If you’re reading this, you probably just learned that cold sores are caused by herpes, and you’re having a moment. Take a breath. About half of all Americans have the same virus. Let’s talk about what this actually means.
Yes, cold sores are herpes
Cold sores (also called fever blisters) are caused by herpes simplex virus type 1 (HSV-1). That’s the same family of virus that causes genital herpes (typically HSV-2, though HSV-1 can cause genital infections too). The word “herpes” just means it’s caused by the herpes simplex virus.
The reason most people don’t know this is simple: nobody calls cold sores “herpes.” Your aunt calls it a cold sore. Your doctor calls it a fever blister. The pharmacy sells “cold sore cream.” The word “herpes” has been quietly edited out of the conversation for decades, and that editing is a big part of why the stigma exists in the first place.
How common is it?
Extremely. According to the World Health Organization, an estimated 3.8 billion people under age 50 carry HSV-1 worldwide. In the U.S., about 48% of Americans ages 14–49 have oral HSV-1, according to CDC data.
Most people get it as children, from a kiss from a parent, sharing a cup, or just being a kid. It’s so common that many doctors don’t even consider it worth mentioning. Which, again, tells you something about the gap between the medical reality and the stigma.
Cold sores vs. genital herpes: same virus, different location
Here’s where it gets interesting. HSV-1 and HSV-2 are two strains of the same virus. The main difference is where they prefer to hang out:
- HSV-1 prefers the oral area (cold sores) but can infect the genitals
- HSV-2 prefers the genital area but can infect the mouth (though this is rare)
Both types cause the same kind of sores. Both follow the same pattern: an initial outbreak, a dormant period where the virus lives in nerve ganglia, and possible recurrences. Both respond to the same antiviral medications. For a deeper dive into how the two types compare, see our complete guide to HSV-1 vs. HSV-2.
Can cold sores cause genital herpes?
Yes. This is the part most people don’t realize. If someone with oral HSV-1 performs oral sex on a partner, the virus can be transmitted to the genitals. HSV-1 is now the leading cause of new genital herpes cases in young adults, accounting for 30–50% of all genital herpes infections.
This can happen even when no cold sore is visible. HSV-1 can shed asymptomatically from the mouth on roughly 9–25% of days, meaning the virus can be present on the skin surface without any symptoms.
That’s not meant to scare you, it’s meant to inform you. The actual transmission rates per encounter are low. But it’s worth knowing, especially if you or a partner get cold sores.
Why nobody panics about cold sores
Think about this: if you told a friend “I get cold sores,” they’d probably shrug. Maybe say “oh yeah, me too.” If you told that same friend “I have herpes,” the reaction would be completely different, even though you’re describing the same virus.
That gap (between the casual shrug and the panic) is pure stigma. It’s not based on medical severity, transmission risk, or health outcomes. It’s based on where the virus shows up and whether we use the word “herpes” or not.
Cold sores got a pass because they’re on the face, they’re common in families, and the word “herpes” was swapped out for friendlier language decades ago. Genital herpes got the stigma because it’s associated with sex. Same virus. Completely different social response. That tells you everything you need to know about what the stigma is actually about.
What if you just found out your cold sores are herpes?
If you’re having a bit of a moment right now, that’s okay. A lot of people feel weird when they first connect the dots. Here’s what to keep in perspective:
- Nothing about your health changed. You had cold sores yesterday, you have cold sores today. The only thing that changed is the label.
- You’re in extremely common company. Nearly half of all Americans carry HSV-1. Globally, it’s 3.8 billion people.
- Cold sores are manageable. Antiviral medication (like valacyclovir) can shorten outbreaks or prevent them. Many people take it at the first tingle and the sore never fully develops.
- You probably already know plenty of people who have it. They just call it a cold sore.
Do you need to disclose cold sores?
This is a personal call. There’s no legal requirement to tell someone you get cold sores before kissing them. But if you know you carry HSV-1, a casual mention (“Hey, just FYI, I get cold sores sometimes”) is a small act of respect that most people appreciate. We wrote a whole piece on whether and how to disclose cold sores if you want to go deeper on this.
The bigger conversation is about oral sex. Since oral HSV-1 can be transmitted to a partner’s genitals, it’s worth being aware of the transmission risks and having an honest conversation. Not because it’s scary, but because honesty builds trust, and that’s what real connection looks like.
The bottom line
Cold sores are herpes. That’s a medical fact, not a judgment. The virus that causes cold sores (HSV-1) is carried by roughly half the world’s population, most of whom got it as kids. It’s the same virus that can cause genital herpes. The only reason one version comes with stigma and the other doesn’t is language and location, not medical reality.
If learning this changes how you think about herpes stigma, good. That’s the point. The more people understand that cold sores are herpes, the harder it becomes to treat genital herpes like it’s something to be ashamed of. It was never something to be ashamed of. And now that you know the facts, you can let go of a little bit of that fear. You've got this. :)
