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Newborn & baby health centre

Infections in newborn babies

Newborn babies sometimes develop infections because their immune systems are not mature enough to fight off the viruses and bacteria that can cause infections.

It’s an obvious cause for concern as newborns can get ill very quickly. They can also respond very quickly to treatment.

For bacterial infections babies will usually be given antibiotics. Antibiotics aren’t used for viral infections. There are some antiviral drugs that can be used for specific viral infections.

Depending on the infection, and its severity, newborns may be treated in a hospital’s neonatal intensive care unit.

Signs of an infection

The signs for many infections are similar, so look out for:

  • Difficulty breathing
  • Poor feeding
  • Rise or fall in temperature
  • Rash or skin colour change
  • Constant crying
  • Marked change in behaviour
  • Listlessness

Always seek medical attention immediately if your baby is showing any signs of possible infection.

Group B streptococcus infection

Most infections in newborn babies are caused by bacteria called group B streptococcus, also known as group B strep or GBS.

The bacteria are carried by around 1 in 5 pregnant women. In a small number of cases they can infect the baby.

The NHS estimates that about 1 in 2,000 newborn babies born in the UK and Ireland develops GBS.

The bacteria can be passed on from a mother to her baby during birth.

It can cause blood infection (sepsis), lung infection ( pneumonia) or infection of the fluid and lining around the brain ( meningitis).

If your baby gets group B strep infection in the first 7 days of life, it's called early-onset infection. It’s thought that babies who get an infection soon after they are born breathed in fluid that contained group B strep during labour.

It can be prevented by giving women antibiotics during labour to kill the bacteria before they’re passed onto the child.

Your baby is more likely to be at risk of developing a group B strep infection if:

  • You carry the bacteria in your body without symptoms of an infection
  • Your baby is born prematurely (before the 37th week of pregnancy)
  • You have a fever during labour
  • Your waters break early
  • Your baby weighs less than 2.5 kilograms (5.5lbs).


Late-onset infections

If your baby gets group B strep infection between 7 days and 2 months after birth, it's classed as late-onset infection.

Doctors aren't exactly certain how a baby gets late-onset infection. It seems that mothers probably pass group B strep to their babies through close physical contact. Giving women antibiotics during labour doesn't prevent babies getting late-onset infections.


Listeriosis is another type of infection that has similar symptoms to group B strep in babies. Babies can pick up the bacteria from their mothers if they contract listeriosis when pregnant, through eating contaminated foods or foods that aren’t cooked or cleaned properly. The woman may carry the bacteria in her cervix or vagina. Babies less than 1 month old are considered an at risk group.

WebMD Medical Reference

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