One theory of how the herpes virus evolved to cause facial herpes is based on the emergence of the practice of kissing. — AFP
The modern strain of the virus that causes cold sores has been traced back to around 5,000 years ago, with researchers suggesting its spread could have been propelled by the emergence of kissing.
Around 3.7 billion people – the majority of the world's population – have a life-long infection of the herpes simplex virus 1 (HSV-1) behind facial herpes, according to the World Health Organization (WHO).
