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Herpes is one of the world’s most common sexually transmitted infections (STI). An estimated 12% of Americans aged 14 to 49 years are infected with the virus that predominantly causes genital herpes, and these numbers might even be higher depending on what herpes virus you look at (McQuillan, 2018). With numbers like that, you may wonder if it’s possible to have herpes and not know it. Unfortunately, it is possible, and asymptomatic herpes is one way this infection spreads so easily. In fact, the Centers for Disease Control and Prevention (CDC) say most people with genital herpes infection do not know they have it.
What is asymptomatic herpes?
Asymptomatic herpes describes a herpes infection that does not come with any symptoms. Common symptoms of herpes include (Mathew, Jr., 2021; Saleh, 2021):
- Itching, burning, or tingling around the mouth, lips, or genital area
- Blisters or cold sores that may develop into pus-filled lesions
- Pain while urinating
The symptoms of herpes are typically worse during the initial outbreak, which can last for two to six weeks. Subsequent herpes outbreaks are usually milder (Mathew, Jr., 2021; Saleh, 2021). While some people first experience symptoms fairly quickly, within hours to days after exposure, it may take longer for symptoms to develop (Saleh, 2021; Groves, 2016).
But, many herpes infections are asymptomatic, meaning many people contract herpes and don’t experience any of these symptoms or have mild symptoms that go unrecognized (Feltner, 2016; Shannon, 2014).
What causes herpes?
There are many different types of herpes viruses, but when you hear “herpes,” you’re likely thinking of two types of the herpes simplex virus: herpes simplex virus type 2 (HSV-2) and herpes simplex virus type 1 (HSV-1), two viruses that can cause sores on your genitals and mouth.
HSV-2 infections typically cause genital herpes, while HSV-1 infections typically cause oral herpes, also known as cold sores. However, either virus can cause either type of herpes. Once you have HSV-1 or HSV-2, you’ll have it for life. Most of the time, you won’t have any symptoms, but from time to time, you can have outbreaks. HSV-2 outbreaks tend to occur more frequently, while HSV-1 outbreaks are milder (Groves, 2016).
Can you have herpes and not know it?
Yes, you can have herpes and not know it. Most people with genital herpes do not experience symptoms and may not know they have herpes. It’s also possible to have oral herpes and not know it. Many people get oral herpes in childhood and have fewer symptomatic outbreaks, if any, so they may never know they have it. Almost half of Americans aged 14 to 49 are infected with HSV-1 (Shannon, 2014; Feltner, 2016; McQuillan, 2018).
Genital herpes: signs, symptoms, treatment, and more
Experts estimate around 65% to 90% of people with genital herpes are unaware that they have it (Groves, 2016).
However, people with asymptomatic herpes can still pass herpes to other people. In fact, most infections pass asymptomatically (Schiffer, 2014). Herpes can be transmitted through saliva, kissing, oral sex, or genital-to-genital contact with an infected person, whether or not that person has a noticeable outbreak. A small number of pregnant women pass it on to their child, known as neonatal herpes (Saleh, 2021; Groves, 2016).
Is asymptomatic herpes less contagious?
While it’s true that the risk of spreading herpes is greater when a person has signs of active infection, it is still contagious even without symptoms. People with an asymptomatic herpes infection shed the virus about half as often as people with symptomatic herpes (Tronstein, 2011).
What are the chances of getting herpes from an asymptomatic partner?
It’s hard to nail it down to an exact number, because the risk of getting herpes hinges on a couple of things. As with other STIs, your chances of getting herpes go up according to how often you have sex, the number of sex partners you have, and how often condoms are used. Besides that, women are at a greater risk of contracting herpes than men (Groves, 2016).
But there are some estimates about the likelihood of an asymptomatic person shedding the virus. According to one study, people with asymptomatic herpes shed the virus 10% of the days they were in the study, about half as often as those with symptomatic herpes (Tronstein, 2011). However, other studies have found that asymptomatic shedding can be as high as 20%. Herpes viral shedding may occur more often during the first year of infection (Groves, 2016).
