More than 3.7 billion people under the age of 50—or 67% of the world's population—are infected with herpes simplex virus type 1 (HSV-1), according to World Health Organization's (WHO).
The organization's first global estimates of HSV-1 infection published in the journal PLOS ONE (Oct. 28, 2015). The new estimates highlight that HSV-1 is an important cause of genital herpes. Some 140 million people aged 15 to 49 years are infected with genital HSV-1 infection, primarily in the Americas, Europe, and Western Pacific. Fewer people in high-income countries are becoming infected with HSV-1 as children, likely due to better hygiene and living conditions, and are instead at risk of contracting it genitally through oral sex after they become sexually active.
“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,” said Dr. Marleen Temmerman, director of WHO’s Department of Reproductive Health and Research, in a press release.
Earlier this year, WHO estimated that 417 million people aged 15-49 years have HSV-2 infection, which causes genital herpes. Taken together, the estimates reveal that over half a billion people between the ages of 15 to 49 years have genital infection caused by either HSV-1 or HSV-2 (PLOS ONE Jan. 21, 2015).
“The new estimates highlight the crucial need for countries to improve data collection for both HSV types and sexually transmitted infections in general,” said Dr. Temmerman.
Given the lack of a permanent and curative treatment for both HSV-1 and HSV-2, WHO and partners are working to accelerate development of HSV vaccines and topical microbicides, which will have a crucial role in preventing these infections in the future. Several candidate vaccines and microbicides are currently being studied.
Regional infection estimates
Estimates for HSV-1 prevalence by region among people aged 0-49 in 2012:
Americas: 178 million women (49%), 142 million men (39%)
Africa: 350 million women (87%), 355 million men (87%)
Eastern Mediterranean: 188 million women (75%), 202 million men (75%)
Europe: 207 million women (69%), 187 million men (61%)
South-East Asia: 432 million women (59%), 458 million men (58%)
Western Pacific: 488 million women (74%), 521 million men (73%)
Estimates of new HSV-1 infections among people aged 0-49 in 2012:
Americas: 6 million women, 5 million men
Africa: 17 million women, 18 million men
Eastern Mediterranean: 6 million women, 7 million men
Europe: 5 million women, 5 million men
South-East Asia: 13 million women, 14 million men
Western Pacific: 11 million women, 12 million men