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HSV-1 vs. HSV-2: what’s the difference?

Mike Bohl, MD, MPH, ALM

Reviewed by Mike Bohl, MD, MPH, ALM, written by Rachel Honeyman

Last updated: Apr 29, 2021
2 min read


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.

Have you been diagnosed with herpes? Though there are eight types of herpes viruses commonly found in humans, when you hear “herpes,” you’re likely thinking of either herpes simplex virus type 1 (HSV-1) or herpes simplex virus type 2 (HSV-2). These two viruses have certain distinguishing features and modes of transmission that are important to understand.


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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. 47.8% of Americans aged 14–49 have this strain of the virus (CDC, 2018).

HSV-1 is generally the strain responsible for cold sores on the lips and around the mouth. 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 (WHO, 2017).

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 less common than HSV-1, but still quite prevalent. 11.9% of people in the U.S. aged 14–49 have HSV-2 (CDC, 2017).

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. 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 healthcare provider to undergo appropriate testing to determine the cause. Diagnosis is sometimes made clinically (based on your history and physical exam) but can be confirmed through testing a sample of an active lesion. Blood tests can also tell if you have either of the viruses. Once you have a diagnosis, you have various options for treatment.

Preventing herpes

For oral herpes, it may be hard to prevent contracting the virus—as we’ve seen, nearly 50% of the population has it. Simply sharing a water bottle with someone who has the virus can be enough exposure to contract the virus yourself—although this is rare if they do not have an active outbreak. You can reduce your risk of genital herpes, though, by practicing safe sex—although this isn’t 100% effective. If you know you have herpes, taking antivirals, along with condom usage, can greatly reduce your chances of transmitting the virus to others.


  1. Centers for Disease Control and Prevention. (2018, February 7). Products – Data Briefs – Number 304 – February 2018. Retrieved April 29, 2020 from
  2. Centers for Disease Control and Prevention. (2017, January 31). STD Facts – Genital Herpes (Detailed version). Retrieved April 29, 2020 from
  3. World Health Organization. (2017, January 31). Herpes simplex virus. Retrieved April 29, 2020 from 

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