Neonatal herpes is a herpes infection in a young baby. The younger the baby, the more vulnerable they are to the harmful effects of infection.

Herpes can be very serious for a young baby, whose immune system might not have fully developed to fight off the virus.

Neonatal herpes, which is rare in the UK, is caused by the herpes simplex virus. This virus is very common and causes cold sores, genital ulcers and herpetic whitlow (a type of finger infection) in adults.

Neonatal herpes can be prevented by following some simple advice.

If you have genital herpes for the first time in your 3rd trimester of pregnancy, particularly during the last 6 weeks, your newborn baby is at risk of catching herpes.

There's a risk you could pass the infection on to your baby if you have a vaginal birth.

The risk is much lower if you've previously had genital herpes or you are infected with genital herpes for the first time during the early stages of pregnancy.

After birth

The herpes simplex virus can be passed to a baby through a cold sore if a person has a cold sore and kisses the baby.

The herpes virus can also be spread to your baby if you have a blister caused by herpes on your breast and you feed your baby with the affected breast or expressed breast milk from the affected breast.

Blisters on your fingers caused by infection (herpetic whitlow) may also spread the virus.

It is thought that your baby can be most at risk of getting a herpes infection in the first 6 weeks after birth.

The following advice can reduce the risk of your baby getting infected by the herpes virus during this time.

• Everyone should wash their hands before handling your baby.
• Discourage anyone who is not a close family member or carer from kissing your baby.
• The safest place to kiss your baby is on the top of their head. Kissing your baby near their mouth, nose or eyes should be avoided.
• People with a current cold sore, or a recent history of cold sores, should not kiss your baby.
• People with a known herpes infection, such as a cold sore or herpes blister, should avoid touching your baby unless they are a close family member or carer, and in that case, they should carefully wash their hands first.

A newborn baby has an underdeveloped immune system, which means they can quickly become seriously ill after catching herpes. Babies born prematurely are particularly at risk.

Call a GP or NHS 111 straight away if your baby:

• is irritable and will not settle
• is not feeding as well as usual
• has a high temperature (fever) of 38C or more – find out how to take your baby's temperature
• has a rash or sores on their skin, eyes and inside their mouth

These are early warning signs that your baby is unwell and may need urgent treatment.

Call 999 immediately if your baby:

• is lacking in energy (lethargic and listless)
• has a rash that does not fade when a glass is rolled over it (but a rash will not always develop) – this rash may be harder to see on brown and black skin
• is becoming floppy
• is not responding to you in their normal way
• is difficult to wake up from sleep
• is breathing rapidly, has difficulty breathing, or makes noises when breathing (grunting)
• has a seizure (fit)
• is peeing less than normal
• is crying constantly and you cannot soothe or distract them, or their cry does not sound like their normal cry
• has a blue tongue or skin (cyanosis) – if they have brown or black skin this may be easier to see on their lips, tongue and gums, under their nails and around their eyes

Very often the baby will not have any specific herpes symptoms, such as a rash or blisters.

But they can become unwell very quickly, so you need to act fast.

Neonatal herpes is usually treated with antiviral medicines given directly into the baby's vein (intravenously).

This treatment may be needed for several weeks.

Any related complications, such as fits (seizures), will also need to be treated.

You can breastfeed your baby while they're receiving treatment, unless you have herpes sores around your nipples.

If you are taking antiviral treatment too, this can be excreted in your breast milk, but is not thought to cause any harm to your baby.

Sometimes neonatal herpes will only affect the baby's eyes, mouth or skin.

In these cases, most babies will make a complete recovery with antiviral treatment.

But the condition is much more serious if it has spread to the baby's organs.

Some infants with this type of neonatal herpes can die, even after they have been treated.

If widespread herpes is not treated immediately, there's a small chance the baby will die and around 1 in 2 babies that do survive are left with a permanent disability or complication.

If you're pregnant and have a history of genital herpes, tell your doctor or midwife.

It's also very important to tell your doctor or midwife if you think you have the symptoms of genital herpes during your pregnancy. This is particularly important if this is the first time you think you've had the virus.

Getting genital herpes treated as soon as possible will reduce the risk to your baby.

If your partner has herpes symptoms then you should use a condom during sex, especially in your 3rd trimester.

You may need to take medicine during the 3rd trimester of your pregnancy to prevent an outbreak of vaginal sores during labour.

Birth by caesarean section is recommended if the genital herpes has occurred for the first time in your 3rd trimester, particularly the last 6 weeks of your pregnancy. You may also need to take medicines after birth if you develop herpes blisters on your breasts.

If you develop a cold sore or have any signs of a herpes infection, take these precautions:

• do not kiss any babies
• wash your hands before contact with a baby
• wash your hands before breastfeeding
• if you develop any blisters on your breast do not feed from it until all the blisters are healed
• cover up any cold sores, lesions or signs of a herpes infection anywhere on your body to avoid passing on the virus

You may find these resources helpful:

• cold sores
• genital herpes
• herpetic whitlow (whitlow finger)
• Sands: a charity that provides support for anyone affected by the death of a baby
• World Health Organization (WHO): herpes simplex virus