What Is HSV-1?
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, 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 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.
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:
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:
When you have a cold sore, avoid the following activities to protect other people from catching the infection:
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.
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