How you can get genital herpes on your mouth and vice versa

Mike Bohl, MD, MPH, ALM - Contributor Avatar

Written by Linnea Zielinski 

Mike Bohl, MD, MPH, ALM - Contributor Avatar

Written by Linnea Zielinski 

last updated: Feb 01, 2020

4 min read

Big families can be overwhelming. Herpes is actually a family of viruses and a big one at that. In fact, there are over 100 forms of herpesvirus in this extended family, and that can feel, well, like a little much to wrap your head around (Whitley, 1996). But think of it this way: It's like a huge family you invited to a big family reunion, but only a couple showed up. There are only nine types of herpes viruses that affect humans, and one of them does so only extremely rarely. Quite a relief compared to dealing with over 100, right?

Herpes is actually quite misunderstood. Different types of this virus don't just cause sexually transmitted diseases like genital herpes and oral herpes, which you probably know as cold sores. Some of these viruses cause illnesses that you likely had as a child, like mononucleosis (mono) or chickenpox. And herpes is far more common than people think. Almost everyone is infected with some form of the virus, though two types are by far the most common. Herpes simplex virus 1 (HSV-1), which people associate with cold sores, affects an estimated 3.7 billion people under the age of 50 (Looker, 2015). And the World Health Organization also estimates that around 417 million people worldwide between the ages of 15 and 49 have herpes simplex virus 2 (HSV-2), the type commonly associated with genital herpes (Herpes Simplex Virus, 2017).

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Herpes transmission

But figuring out how many people have genital herpes is getting complicated. Serena McKenzie ND, IF, NCMP, Medical Director of the Northwest Institute for Healthy Sexuality, says she's seen a recent 40% increase in type 1 genital herpes outbreaks. That means the type of herpes we typically associate with the mouth is being passed through oral sex and causing more genital herpes cases. Just like many of the other types of herpes can cause more than one illness, sexual health experts are finding that HSV-1 and HSV-2 can't be considered separately by location on the body. Here's what you need to know about herpes transmission, how you can get HSV-2 on your mouth, and how you can get HSV-1 on your genitals.

Can genital herpes be transmitted orally? And, can cold sores lead to genital herpes?

The short answer is yes, and through oral sex. We know the HSV-1 typically causes oral herpes. And we know that HSV-2 typically causes genital herpes. But it turns out these territories on the body are not exclusive. HSV-1 can also cause genital herpes (and this type of infection is exactly what Dr. McKenzie is seeing on the rise). And HSV-2 can also cause oral herpes, although it is rare (Yura, 1991). But this makes sense physiologically. HSV-2 can cause infection in mucosal linings, which aren't just present in your genital areas. They're also present in your mouth and anus. 

So what is needed for any of this to happen? In one word: contact. If your mouth comes in contact with genitals that are infected, or if your genitals come in contact with a mouth that is infected, it doesn't matter which type of HSV it is. There's a chance the infection will spread. And it's worth noting that your partner doesn't have to have lesions to pass HSV-2 to your mouth or genitals. Although the virus is most contagious during an outbreak, Dr. McKenzie points out that viral shedding occurs after the first outbreak even when the virus isn't active. This shedding of herpes virus cells has been observed in both men and women, and it's enough to pass on the infection.

In some rare cases, HSV-1 or HSV-2 may also cause herpes esophagitis, which is a herpes infection in the esophagus. HSV-1 or HSV-2 can cause this condition, although HSV-1 is far more common. But it's extremely rare in people with healthy immune systems (Canalejo Castrillero, 2010).

How to prevent herpes transmission

It's important to keep in mind that nothing is 100% effective against the transmission of herpes. But there are precautions you can take with your partner to diminish the risk of infection. People diagnosed with a herpes infection are sometimes prescribed daily antiviral medication to manage and prevent outbreaks. There are different types of herpes medications, such as acyclovir (brand name Sitavig, Zovirax), valacyclovir (brand name Valtrex), or famciclovir (brand name Famvir). These can all help control herpes symptoms, but they do not completely prevent transmission of the virus.

Before entering into a sexual relationship, partners should consider testing for sexually transmitted infections (STIs) so each person can make an informed decision about contact and take steps needed to cut the risk of transmission. Herpes is not routinely tested for, so you need to be sure to ask for this test specifically. Condoms and dental dams can help prevent the spread of herpes, though neither is 100% effective. Limiting sexual partners or choosing a monogamous relationship can help reduce your risk only in so far as it shrinks the number of people you come into contact with who potentially have HSV-1 or HSV-2. It can also help to avoid sexual contact during herpes outbreaks when it is the most contagious, though herpes can still be passed when the virus is dormant, and the person is asymptomatic. It's important to think about all points of contact, too. "If people are dating, herpes can transmit through sex toy use, which is another factor many people do not consider when they're talking about safer sex," Dr. McKenzie cautions.

If you're in an open relationship, regular screening for STIs by all parties and open communication will help everyone lower their risk of infection. Medical professionals test for herpes infections in several ways. There are different tests for people showing symptoms, but for those looking to find out if they have herpes, medical professionals run a blood test looking for antibodies to the virus. But most of these tests look for IgG, which means it may not pick up if you've been recently infected with the virus.

Valacyclovir Important Safety Information: Read more about serious warnings and safety info.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

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Current version

February 01, 2020

Written by

Linnea Zielinski

Fact checked by

Mike Bohl, MD, MPH, ALM

About the medical reviewer

Dr. Mike is a licensed physician and a former Director, Medical Content & Education at Ro.