top of page
Neonatal Herpes Information and Advice
Neonatal herpes information and advice

Neonatal herpes simplex virus (HSV) disease, also called 'neonatal herpes' or 'neonatal HSV', is a rare, but potentially fatal, disease which usually occurs in the first four weeks of a baby's life.


It is caused by the herpes simplex virus (HSV), the same virus that causes cold sores and genital infections. HSV infections are incredibly common in older children and adults and typically cause mild symptoms, or often no symptoms at all.

There are some simple things you can do to help prevent babies from catching herpes infections.  These include regular hand washing, covering cold sores and not kissing babies who are not your own.


Early recognition and treatment of the virus has been shown to significantly improve babies' chances of making a full recovery (1).

Please note, for simplicity of language, the information below may include the term ‘woman’ or ‘mother’ and this should be taken to include people who do not identify as women but who are pregnant or who have given birth.

What is the herpes simplex virus?


Herpes simplex virus infection in a newborn baby is called neonatal herpes or neonatal HSV. It is typically divided into three categories (2):

  • Infection of the skin, eyes and mouth (SEM)

  • Infection involving the brain (central nervous system/CNS)

  • Infection of multiple organs such as lung, liver, adrenal glands, brain and skin (disseminated)

In young babies who have immature immune systems; HSV infections can spread rapidly if left untreated, causing irreversible cell damage which can lead to permanent disability or death.

Early recognition and prompt treatment with antiviral medication is essential to save the baby's life. Even if treated, a baby may suffer permanent brain damage or die (3).

What is neonatal herpes?


Herpes simplex virus (HSV) is a very common and highly contagious virus which usually spreads from person to person by direct contact. HSV is carried by around 70% of adults in the UK (4).​

Many carriers have no symptoms at all but in others it can lead to cold sores, blisters on the finger (called herpetic whitlow) or genital ulcers/sores. Infections on other areas including the breast are also possible but less common. In older children and adults with normal immune systems, HSV infections are not normally serious and will get better without treatment but if left untreated in young babies it is life-threatening. 

There are two types of HSV:

  • Type 1 (HSV-1) is mainly contracted by oral-to-oral contact to cause orolabial herpes (sores in or around the mouth and lips, such as cold sores) and can also be transmitted through oral sex to cause genital herpes.

  • Type 2 (HSV-2) is mainly sexually transmitted and causes genital herpes.

Herpes infections are most contagious when symptoms are present but can still be transmitted to others in the absence of symptoms as the virus can shed (release into the environment) at any time. Once someone contracts an HSV infection, the virus remains in the body for life. The initial infection is usually the most severe. 

You can read more about the herpes simplex virus in this World Health Organization fact sheet (5).


Babies can become infected in one of three ways (2):

  • During a vaginal birth 'perinatal': through contact with HSV infected secretions in the birth canal. This is the most common source of infection.

  • Contact with the virus after birth 'postnatal': through direct exposure to an active herpes infection on anyone who comes into close contact with the baby, including caregivers and healthcare professionals.

  • In the womb 'in-utero': through the placenta or cervix. This type of infection is rare, accounting for less than 5% of all neonatal herpes infections.

How can a baby catch herpes during birth?

Mothers who have had genital herpes before getting pregnant or who have their first infection early in pregnancy are unlikely to pass an infection on to their baby during delivery (6). This is because, over time, the mother develops protective antibodies which will then pass across the placenta to the baby during pregnancy. Babies are most at risk from neonatal herpes if the mother contracts genital HSV for the first time during the third trimester, as a newly infected mother has not had time to develop antibodies against the herpes virus (2). If there is a known first episode of genital herpes in late pregnancy, mothers may be advised to have a caesarean section to minimise the risk of transmission to their baby (13).

How can a baby catch herpes after birth?

Postnatal transmission usually occurs following contact with an active cold sore, HSV-infected broken skin or HSV blisters on the fingers (herpetic whitlow). Infection can be passed on directly (for example, by a kiss) or indirectly (for example, by touching an area with active infection and then immediately touching the baby). It can also be spread during breastfeeding if the mother has an HSV infection on her breast or nipple (2).


Babies are at greatest risk of postnatal transmission if they do not have antibodies which protect them from the virus. This happens when the mother has never had an HSV infection or if she has her first infection in late pregnancy. This is because there has not been time for the mother to develop and pass antibodies across the placenta. Babies born to mothers who have had an HSV1 infection (for example, cold sores) before they reach their third trimester are much more likely to be protected from acquiring the infection after birth (6).

What if the herpes infection isn't spotted?

It is important to remember that many people with HSV infections will have very mild symptoms, or often none at all, meaning that infections can be missed or put down to another cause. For this reason, some babies can be exposed to the virus before, during or after birth without it being realised. Therefore, it is essential that herpes infection is considered in all young babies who have signs and symptoms of being unwell so that essential treatment can be started as soon as possible (7).

How can a baby catch herpes?


Babies with an HSV infection can become unwell very quickly but the early symptoms may not be very obvious. There is no clear pattern of signs and symptoms that identifies babies with neonatal HSV meaning herpes should be considered in all unwell babies in order to treat them quickly enough (2).

Signs of infection in a baby include (9,10):​

  • Lethargy​/extreme tiredness

  • Irritability

  • High-pitched or abnormal cry

  • Poor feeding

  • Abnormally high or low temperature

  • Floppiness

  • Grunting or difficulty breathing (you may notice the baby 'sucking in' between and underneath their ribs)

  • Rash or sores on the skin, eye or inside the mouth* (but not all babies will have lesions when they first become unwell) 

If you are concerned ​your baby has an infection, seek medical assistance as soon as possible and always ask 'Could it be herpes?'

