The herpes simplex virus is one of the world’s most common viruses, affecting more than half of all people aged 14 to 49 (in its HSV-1 form) and around 11% of people worldwide (as HSV-2). Herpes can affect the lips, face and mouth (oral herpes) or the genitals, upper legs and buttocks (genital herpes). Most of the time, oral herpes is caused by the HSV-1 type of the virus, with the majority of genital herpes cases caused by the HSV-2 strain of the herpes virus.However, this isn’t always the case. HSV-1, which is the most common form of herpes and the form of the virus most commonly spread through oral-to-oral contact like kissing, can spread to the genitals through oral sex. In short, you can get herpes from oral sex, particularly if the person giving oral sex has an active outbreak of oral herpes.
Below, we’ll explain how oral-to-genital herpes transmission occurs. We’ll also cover the key risk factors you should be aware of, as well as the best ways to reduce your risk of catching genital herpes through sexual contact.
Herpes is an infectious virus that spreads primarily through skin-to-skin contact. Most transmissions of herpes involve oral-to-oral contact such as kissing. When a person with HSV-1 kisses someone without HSV-1, the virus can spread into the other person’s mouth through the infected person’s saliva.
During an outbreak of oral herpes, an infected person will start to develop cold sores. The risk of transmission is highest during an actual outbreak, as the infected person is actively “shedding” the virus through cold sores that contain infectious fluid.
Because of this, if you’re concerned about HSV-1, it’s best not to kiss someone if they have a visible cold sore. Our guide to kissing and herpes goes into more detail about how oral herpes can spread through simple oral-to-oral contact with an infected person. If you have a cold sore, you should avoid kissing anyone until the sore has completely healed and your skin has recovered.
It’s also important to know that herpes can spread from one person to another even if someone doesn’t have any visible symptoms. In fact, the majority of herpes infections are asymptomatic, meaning many people spread the virus without ever realizing they’re infected.
Contrary to popular belief, herpes can also spread from the mouth to the genitals. For example, if you have a cold sore and perform oral sex on your partner, there’s a risk of the virus infecting the other person via viral shedding—the same process that causes oral herpes to spread.
The most common causes of HSV-1 spreading to the genitals are oral sex acts such as fellatio, cunnilingus and analingus. Both men and women can contract genital herpes through contact with a partner infected with oral herpes.
It’s important to know that you do not need to have HSV-2 to spread genital herpes. Most cases of genital herpes are caused by the HSV-2 strain of the virus, but HSV-1 can and does spread from the mouth to the genitals.
Like with oral herpes transmission, oral-to-genital herpes transmission can occur even if the person infected with the virus doesn’t have any visible symptoms.
If you’re aware that you have HSV-1, there are several steps that you can take to reduce your risk of transmitting it to your sexual partner as genital herpes:
Our guide to having sex when you have herpes goes into more detail about how you can further reduce your transmission risk and maintain a normal sex life after learning that you have HSV-1 or HSV-2. If you're infected with the virus or think you might be, it's always best to speak to your doctor about your options and testing. Odds are, they'll prescribe an antiviral medication like valacyclovir, which makes HSV-1 and HSV-2 extremely simple to manage.