Introduction

Respiratory syncytial virus (RSV) is a virus that can cause the common cold. RSV is very contagious in young children and can cause severe infections that affect breathing. 

These include:

  • bronchiolitis – when the small breathing tubes in the lungs become narrow and inflamed
  • pneumonia – when the air sacs in the lungs become infected.

Children who are at a higher risk of severe RSV and respiratory illness include:

  • babies born before 37 weeks of pregnancy
  • babies born with a low birth weight
  • babies under 12 months old
  • children under two years old who have other medical conditions.

Immunisation against RSV is the best way to protect your child from getting severe RSV and other respiratory illnesses. 

 Immunisation for RSV

An RSV monoclonal antibody can be given for the prevention of RSV.

A monoclonal antibody is a type of protein made in a laboratory that helps the body fight harmful cells or viruses.

A monoclonal antibody immunisation is a fluid made up of these antibodies that is injected into the bloodstream.

When the antibodies enter the bloodstream, they attach to the RSV virus like a shield and help to block it from infecting healthy cells.

Two monoclonal antibodies are currently available for babies and young children in Australia.

Beyfortus (nirsevimab)

Beyfortus (nirsevimab) is the newest monoclonal antibody for RSV.

It can be given as a single injection to:

  • babies from birth to 12 months old
  • children aged two years who have other medical conditions and are at risk of severe RSV.

Beyfortus (nirsevimab) has been clinically trialled since 2016. It became available for use in Australia in 2024. 

Clinical trials show that Beyfortus (nirsevimab):

  • protects against severe RSV for around five months
  • reduces the risk of hospitalisation due to RSV by about 80%.

Synagis (palivizumab)

Synagis (palivizumab) is a monthly monoclonal antibody injection. It is given to children under two years old who have other medical conditions and are at risk of severe RSV.

Synagis (palivizumab) has been used in Australia since 1998.  

Clinical trials show that Synagis (palivizumab):

  • protects against severe RSV for around one month
  • reduces the risk of hospitalisation due to RSV by about 50%.

Before the immunisation

Your baby can still have the monoclonal antibody immunisation for RSV if they have:

  • a cough or cold
  • a mild fever.

Talk to your doctor or specialist about any of your baby’s medical conditions and tell the doctor if your baby has:

  • reacted to an immunisation or a vaccine before
  • a bleeding condition.

During the immunisation

The monoclonal antibody immunisation for RSV is given by a healthcare professional and injected directly into your baby’s outer thigh muscle.

 After the immunisation

Side effects

The risk of side effects from the monoclonal antibody immunisation for RSV is small. 

Side effects are usually mild and can include:

  • pain, redness, swelling and hardness on the skin where the needle was given
  • rash
  • fever.

If you have concerns or questions about the RSV immunisation and side effects, speak to:

  • your paediatrician
  • your local doctor
  • Health Direct by calling 1800 022 222.

In an emergency, call triple zero (000) for an ambulance or go to your nearest emergency department.

Caring for your child

Mild side effects from monoclonal antibody immunisation for RSV can be managed at home with:

  • over-the-counter pain relief like paracetamol or ibuprofen for mild fever or discomfort
  • a cold compress or wet washcloth on any swelling.

Resources and more information