Herpes simplex virus 1 and 2 are two members of the human Herpesviridae family, a set of viruses that produce viral infections in the majority of humans. Both HSV-1 and HSV-2 are very common and contagious. They can be spread when an infected person begins shedding the virus.
As of 2016, about 67% of the world population under the age of 50 had HSV-1.
