Huge numbers affected by herpes type 1

The herpes simplex virus type 1 is widespread among the global population – affecting two thirds of people under the age of 50, according to a report published yesterday.

The World Health Organisation’s first global estimates of herpes simplex virus type 1 infection indicate that more than 3.7 billion people under the age of 50, that is 67% of the population, are infected with this virus.

Full details are published today (29 October) in the journal PLoS One. The authors explain that there are two forms of the herpes simplex virus – type 1 and type 2. Both are highly infectious and incurable.

Type 1 tends to be transmitted through oral-oral contact and causes cold sores around the mouth, whereas type 2 is usually sexually transmitted through skin-to-skin contact and causes genital herpes.

However, type 1 is also an important cause of genital herpes, affecting about 140 million people aged 15 to 49 years. Rates are higher in the Americas, Europe and Western Pacific, and are reducing among children in high-income countries due to better hygiene and living conditions. Hence the risk increases when they become sexually active.

Recent estimates suggest that infection with type 2 affects 417 million people aged 15 to 49 years. Overall, this means that more than half a billion people between the ages of 15 to 49 years have genital infection caused by either type 1 or type 2.

Dr Marleen Temmerman of the World Health Organisation says: "Access to education and information on both types of herpes and sexually transmitted infections is critical to protect young people’s health before they become sexually active.

"The new estimates highlight the crucial need for countries to improve data collection for both herpes simplex virus types and sexually transmitted infections in general."

World Health Organization HSV-1 estimates. PLoS One 29 October 2015 [abstract]

Looker, K. J. et al. Global Estimates of Prevalent and Incident Herpes Simplex Virus Type 2 Infections in 2012. PLoS One 21 January 2015 doi: 10.1371/journal.pone.0114989 [abstract]