5 May 2020
About half a billion people worldwide are living with genital herpes, and several billion have an oral herpes infection, new estimates show, highlighting the need to improve awareness and scale up services to prevent and treat herpes.
The research, led by Dr Katharine Looker from the NIHR Health Protection Research Unit in Behavioural Science and Evaluation at University of Bristol in collaboration with the World Health Organization (WHO), and Weill Cornell Medical College-Qatar, found that about 13% of the world’s population aged 15 to 49 years were living with herpes simplex virus type 2 (HSV-2) infection in 2016, the latest year for which data is available.
HSV-2 is almost exclusively sexually transmitted, causing genital herpes. Infection can lead to recurring, often painful, genital sores in up to a third of people infected.
Herpes simplex virus type 1 (HSV-1) is mainly transmitted by oral to oral contact to cause oral herpes infection – sometimes leading to painful sores in or around the mouth (cold sores). However, HSV-1 can also be transmitted to the genital area through oral sex, causing genital herpes.
Around 67% of the world’s population aged 0 to 49 had HSV-1 infection in 2016 – an estimated 3.7 billion people. Most of these infections were oral; however, between 122 million to 192 million people were estimated to have genital HSV-2 infection.
Dr Looker, Senior Research Associate in Mathematical Epidemiology of Infectious Diseases at the University of Bristol, said: "Our estimates show that herpes infection affects billions of people worldwide, whether oral infection which may cause cold sores, or genital infection causing genital herpes. Although many people do not have recognized symptoms, the global disease burden associated with herpes will be huge, since infection is so common. Unfortunately, current methods of preventing infection are inadequate, and access to treatment is limited in many countries. Addressing these issues would have a substantial impact on global health."
Dr Ian Askew, Director of the Department of Sexual and Reproductive Health and Research at the World Health Organization (WHO), said: "Genital herpes is a substantial health concern worldwide – beyond the potential pain and discomfort suffered by people living with the infection, the associated social consequences can have a profound effect on sexual and reproductive health."
Herpes and HIV
People with HSV-2 infection are at least three times more likely to become infected with HIV, if exposed. Thus, HSV-2 likely plays a substantial role in the spread of HIV globally. Women are more susceptible to both HSV-2 and HIV. Women living in the WHO Africa Region have the highest HSV-2 prevalence and exposure to HIV – putting them at greatest risk of HIV infection.
No cure: vaccine needed
There is no cure for herpes. Antiviral medications, such as acyclovir, famciclovir, and valacyclovir, can help to reduce the severity and frequency of symptoms but cannot cure the infection.
Better awareness, improved access to antiviral medications and heightened HIV prevention efforts for those with genital HSV symptoms are needed globally. In addition, development of better treatment and prevention interventions is needed, particularly HSV vaccines.
Dr Meg Doherty, Director of the WHO Department of Global HIV, Hepatitis, and STI Programmes, said: “A vaccine against HSV infection would not only help to promote and protect the health and well-being of millions of people, particularly women, worldwide – it could also potentially have an impact on slowing the spread of HIV, if developed and provided alongside other HIV prevention strategies."
Herpes simplex virus: global infection prevalence and incidence estimates, 2016. Charlotte James, Manale Harfouche, Nicky J Welton, Katherine ME Turner, Laith J Abu-Raddad, Sami L Gottlieb & Katharine J Looker. Published in Bulletin of the World Health Organization. May 2020.
The global and regional burden of genital ulcer disease due to herpes simplex virus: a natural history modelling study. Katharine Jane Looker, Christine Johnston, Nicky J Welton, Charlotte James, Peter Vickerman, Katherine M E Turner, Marie-Claude Boily, Sami L Gottlieb. Published in BMJ Global Health. March 2020.
Global and regional estimates of the contribution of herpes simplex virus type 2 infection to HIV incidence: a population attributable fraction analysis using published epidemiological data. Katharine J Looker, Nicky J Welton, Keith M Sabin, Shona Dalal, Peter Vickerman, Katherine M E Turner, Marie-Claude Boily, Sami L Gottlieb. Published in The Lancet Infectious Diseases. November 2019.
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