Two-thirds of the people in the world who are under age 50 are infected with the herpes virus that causes cold sores or fever blisters around the mouth, the World Health Organization said. In North and South America, it is estimated that almost half of women have oral herpes. This is the first time that WHO has estimated the global prevalence of herpes infections.
More than 3.7 billion people under the age of 50 are infected with herpes simplex virus type 1 (HSV-1), the cold sore kind, usually after catching it in childhood, according to the WHO study. An additional 417 million people aged 15 to 49 have the other form of the disease, HSV-2, which causes genital herpes. "Taken together, the estimates reveal that over half a billion people between the ages of 15-49 years have genital infection caused by either HSV-1 or HSV-2," the organization said in a statement.
However, HSV-1 is becoming an increasing cause of genital infection too, mainly in rich countries. Improved hygiene in rich countries is lowering HSV-1 infection rates in childhood, which leaves people at greater risk of catching it via oral sex when they become sexually active.
Being infected with HSV-2 can increase a person's risk of catching and spreading HIV, the virus that causes AIDS. But little is known if there is any link between HSV-1 and HIV/AIDS.
Herpes is a lifelong infection, which often has mild or no symptoms but can be detected by the presence of antibodies for HSV-1 or HSV-2 in the blood. The virus can lead to serious complications such as encephalitis or herpes infections of the eye. It is difficult to determine the proportion of HSV-infected people worldwide who have symptomatic disease, as symptoms may be mild or simply not recognized as herpes.
WHO is working with several pharmaceutical firms to create vaccines against herpes viruses.
