Cold sores can seriously harm or kill newborn babies

What the research found

Reviews describe neonatal herpes as potentially devastating. A 2020 review says infection in the first 4 to 6 weeks of life can lead to neurological complications and even death. A 2021 review says illness and death rates in affected newborns remain high, despite better treatment since the 1980s.

A 1998 review noted that cold sores (herpes labialis), caused mainly by HSV-1, may cause significant illness and death in newborns exposed during delivery. Official guidance from the NHS says a baby can catch herpes if someone with a cold sore kisses them. Victorian health guidance says primary infections are more likely to be severe in newborns.

Neonatal herpes is described as rare in the UK. Genital herpes in the mother is another route, and the risk is highest when a mother gets herpes for the first time late in pregnancy. Cold sores are one route, but not the only one.

What it doesn’t mean

• This does not mean every exposure leads to infection. Neonatal herpes is rare, and most adults carry the virus. The risk is greatest in the first 6 weeks.
• Simple steps cut the risk. Wash hands before handling a baby. Anyone with a cold sore should not kiss the baby. Avoid kissing near a newborn's mouth, nose or eyes.
• See a GP straight away if a young baby is irritable, feeding poorly, has a fever of 38C or more, or has sores or a rash. Call emergency services if the baby is floppy, hard to wake, has a seizure or has trouble breathing.