Approximately two-thirds of all people under age 50 across the globe are infected with herpes simplex virus type 1 (HSV-1), the virus most commonly associated with cold sores, according to a World Health Organization (WHO) report released today in the journal PLOS One.
That’s 3.7 billion people worldwide.
The burden of infection varies in different parts of the world and between men and women, according to the report. In the Americas, about 39% of all women are infected and 49% of men. In the Eastern Mediterranean, 75% of both men and women are infected and 87% of both men and women are infected in Africa.
And that’s just men and women under age 50. Above this age, the burden of infection would probably “trend toward 100%” in many places, says Bryan Cullen, director of the Duke University Center for Virology, although the WHO study doesn’t include these statistics.
HSV-1 is the same virus most commonly responsible for causing skin lesions, or “cold sores,” around the mouth, a disease than can be transmitted via skin-to-skin contact, such as kissing. But while cold sores are a mostly cosmetic issue, there’s good reason to collect data on the virus, argue some experts.