What Is the Herpes Simplex Virus?

Medically Reviewed by Zilpah Sheikh, MD on October 30, 2023
8 min read

Herpes is a common infection caused by herpes simplex viruses. It can cause painful blisters that come and go, usually around the mouth and genitals. Many people who are infected don’t know it. It’s rarely a serious health risk.

What percentage of people have herpes?

In the United States, about 48% of teens and adults under age 50 have herpes simplex virus type 1 (HSV-1), the kind that most often causes mouth sores. About 12% have herpes simplex virus type 2 (HSV-2), the kind that most often causes genital sores. Worldwide, the numbers are higher: 67% for HSV-1 and 13% for HSV-2. Herpes infections last for life, so most older adults worldwide likely have herpes simplex. 

Canker sores vs. herpes

Canker sores are mouth sores often confused with herpes, but they are different. Canker sores are inside your mouth, while sores caused by herpes can be inside or outside your mouth. Canker sores usually show up as round white or yellow sores surrounded by a red ring. They can be on your inner lip, inner cheeks or tongue. You can’t pass canker sores to another person.

Cold sores vs. herpes

"Cold sore" is a common name for a mouth sore caused by herpes, usually HSV-1. You most often see cold sores on the outside of your mouth, around the lips. Some people also get cold sores inside, on the roof of the mouth, the tongue, and gums. They look different from a canker sore and usually erupt in clusters of small blisters filled with fluid. Some people call these fever blisters.

Are cold sores always herpes?

Yes, true cold sores always are caused by herpes viruses. 


Genital herpes

When you have genital herpes, you can get sores around your vagina, penis, or anus. Sometimes they show up on your butt or your thighs. Some people with genital herpes never get symptoms or get symptoms so mild that they might just think they have a pimple or ingrown hair. Others get painful, obvious outbreaks. You can get outbreaks over and over again.

Oral herpes

When you have oral herpes, you can get sores around your mouth. You might get them elsewhere on your face, too. The sores might clear up and return later. 

HSV-1 vs. HSV-2

HSV-1 is the most common herpes simplex virus. Many people get it early in life. In most people, it either causes no symptoms or causes cold sores around their mouth. But sometimes HSV-1 causes genital herpes. That can happen during oral sex, for example.

HSV-2 is less common. It’s most often the cause of genital herpes.

Both viruses spread from person to person during skin-to-skin touching or through body fluids. Both infections last for life. You can have either without knowing it. When you have an active herpes infection, with sores or invisible viruses shedding from your skin, you can pass it on. Most often, the viruses are not active, meaning they aren’t causing you any trouble and can’t spread to other people.

How you get HSV-1

You can pick up this virus as a baby or toddler. That can happen when infected adults, who may have no symptoms, kiss and touch small children. At any time of life, you can get it from touching, kissing, or sharing personal items, such as lip balm and razors. You also can get an HSV-1 infection on your genitals during oral sex.

How you get HSV-2

You're most likely to get HSV-2 by having vaginal or anal sex with an infected person. The viruses can be on skin and in genital fluids, even if you don't see sores. Some people get HSV-2 by performing oral sex on someone with the infection. Babies sometimes get an HSV-2 infection during birth. 

Can you get genital herpes from kissing?

No, you can’t get genital herpes from kissing someone on the mouth. You can get oral herpes that way. You can get genital herpes if someone performs oral sex on you and oral herpes if you perform oral sex on someone else. 

What causes repeated outbreaks?

Once you have either form of herpes simplex, you can get repeated outbreaks, though they tend to get milder and come less often over time. Repeat outbreaks are more common with HSV-2 than HSV-1. Stress, illness, fevers, sun exposure, menstrual periods, and even surgery can trigger outbreaks in some people.

Sometimes herpes is invisible. You could have active herpes simplex virus in your saliva and on your skin with no noticeable symptoms.

Early signs of herpes

When a herpes outbreak is coming, you might notice some symptoms before you see any sores. The skin around your mouth or genitals may tingle, itch, or burn for a day or so. The area also might get red and swollen. If you have genital herpes, you might also get tingling or shooting pains in your legs, hips, or buttocks.

Signs of oral herpes

With your first outbreak, you might get sores inside your mouth. More often, herpes shows up on the edges of your lips or under your nose. You might see clusters of blisters with fluid inside. Then, the blisters will start to leak and form painful sores. After a few days, the blisters crust over, then start healing. During the outbreak, you might get swollen glands in your neck.

Signs of genital herpes

You might see bumps or blisters around your genitals or anus. The blisters may start to ooze fluid and hurt. After a few days, they scab over and start to heal. During the outbreak, it might hurt to pee and you might get discharge from your penis or vagina. Some people get swollen glands in the groin.

