What Is HSV-1?

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, according to MedlinePlus.

HSV-1 stays in your body, permanently, in an inactive state once you’re infected.

Certain triggers — such as stress, sun exposure, an injury to the affected area, having another infection such as cold, or hormonal changes (like a period) — 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.

An estimated 50 to 90 percent of Americans have HSV-1, according to Johns Hopkins Medicine.

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 eczema have a higher risk of spreading cold sores to areas of their body already affected by the skin condition)

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.