Herpes Simplex Virus

Herpes simplex virus (HSV) causes recurring, blister-like sores, most often around the mouth (oral herpes or cold sores, typically HSV-1) or the genitals (genital herpes, typically HSV-2), though either type can infect either site. HSV is extremely common worldwide, and a large proportion of adults carry HSV-1 antibodies from childhood, usually acquired through non-sexual contact. Once acquired, the virus remains dormant in nerve tissue for life and can reactivate periodically, causing recurrent outbreaks that are usually milder than the first episode. There is no cure, but antiviral treatment controls outbreaks effectively, and many people live full, unaffected lives once they understand how to manage the condition and reduce transmission risk to partners.

Symptoms vary between the first outbreak, which is usually the most severe, and subsequent recurrences. First outbreak: • Painful, fluid-filled blisters that rupture and crust over, typically appearing 2-12 days after exposure • Tingling, itching, or burning sensation in the area before blisters appear (the prodrome) • Pain during urination if sores are near the urethral opening • Flu-like symptoms: fever, body aches, and swollen lymph nodes in the groin or neck Recurrent outbreaks: • Usually shorter and milder than the first episode, often limited to a small cluster of blisters • Frequency varies widely between individuals, from several times a year to rarely at all, and tends to decrease over time Many people carrying HSV never notice symptoms at all, or mistake mild recurrences for other skin irritation, yet can still transmit the virus during periods of asymptomatic viral shedding.

HSV-1 and HSV-2 spread through direct contact with the skin or mucous membranes of an infected person, including kissing, sharing utensils or lip products (HSV-1), and vaginal, anal, or oral sex (HSV-1 or HSV-2). The virus can be transmitted even when no sores are visible, through a process called asymptomatic viral shedding, which is responsible for a significant proportion of new infections. Once it enters the body, the virus travels along nerve fibres to nerve cell clusters near the spine, where it remains dormant and can reactivate later in response to triggers such as stress, illness, sun exposure, menstruation, or a weakened immune system.

• Direct contact with an infected partner during an active outbreak or asymptomatic shedding period • Multiple sexual partners for genital herpes • Weakened immune system, which increases both susceptibility to infection and severity of outbreaks • Existing genital ulcers or breaks in the skin, which ease viral entry • Not using condoms consistently

• Frequent, disruptive recurrences that affect quality of life and relationships • Herpetic keratitis: spread of the virus to the eye, a leading infectious cause of blindness if untreated • Increased risk of acquiring or transmitting HIV, as genital sores provide an entry point for the virus • Neonatal herpes: a rare but serious, potentially life-threatening infection transmitted to a newborn during vaginal delivery if the mother has an active outbreak at that time • Eczema herpeticum: widespread, severe HSV infection in people with pre-existing eczema or other skin barrier conditions

• Avoid direct contact with active sores, including kissing and sexual contact, until fully healed • Use condoms consistently, which reduces but does not eliminate risk since HSV can be transmitted from skin not covered by a condom • Daily suppressive antiviral therapy significantly reduces both outbreak frequency and the risk of transmitting the virus to a partner • Inform sexual partners of your HSV status so they can make informed decisions • Pregnant women with a history of genital herpes should inform their obstetrician, as suppressive therapy late in pregnancy reduces the risk of an outbreak at delivery