Oral antiviral medications for herpes include valacyclovir (Valtrex; see Important Safety Information), acyclovir, and famciclovir.
Herpes is not curable, but medication can reduce your risk of experiencing an outbreak, as well as lower the risk of transmitting it to others. These medications can be used to shorten an episode when taken at the first sign or symptom of an outbreak. Or they can be used on an ongoing basis. For example, taking acyclovir on a long-term basis, also known as suppressive therapy, can prevent up to 80% of outbreaks and reduce shedding by over 90%. Using condoms and sharing your status with your sexual partners can also reduce the risk of transmission (Tronstein, 2011; Mathew, Jr., 2021).
How you can get genital herpes on your mouth and vice versa
How do you know if you have herpes?
If you think you may have herpes, the best way to find out is by taking a blood test that looks for the presence of antibodies or the virus itself. The viral test can also identify whether you have an HSV-1 or HSV-2 herpes infection (Saleh, 2021; Feltner, 2016). It can take a couple of weeks for HSV antibodies to form and be detectable, so you may want to wait at least that long after an exposure to get the most accurate results or take a second test to be sure (Groves, 2016).
If you think you have herpes, either because you were exposed or have symptoms, contact your healthcare provider and avoid sexual contact with others or practice safe sex to prevent spreading the infection (Mathew, Jr., 2021).
People with asymptomatic herpes can still pass herpes on to others, just as those who experience outbreaks can.
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- Feltner, C., Grodensky, C., Ebel, C., et al. (2016). Serologic screening for genital herpes: An updated evidence report and systematic review for the US Preventive Services Task Force. JAMA, 316(23), 2531–2543. doi:10.1001/jama.2016.17138. Retrieved from https://pubmed.ncbi.nlm.nih.gov/27997660/
- Groves, M. J. (2016). Genital herpes: A review. American Family Physician, 93(11), 928–934. Retrieved from https://pubmed.ncbi.nlm.nih.gov/27281837/
- Mathew, Jr., J. & Sapra, A. (2021). Herpes simplex type 2. StatPearls. Retrieved on Jun. 7, 2022 from https://www.ncbi.nlm.nih.gov/books/NBK554427/
- McQuillan, G. (2018). Prevalence of herpes simplex virus type 1 and type 2 in persons aged 14–49: United States, 2015–2016. NCHS Data Brief, no 304. Retrieved from https://www.cdc.gov/nchs/data/databriefs/db304.pdf
- Saleh, D., Yarrarapu, S. N. S., & Sharma, S. (2021). Herpes simplex type 1. StatPearls. Retrieved on Jun. 7, 2022 from https://www.ncbi.nlm.nih.gov/books/NBK482197/
- Schiffer, J. T., Mayer, B. T., Fong, Y., et al. (2014). Herpes simplex virus-2 transmission probability estimates based on quantity of viral shedding. Journal of the Royal Society, Interface, 11(95), 20140160. doi:10.1098/rsif.2014.0160. Retrieved from https://pubmed.ncbi.nlm.nih.gov/24671939/
- Shannon, B., Yi, T. J., Thomas-Pavanel, J., et al. (2014). Impact of asymptomatic herpes simplex virus type 2 infection on mucosal homing and immune cell subsets in the blood and female genital tract. Journal of Immunology, 192(11), 5074–5082. doi:10.4049/jimmunol.1302916. Retrieved from https://pubmed.ncbi.nlm.nih.gov/24760150/
- Tronstein, E., Johnston, C., Huang, M. L., et al. (2011). Genital shedding of herpes simplex virus among symptomatic and asymptomatic persons with HSV-2 infection. JAMA, 305(14), 1441–1449. doi:10.1001/jama.2011.420. Retrieved from https://pubmed.ncbi.nlm.nih.gov/21486977/
Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.