Epidemiology: Those living in developing countries are at a higher risk of HSV-1 infection. It has been reported that around a 1/3rd of children living in developing countries are HSV-1 positive by 5 years old and 70-80% of the population are infected by the age of adolescence. In developed countries only 20% of children are infected at the age of 5 and there is no significant increase in disease prevalence until 20–40 years old where the percentage of infected individuals ranges from 40-60%