Neonatal herpes: Frequently Asked Questions

What is Herpes Simplex Virus (HSV)?
Herpes simplex virus is a common virus which spreads from person to person by direct contact. In adults it can cause different symptoms depending on the site of infection and the type of virus (HSV type 1 or HSV type 2). Some people can have no symptoms of infection and in others it can lead to cold sores, blisters of the mouth/throat, genital ulcers/sores or infections of the brain, eye or skin. Once you get HSV infection, the virus remains in the body for life and may reactivate from time to time. The first infection is usually the most severe and lasts the longest. Recurrent infections are usually less severe and improve quickly.

In babies infection with HSV is rare but can have devastating consequences as their immune system is not fully developed to fight off the virus.

HSV infection in babies is typically divided into three subgroups depending on the site of infection.

  • Infection of the Skin, Eye and/or Mouth (SEM Disease)
  • Infection involving the brain (Central Nervous System (CNS) infection)
  • Infection involving multiple organs such as the lungs, liver, brain (disseminated infection)

How do babies get infected?
Babies can become infected with HSV in the womb (~5%) around the time of birth through contact with HSV infected sections in the birth canal (~85%) or contact with the virus in the days after birth (10%). Many factors influence the risk of the baby getting an infection but the risk is greatest when HSV infection is acquired for the first time by the mother in pregnancy and particularly when the infection occurs in the third trimester close to the time of birth.

The virus can also be passed on to a newborn baby from caregivers, or those in close contact with a newborn who have HSV skin problems such as cold sores, HSV infected broken skin (eczema herpeticum) or blisters on the fingers due to HSV (herpetic whitlows).

What are the signs of infection?
Babies with HSV can become unwell very quickly, and the symptoms may not be very obvious. Signs of infection in babies include:

  • Lethargy or irritability
  • Not feeding
  • High temperature
  • Grunting or difficulty with breathing
  • Rash or sores on the skin, eye or inside the mouth

If you are concerned that your baby may have an infection, seek medical advice as soon as possible.

Can neonatal HSV be treated?
An antiviral medication (Aciclovir) is used for the treatment of HSV. The medication is given into the bloodstream (intravenously) for several weeks. Some babies, particularly those with SEM disease, will make a full recovery with treatment but the condition is much more serious if it has spread to the baby’s organs and may result in death even with treatment.

How can the risk of neonatal HSV be reduced?
If you are pregnant it is important to inform your doctor/midwife

  • If you have ever had genital herpes (ulcers/painful blisters/sores) in the past
  • If you develop genital herpes (ulcers/painful blisters/sores) during your pregnancy

Your doctor can then advise on ways to reduce the risk of passing on the infection which may include prescribing antiviral medication and discussion about the type of delivery. In some circumstances particularly where infection occurs for the first time close to the time of birth a Caesarean section may be recommended.

HSV infection can also occur from contact with HSV skin lesions such as cold sores, herpetic whitlow or infected broken skin. It is important that anybody who has contact with a newborn infant is aware of the risk of Neonatal HSV and takes appropriate precautions such as the following:

  • Wash hands before contact with a baby
  • Cover the cold sore or skin lesion if possible.
  • Do not kiss the baby
  • If blisters are present on the breast, seek medical advice before breastfeeding

Healthcare workers who are in contact with newborn babies should be aware of the risk of HSV transmission and seek advice from occupational health if they have signs or symptoms of HSV oral/skin lesions.

For further information 

Last updated: 28 January 2019