What are the signs & symptoms of neonatal herpes?
warning sign.png
  • If your baby has any of the following call 999 immediately:

    • Any change in colour to very pale, blue or dusky

    • Difficulty breathing (noisy grunts, rapid breaths, ineffective breathing, pauses between working hard to breathe)

    • Regular jerking of the arms and legs like a fit

*If your baby has a rash or blisters you are unsure about it is important to ask for advice from your doctor or midwife. Babies with localised HSV infection on their skin, eyes or mouth may appear to be otherwise very well but, left untreated, these infections can quickly spread and cause a dangerous disease inside the body.


An antiviral medication is administered into the baby's blood stream (intravenously) typically for 14–21 days. Some babies may require longer treatment (2). The most commonly used medication is called acyclovir. Because babies have small, fragile veins it can be difficult to deliver this medication through a normal cannula (drip) so some babies will have a semi-permanent drip inserted to help give the medication. This will be removed once treatment with intravenous medicine has finished.

Longer term oral antiviral medication might be prescribed after the initial treatment to reduce the risk of a recurrence (2).

Treatment must be given promptly in order to be successful. Babies who are not given antiviral medication quickly may very sadly die (11).

Some babies make a full recovery if they have been given early treatment but, even with treatment, if the infection has spread to the baby's organs it may result in permanent disability or death (11).

What is the treatment for neonatal herpes?


Because some herpes infections do not produce symptoms, the virus can be passed on without anybody realising but there are some simple things you can do to reduce the risk.

If you are pregnant (12):

  • If you have ever had genital herpes (ulcers/blisters/sores) in the past or develop symptoms during your pregnancy then let your doctor/midwife know. They may prescribe oral antiviral medication (13)

  • If you develop genital herpes for the first time during your last trimester then a caesarean birth may be recommended which significantly reduces the risk of transmission during delivery (13)

  • If you are not a known carrier of HSV you should refrain from receiving oral sex in the last trimester of pregnancy especially if your partner has had cold sores in the past.

  • If your partner has active lesions, you should avoid sexual activity in late pregnancy to reduce the risk of catching HSV. Using barrier protection (male or female condoms) can also reduce the risk but it is not 100% effective.

If you are breastfeeding:

  • If you develop lesions on your breast or nipples you should stop feeding from that breast immediately (2) and arrange to see your GP as soon as possible. The lesions should be tested for HSV and treated accordingly.

If you have a cold sore, blister on the fingers (herpetic whitlow) or infected broken skin:

  • You should try and avoid direct contact with newborn babies who are not yours to avoid putting them at risk. If you are the parent or main caregiver or contact is unavoidable you should ensure the lesions are covered and wash your hands thoroughly and regularly. The lesions should be treated with 'topical acyclovir' cream until they heal over (14).

  • Healthcare workers with cold sores or skin lesions should avoid handling newborn babies.

  • If you are the mother and know you carried HSV before your third trimester please remember your baby is likely to be protected against new infections.

Everyone coming into contact with a newborn baby:

  • As people can 'shed' the virus with no symptoms, everyone should wash their hands carefully before holding a young baby (2). Regular and thorough hand washing is essential. Handwashing advice is given below. 

  • Nobody other than the parents should kiss a newborn baby especially if they have a cold sore. Even parents with a cold sore should not kiss their infants until the lesion has healed over (15).

What can I do to pevent my baby getting neonatal herpes?
If you are pregnant or breastfeeding
If you have a cold sore...


Washing hands thoroughly can be a very effective way of preventing the herpes and other viruses passing from person to person including to a newborn baby.

Parents should wash their hands often including on arrival at home and before and after changing the baby's nappy. Visitors to a new baby should also wash their hands on arrival and before holding the baby.


Hands should be washed with soap and water for at least 20 seconds to effectively remove the virus. If soap and water are not available alcohol-based hand sanitiser should be used. Washing your hands properly takes about as long as singing "Happy Birthday" twice using the technique below (16):

How do I wash my hands properly to help keep babies safe?


  1. Nottingham Children's Hospital - Clinical guidelines for neonatal herpes

  2. The New Zealand Herpes Foundation: Neonatal HSV Infection Key Points

  3. MSD Manual Professional Version: Neonatal Herpes Simplex Virus (HSV) Infection

  4. BASHH: 70% of the UK population are infected with HSV1 or HSV2 by the time they are 25 years old

  5. World Health Organization Herpes Simplex Virus Fact Sheet

  6. NCBI: Prevention and management of neonatal herpes simplex virus infections

  7. National Organization for Rare Disorders: Herpes, Neonatal Rare Disease Database entry

  8. Nottingham Children's Hospital: Clinical guidelines for neonatal herpes

  9. NHS: Is your baby or toddler seriously ill?

  10. NHS: Illness in newborn babies

  11. NI Direct: Herpes in a baby (neonatal herpes)

  12. The New Zealand Herpes Foundation: Herpes and Pregnancy

  13. RCOG: Management of Genital Herpes in Pregnancy

  14. Health Protection Surveillance Centre: Neonatal herpes: Frequently Asked Questions

  15. NHS: Neonatal herpes (herpes in a baby)

  16. NHS: How to wash your hands

bottom of page