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Abstract
Herpes simplex virus (HSV) transmitted from mother to child around the time of delivery can cause potentially fatal disease in the newborn. Women who experience their first genital HSV infection in pregnancy are at the highest risk of transmitting the virus to their newborn. Efforts to prevent vertically transmitted HSV disease can be directed in the following three ways: (i) prevent maternal genital HSV infection; (ii) prevent transmission during pregnancy and delivery; or (iii) postnatally prevent disease in an exposed newborn. Oral aciclovir and valaciclovir given prophylactically in late pregnancy have been shown to limit clinical recurrence of genital herpes, shedding of HSV at delivery and the rate of caesarean delivery for past HSV disease. However, there are insufficient data to determine the effect of oral antiviral prophylaxis in pregnancy on neonatal HSV disease. Neonatal HSV disease should always be treated with systemic antiviral therapy. There is currently no vaccine licensed to prevent genital herpes, although a number show promise in clinical trials. The role of intrapartum antiviral therapy and postnatal strategies to prevent neonatal HSV disease require further evaluation.
1. Herpes Simplex Virus (HSV) Biology and Epidemiology
Herpes simplex virus (HSV) is a ubiquitous pathogen that causes a large burden of disease worldwide, particularly in the immunocompromised and the newborn.[1] There are two HSV serotypes: (i) HSV type 1 (HSV-1), which mainly causes orolabial and CNS infections; and (ii) HSV type 2 (HSV-2), which is the major cause of genital HSV disease. However, both serotypes can cause HSV disease at either end of the body. HSV establishes life-long latency in the sensory ganglia after acute infection, often followed by frequent reactivation and shedding of infectious virus from the site of infection, which is often subclinical. These properties, coupled with the capacity of some HSV proteins to modulate the host's immune response,[2,3] are a major hindrance to the success of public health measures to prevent HSV transmission.
Genital herpes has recently been shown to play a major role in the HIV pandemic, especially in developed countries, where individuals with genital HSV infection display an increased risk of HIV infection after exposure, and an increased rate of HIV transmission to others (including by vertical transmission) once infected.[4,5] Whether HIV-positive women have an increased risk...