What is the percentage of passing herpes without an outbreaks

Overview

Infection with herpes simplex virus (HSV), known as herpes, is common globally. HSV type 1 (HSV-1) is typically transmitted by oral-to-oral contact and causes infection in or around the mouth (oral herpes), but it can also cause genital herpes. HSV-2 is mainly sexually transmitted and causes genital herpes.

Both oral and genital herpes are mostly asymptomatic or unrecognized but can cause painful blisters or ulcers at the site of infection, ranging from mild to severe. Infection is lifelong, and symptoms can recur over many years. Some medications are available to reduce the severity and frequency of symptoms, but they cannot cure the infection.

Recurrent symptoms of both oral and genital herpes may be distressing. Genital herpes can also be stigmatizing and have an impact on sexual relationships. However, in time, most people with either kind of herpes adjust to living with the infection.

Scope of the problem

In 2016 (last available estimates), 3.7 billion people under the age of 50, or 67% of the population, had HSV-1 infection (oral or genital). Most HSV-1 infections are acquired during childhood.

Genital herpes caused by HSV-2 affects an estimated 491 million (13%) people aged 15–49 years worldwide (2016 data). HSV-2 infects women almost twice as often as men because sexual transmission is more efficient from men to women. Prevalence increases with age, though the highest number of new infections are in adolescents.

Signs and symptoms

Oral herpes infection is mostly asymptomatic, but symptoms can include painful blisters or open sores (ulcers) in or around the mouth (cold sores). Infected persons will often experience a tingling, itching or burning sensation around their mouth before the appearance of sores. These symptoms can recur periodically, and the frequency varies from person to person.

Genital herpes can be asymptomatic or have mild symptoms that go unrecognized. When symptoms occur, genital herpes is characterised by one or more genital or anal blisters or ulcers. Additionally, symptoms of a new infection often include fever, body aches and swollen lymph nodes. After an initial episode, which can be severe, symptoms may recur. Genital herpes caused by HSV-1 typically does not recur frequently. With HSV-2, recurrent symptoms are common. However, recurrences are often less severe than the first episode and tend to decrease over time.

Transmission

HSV-1 is mainly transmitted via contact with the virus in sores, saliva or surfaces in or around the mouth. Less commonly, HSV-1 can be transmitted to the genital area through oral-genital contact to cause genital herpes. It can be transmitted from oral or skin surfaces that appear normal; however, the greatest risk of transmission is when there are active sores. People who already have HSV-1 are not at risk of reinfection, but they are still at risk of acquiring HSV-2.

HSV-2 is mainly transmitted during sex through contact with genital or anal surfaces, skin, sores or fluids of someone infected with the virus. HSV-2 can be transmitted even if the skin looks normal and is often transmitted in the absence of symptoms.

In rare circumstances, herpes (HSV-1 and HSV-2) can be transmitted from mother to child during delivery, causing neonatal herpes.

Possible complications

HSV-2 and HIV infection

HSV-2 infection increases the risk of acquiring HIV infection by approximately three-fold. Additionally, people with both HIV and HSV-2 infection are more likely to spread HIV to others. HSV-2 infection is among the most common infections in people living with HIV.

Severe disease

In immunocompromised people, including those with advanced HIV infection, herpes can have more severe symptoms and more frequent recurrences. Rare complications of HSV-2 include meningoencephalitis (brain infection) and disseminated infection. Rarely, HSV-1 infection can lead to more severe complications such as encephalitis (brain infection) or keratitis (eye infection).

Neonatal herpes

Neonatal herpes can occur when an infant is exposed to HSV during delivery. Neonatal herpes is rare, occurring in an estimated 10 out of every 100 000 births globally. However, it is a serious condition that can lead to lasting neurologic disability or death. The risk for neonatal herpes is greatest when a mother acquires HSV for the first time in late pregnancy.

Treatment

Antiviral medications – such as acyclovir, famciclovir and valacyclovir – are the most effective medications for people infected with HSV (see WHO recommendations). These can help to reduce the severity and frequency of symptoms but cannot cure the infection.

Prevention

People with symptoms of oral herpes should avoid oral contact with others (including oral sex) and sharing objects that touched saliva. Individuals with symptoms of genital herpes should abstain from sexual activity while experiencing symptoms. Both HSV-1 and HSV-2 are most contagious when sores are present, but can also be transmitted when no symptoms are felt or visible.

For sexually active people, consistent and correct use of condoms is the best way to prevent genital herpes and other STIs. However, HSV infection can still occur through contact with genital or anal areas not covered by the condom. Medical male circumcision can provide life-long partial protection against HSV-2 infection, as well as against HIV and human papillomavirus (HPV).

People with symptoms suggestive of genital herpes should be offered HIV testing.

Pregnant women with symptoms of genital herpes should inform their health care providers. Preventing acquisition of HSV-2 infection is particularly important for women in late pregnancy when the risk for neonatal herpes is greatest.

WHO response

WHO is working to increase awareness about HSV infection and its symptoms, improve access to antiviral medications, and promote HIV prevention efforts for those with genital herpes, such as pre-exposure prophylaxis (PrEP). 

WHO and partners are also supporting research to develop new strategies for prevention and control of HSV infections, such as vaccines and topical microbicides.

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