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Istituto Superiore di Sanità
EpiCentro - Epidemiology for public health
Epidemiology for public health - ISS

Genital herpes is an infection caused by the herpes simplex virus (HSV), of which there are two types: type 1 (HSV-1) and type 2 (HSV-2). HSV is very common worldwide, and over 500 million people are estimated to have an infection with HSV. The virus usually lies dormant within its host for life, but may be reactivated if the infected person’s immune system becomes weaker (for example, as a result of mental and physical stress, local tissue trauma, UV radiations, fever, menstruation, immunosuppression).


HSV-2 primarily causes genital herpes, which is the most common sexually-transmitted ulcerative disease worldwide and a global health problem.


HSV-1 is primarily responsible for oral herpes. In the last few years, however, an increasing proportion of genital herpes infections have been attributed to this subtype. Neonatal infection with HSV-2 is possible: 85% of infants acquire the infection during delivery, 10% after birth (e.g. through breastfeeding, if the mother has herpes lesions on her breast, or kisses) and the remaining 5% by intrauterine exposure. Complications for the baby include disseminated infections affecting several organs (lungs, liver, skin, brain, eyes), central nervous system infections (encephalitis) and localized infections of the skin, eyes and mouth.


HSV-2 infection increases the risk of contracting or spreading HIV and is one of the most common infections among people with HIV.


Publication date: 15 January 2021