HSV-1 vs HSV-2: what the difference means for you

The short version

The CDC describes genital herpes this way: Genital herpes is an STI caused by two types of viruses – herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). The two types are close relatives, and they behave in similar ways. The practical difference is where each one tends to settle and how often it tends to return there.

The table sets them side by side, using only what the WHO and CDC state. Read "usually" into every row, because either type can turn up in either place.

How each one spreads

The WHO fact sheet, dated May 30, 2025, puts HSV-1 this way: Type 1 (HSV-1) mostly spreads by oral contact and causes infections in or around the mouth (oral herpes or cold sores). It can also cause genital herpes. Most adults are infected with HSV-1. The CDC adds that it usually starts early: Most people with oral herpes get it during childhood or young adulthood from non-sexual contact with saliva.

HSV-2 is narrower. The same WHO sheet says: Type 2 (HSV-2) spreads by sexual contact and causes genital herpes. For both types, many people never notice anything: Most people have no symptoms or only mild symptoms. The infection can cause painful blisters or ulcers that can recur over time. Medicines can reduce symptoms but can’t cure the infection.

For kissing specifically, the herpes and kissing guide goes further. For spread when no sore is showing, see the guide to spread without symptoms.

Why HSV-1 can be genital

The shorthand of HSV-1 above the waist and HSV-2 below it doesn't hold up. The CDC explains why: Oral herpes caused by HSV-1 can spread from the mouth to the genitals through oral sex. This is why some cases of genital herpes are due to HSV-1. A partner who gets cold sores can pass HSV-1 to your genitals during oral sex.

So a genital herpes diagnosis doesn't tell you the type on its own. If your result says HSV-1, it is still genital herpes, and it still counts when you talk to a partner. It just tends to come back less often than HSV-2.

How often each comes back

The CDC's patient page says: People who experience an initial outbreak of herpes can have repeated outbreaks, especially if they have HSV-2. However, repeat outbreaks are usually shorter and less severe than the first outbreak. Its clinical treatment guidelines, last reviewed September 21, 2022, are more specific about HSV-1: Recurrences are less frequent after the first episode of HSV-1 genital herpes, compared with genital HSV-2 genital herpes, and genital shedding rapidly decreases during the first year of infection

Shedding is the virus appearing on the skin, which is how it passes when you have no sore. That line from the guidelines matters for a partner as much as for you. None of the sources quoted here gives a rate for how much less often, so this page doesn't give one either.

For both types, the long view looks similar. In the CDC's words, Although genital herpes is a lifelong infection, the number of outbreaks may decrease over time. and the WHO puts it this way: People can have repeated outbreaks over time (‘recurrences’). These are usually shorter and less severe than the first outbreak. The guide to whether herpes gets less contagious covers how that plays out over the years.

How common each is

HSV-1 is the more common of the two by a wide margin. The WHO fact sheet, dated May 30, 2025, estimates 64% of people under 50 worldwide have HSV-1. For HSV-2, it estimates 13% of people aged 15 to 49 had it in 2020.

In the United States, the National Center for Health Statistics measured both types in 2015 to 2016. Among people aged 14 to 49, 47.8% had HSV-1 and 11.9% had HSV-2. The CDC guidelines use the same HSV-2 figure: 11.9% of persons aged 14–49 years are estimated to be infected in the United States If you have either type, you're in large company.

What the type changes for dating

The type doesn't decide whether you tell a partner. Genital herpes is genital herpes, and a partner deserves to know before sex either way. If your HSV-1 is oral (cold sores), the kissing guide covers that conversation instead. What the type changes is what you tell them, and what they are weighing when they hear it.

If you have genital HSV-1, you can say so and share what the CDC says about fewer recurrences and shedding that drops in the first year. If you have HSV-2, you can say that repeat outbreaks usually get shorter and milder, and that the number may decrease over time. Name the type either way, so a partner can read the same CDC pages you did.

A partner may already carry one of the types without knowing it. That doesn't make the conversation optional, but it can make it less lopsided. If you both turn out to have herpes, the guide for couples who both have it covers what changes.

For timing and wording, the first disclosure guide walks through the talk, and the script builder helps you draft it with your type included. The transmission guide has the numbers on lowering the risk to a partner. You can't decide how someone reacts, but you can decide to say it clearly, before sex.

Finding out your type

If you don't know your type, ask. Not every herpes blood test tells the two apart, and the CDC guidelines are specific about it: Type-common antibody tests do not distinguish between HSV-1 and HSV-2 infection; therefore, type-specific serologic assays should be requested So ask for a type-specific blood test by name.

Blood tests have limits, including timing and wrong results, so have a clinician read yours. The herpes test guide covers which test to ask for, when, and what the result means.