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Newborn babies

Cold sores (babies and children)

The cold sore virus can be dangerous for young babies and even fatal. The risk is highest in the first 4 weeks after birth.

If you have a newborn baby and think you have a cold sore

If you develop a cold sore or think you're coming down with a herpes infection, take these precautions:

  • do not kiss your baby
  • wash your hands before contact with your baby
  • cover up any cold sores before breastfeeding to avoid touching your mouth and then your breast. This is enough to transfer the virus

Make sure visitors take the same precautions.

Neonatal herpes

If a newborn baby catches the herpes simplex virus, they can get neonatal herpes.

Neonatal herpes is a herpes infection in a newborn baby. It is caused by the cold sore virus (herpes simplex). Neonatal herpes can be very serious for young babies. Their immune systems haven’t developed enough to fight off the infection.

How babies catch neonatal herpes

Babies can catch neonatal herpes:

  • during the pregnancy or vaginal birth. This happens if the mother had genital herpes for the first time in the last 6 weeks of her pregnancy
  • after the birth – if someone with a cold sore kisses the baby. Or if a breastfeeding mother has cold sore blisters on her breast


Babies with neonatal herpes don’t always get the cold sore blisters. But they can become unwell quickly. Act fast if you are worried about your baby. Or if you think they might have neonatal herpes.

Get advice from your GP urgently if your baby:

  • isn’t feeding
  • is irritable
  • has a high temperature (fever over 38°C)
  • has a rash, blisters or sores on their skin, eyes or inside their mouth

Trust your instincts. If you think something is not right with your baby, always speak to your GP or public health nurse.

When to call 112 or 999

Call 112 or 999 if your baby:

  • won’t wake up (unresponsive)
  • is difficult to wake
  • is having trouble breathing, is breathing fast or is making grunting noises
  • has a blue tongue, lips or skin
  • has a seizure (fit or convulsion)


If your baby gets neonatal herpes they are usually given antiviral medication. This is given through a drip into their veins. Most babies continue to breastfeed while being treated. Speak to your doctor first if you have blisters on your breast or around your nipples.


Most babies make a full recovery with treatment.

But in rare situations the infection can spread to the baby’s organs. Around one-third of babies that this happens to will die.

How to prevent neonatal herpes

If you are pregnant and have had genital herpes in the past, tell your GP, obstetrician or midwife. Your doctor may prescribe anti-viral medicine to take in the last 4 weeks of pregnancy. This helps prevent you getting a genital herpes attack during labour.

If you get genital herpes during the last 6 weeks of your pregnancy, you might have a caesarean birth.

If you develop a cold sore, or think you're coming down with a herpes infection:

  • don’t kiss any babies
  • wash your hands with warm water and soap before contact with a baby
  • wash your hands before breastfeeding. Cover up any cold sores to avoid touching your mouth and then breast. This is enough to transfer the virus

page last reviewed: 17/05/2019
next review due: 17/05/2022