HSV-1 vs. HSV-2: What’s the Difference?

They're two different strains of the Herpes Simplex Virus

HSV-1 is typically responsible for cold sores and is extremely common. HSV-2 is usually responsible for genital herpes and is far less common.

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Disclaimer: This information isn’t a substitute for professional medical advice, diagnosis, or treatment. You should never rely upon this article for specific medical advice. If you have any questions or concerns, please talk to your doctor.

Have you been diagnosed with herpes? Though there are eight herpes viruses commonly found in humans, you likely have one of two types of the Herpes Simplex Virus (HSV)—HSV-1 or HSV-2, or possibly both. These two viruses have certain distinguishing features and modes of transmission that are important to understand.

What is HSV-1?

Typically, HSV-1 is transmitted orally and causes oral herpes, although in some cases, it can be transmitted sexually and can cause genital herpes. Since it can be passed from person-to-person in multiple ways and can be transmitted even when there are no symptoms present, it is extremely common. 67% of people under the age of 50 worldwide (and 47.8% of Americans aged 14-49) have this strain of the virus (1).

HSV-1 is generally the strain responsible for cold sores on the lips and around the mouth, and occasionally, it can cause sores on other parts of the body, such as the eye or the finger. Most people with the virus never, or rarely, experience outbreaks, which means you may have the virus and have no idea (2).

What is HSV-2?

Whereas HSV-1 is most commonly transmitted orally, HSV-2 is most commonly transmitted sexually and causes genital herpes. Since sexual contact is the primary mode of transmission, it is far less common than HSV-1, but still quite prevalent. 11.9% of people in the U.S. (aged 14-49) have HSV-2 (1).

An outbreak of genital herpes results in ulcers or sores anywhere around the genital region—the groin, the penis or vagina, the buttocks, or the anus. Just like HSV-1, though, you may have HSV-2 and never experience an outbreak (it is estimated that close to 90% of people with the virus never know they have it (3)). The virus can be transmitted even when you are not experiencing an active outbreak, although transmission is more likely during an outbreak.

How Do You Know if You Have HSV-1 or HSV-2?

If you have active lesions, whether around the mouth, the genitals, or any other part of your body, it is important to see your doctor so she or he can run the appropriate tests to determine the cause. There are many other viruses that can cause a variety of skin lesions, and only your doctor will be able to give you a proper clinical diagnosis. Once you have a diagnosis, you have various options for treatment, including directly from your physician or from a Roman-affiliated physician.

Diagnosis is often made clinically, but can be confirmed through testing a sample of an active lesion, or with specific blood tests (4).

Preventing Herpes

For oral herpes, there is little you can do to prevent contracting the virus—as we’ve seen, nearly 50% of the population has it, and can transmit it even without an active outbreak. Simply sharing a water bottle with someone who has the virus can be enough exposure to contract the virus yourself. You can take steps to protect yourself from genital herpes, though, with the use of condoms. If you know you have herpes, taking antivirals, along with condom usage, can greatly reduce your chances of transmitting the virus to others (5).


  1. Prevalence of Herpes Simplex Virus Type 1 and Type 2 in Persons Aged 14–49: United States, 2015–2016. Centers for Disease Control and Prevention. https://www.cdc.gov/nchs/products/databriefs/db304.htm. Published February 7, 2018. Accessed March 17, 2019.
  2. Herpes simplex virus. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/herpes-simplex-virus. Published January 31, 2017. Accessed March 18, 2019.
    Fanfair RN, Zaidi A, Taylor LD, Xu F, Gottlieb S, Markowitz L. Trends in seroprevalence of herpes simplex virus type 2 among non-Hispanic blacks and non-Hispanic whites aged 14 to 49 years–United States, 1988 to 2010. Sex Transm Dis. 2013;40(11):860-864.
  3. STD Facts – Genital Herpes (Detailed version). Centers for Disease Control and Prevention. https://www.cdc.gov/std/herpes/stdfact-herpes-detailed.htm. Published January 31, 2017. Accessed March 17, 2019.
  4. Corey L, Wald A, Patel R, Sacks SL, Tyring SK, Warren T et al. Once-Daily Valacyclovir to Reduce the Risk of Transmission of Genital Herpes | NEJM. New England Journal of Medicine. https://www.nejm.org/doi/full/10.1056/nejmoa035144. Published January 1, 2004. Accessed March 18, 2019.

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