*Shocking headline, I know. But unfortunately, that doesn’t make it any less possible.

According to a new report from the World Health Organization, more than 3.7 billion people under the age of 50 — about 67 percent of the global population — are infected with herpes simplex virus type 1 (HSV-1).

Damn. That’s scary. And half of ’em probably don’t even know.

The Herpes simplex virus is highly contagious and there is still no cure. There is two different types of herpes. The aforementioned HSV-1 is of the mouth. People get blisters around their lips. They’ve been called “cold sores” or fever blisters and is said to primarily be transmitted by oral-to-oral contact.

“Most people contract the virus when they’re kids,” CBS News medical contributor Dr. Holly Phillips said. “It usually lies dormant in the system. It’s incurable. You never get rid of it but it lies dormant most of the time. Every now and again people have outbreaks and that’s when you can see the blisters.”

According to Phillips, there is no one thing that causes an outbreak, because they vary per individual. But stress has been identified as a major trigger.

Read more at EURThisNthat.