Other symptoms

When you have an outbreak of oral or genital herpes, you can get other symptoms, especially the first time it happens. Those might include a fever and body aches. Some people get herpes simplex infections in their eyes, by touching a herpes sore and then their eyes. This most often happens with HSV-1.

Your doctor may be able to tell you have herpes just by looking at the sores during an outbreak. To make sure, they can swab some of the fluid from a blister and send it to a lab. If you're between outbreaks or worried that you might be at risk, you might get a blood test. But those blood tests have limits. They might not pick up an infection that just happened. And if they do show an infection, they can’t tell you how long ago it happened.

The CDC recommends testing for people with possible genital herpes symptoms. Testing also can make sense for people who’ve had a sex partner with genital herpes. Most people don’t have to get tested.

How long can you have herpes without knowing?

You can have herpes simplex viruses in your body your whole life without knowing. In fact, that’s the case for many people. What happens is that the virus moves from surface skin cells to nerve cells, where it hides out without causing any trouble, unless something triggers an outbreak. 


Herpes sores usually go away without any treatment. But treatment can make people feel better sooner. The usual treatments are antivirals – drugs that target the virus. These medicines come in creams and ointments that can relieve burning and itching. They also come in pills and shots that shorten an outbreak.

People who often have genital outbreaks sometimes decide to take antiviral pills every day. That can cut the number of outbreaks and lower the risk of spreading the infection to a sex partner.

How to heal herpes sores faster

The best way to speed up healing is to use an antiviral drug. But home remedies can make you feel better sooner too.

For genital sores, warm baths can be soothing. Between baths, you should keep the area dry. It’s a good idea to wear cotton underwear. For pain relief, you can try ice packs and over-the-counter painkillers like ibuprofen or acetaminophen.

For mouth sores, you can try pain relief creams you find in the dental area of the drugstore. Look for products containing lidocaine or benzocaine. Cold compresses can feel good, too. You can use lip balm to moisturize sore lips – just be sure to throw out that balm after the breakout. And don’t pick at the sores; that can slow down healing.

There is no cure for herpes simplex. Once you have the virus, it stays in your body. The virus lies inactive in nerve cells until something triggers it to become active again.

Is herpes dangerous?

For most people, herpes simplex infections aren't dangerous, even if they cause a lot of outbreaks. But a herpes simplex infection can be more serious for newborn babies and people with weak immune systems. If you're pregnant, have had a transplant, or have cancer or HIV, let your doctor know right away if you have possible herpes symptoms.

People with poor immunity can get complications like a herpes simplex infection of the esophagus, the tube that connects your throat and stomach. That’s called herpes esophagitis. Their outbreaks can also come more often, with worse sores. In newborns, a herpes infection can cause brain inflammation and spread through the body, creating a life-threatening situation. 


Herpes simplex infections are common, but not serious for most people. Many infected people never have symptoms. Herpes simplex virus 1 (HSV-1) usually causes symptoms around the mouth; herpes simplex virus 2 (HSV-2) usually causes symptoms around the vagina, penis, or anus.

Herpes simplex infections are not curable, but herpes outbreaks are treatable and manageable.

  • Can you get herpes from sharing a drink?

That’s possible, because herpes viruses can be in saliva. But it’s not one of the main ways the virus spreads. You usually need skin-to-skin contact or direct contact with someone’s saliva or genital fluids to get infected.

  • Does herpes live on surfaces?

The virus might live on some surfaces for a few hours to a few days. But it’s easily killed by common household cleaners, like bleach and rubbing alcohol. More importantly, there’s no evidence people get infected through toilet seats, bedding, or other surfaces.

  • What’s the difference between genital herpes and genital warts?

Both are spread through skin-to-skin contact, but they're caused by different viruses and are treated with different drugs. The bumps you get with genital warts usually aren't painful, and they don't turn into open sores.

  • How does genital herpes affect pregnancy?

If you get genital herpes for the first time during your pregnancy, you might spread the virus to your baby during the delivery. If you were infected in the past, there’s still some risk, but it’s lower. Most babies don’t get infected. 

If you have genital herpes, you might need to take antiviral medicine near the end of your pregnancy. If you have herpes sores or other signs of infection near delivery, your doctor might suggest a cesarean section to lower risks for the baby. 

  • Do condoms prevent genital herpes?

Condoms can lower your risk, but they may not protect you completely. That’s because condoms might not cover all the skin that has herpes sores or active viruses. 

  •  How do you lower your risk of passing on genital herpes?

Some people take an antiviral medicine every day to lower the risk. You also can avoid having vaginal, anal, or oral sex when you have herpes symptoms. It's important to talk with your doctor and sex partners about managing the risks.