence.
Not everyone with HSV-1 gets cold sores or has symptoms. Many people with the virus don't even know they're infected.
How Do You Get Cold Sores?
Cold sores are very contagious. HSV-1 is transmitted mainly through mouth-to-mouth contact with an infected person.
HSV-1 can be spread by:
- Kissing
- Sharing a cup or eating utensils
- Sharing lip balm or lipstick
- Sharing a toothbrush, razor, towel, or any other object that may have come into contact with the herpes virus
- Touching an open cold sore
- Oral sex (it's possible to get cold sores from giving oral sex to someone with herpes in the genital area)
It's important to keep your hands clean if you have a cold sore, because cold sores can spread to other parts of the body from the mouth area.
If you have a cold sore, wash your hands carefully before touching yourself or other people. Try not to touch your cold sore too much.
In some people, an HSV-1 infection can spread to:
- Fingertips (especially in children who suck their thumbs)
- Eyes
- Other areas of the skin (people with the skin condition eczema have a higher risk of spreading cold sores to other areas of their body)
When you have a cold sore, avoid the following activities to protect other people from catching the infection:
- Kissing
- Sharing drinks, utensils, or other items that may have touched your lips or saliva
- Giving oral sex
HSV-1 is most contagious when a cold sore is present, but it's still possible to spread HSV-1 to another person even if cold sores aren't present.