Respiratory syncytial virus (RSV) is a common cause of respiratory infection. It mostly affects young children. RSV symptoms are usually mild. However, some young children can get very sick and need hospital treatment.

Some babies in NSW are eligible to receive an immunisation to help protect them against severe illness from RSV. This immunisation is called Beyfortus(nirsevimab).

Last updated: 26 April 2024

What is respiratory syncytial virus (RSV)?

Respiratory syncytial virus ( RSV) causes respiratory infections. RSV mostly affects babies and children but adults can also get sick from RSV. Most infections in NSW happen in the cooler months of late autumn or winter.

Most people only get mild symptoms. Symptoms usually begin around 2 to 8 days after exposure to the virus.

Symptoms can include:

  • runny nose
  • cough
  • wheeze
  • difficulty breathing
  • fever
  • cyanosis (bluish or greyish colour of the skin).

Babies under one year of age are more likely to get breathing problems from an RSV infection. This can include bronchiolitis or pneumonia. Babies may be unsettled or have trouble with feeding.

What is Beyfortus(nirsevimab)?

Beyfortus (nirsevimab) is a medicine that can protect babies and young children against severe illness from RSV.

Beyfortus (nirsevimab) is not a vaccine. It is a type of immunity that occurs when a person is given antibodies rather than making it through their own immune system. Beyfortus (nirsevimab) contains pre-made RSV antibodies that protect the body from illness. These antibodies give protection almost immediately after the immunisation.

Medical studies have shown Beyfortus(nirsevimab) to be around 80 percent effective in preventing children from being hospitalised with RSV during the RSV season.

The antibodies last for at least 5 months, but disappear after this time.

Who is at highest risk from RSV?

Some children are at higher risk of severe illness from RSV, including:

  • babies aged 12 months and under, especially those aged 6 months and under
  • young children aged 2 years and under with medical conditions such as chronic lung disease or congenital heart disease
  • babies and young children aged 2 and under who were born pre-term or with a low birth-weight
  • Aboriginal and/or Torres Strait Islander infants and young children aged 2 years and under

Infants aged 12 months and under are more likely to develop breathing problems due to RSV, such as bronchiolitis or pneumonia. Children who get severely unwell may need to go to hospital.

RSV immunisation


What is the NSW Health RSV vulnerable babies program?

Due to limited global availability of Beyfortus (nirsevimab), in NSW, only babies who are at higher risk of severe illness from RSV are eligible for Beyfortus (nirsevimab) under the NSW Health RSV vulnerable babies program.  

The program commenced on 25 March 2024. It will run during the RSV season from March to September 2024.

Is my child eligible for Beyfortus (nirsevimab)?

Beyfortus (nirsevimab) will be offered to infants in 2024 who meet the following eligibility criteria:

  • babies born before 37 weeks gestation and after 31 October 2023
  • Aboriginal and Torres Strait Islander babies born after 31 October 2023
  • other infants living with specific chronic and complex health conditions.

Further information about the eligibility for Beyfortus(nirsevimab) is available on the NSW Health webpage.

Beyfortus (nirsevimab) can only be accessed from clinicians in treating hospitals.

Can Beyfortus (nirsevimab) be given at the same time as childhood vaccines?

Babies can receive Beyfortus (nirsevimab) at the same time as routinely recommended childhood vaccines. 

How is the injection given?

As per the Australian Technical Advisory Group on Immunisation (ATAGI) clinical advice, for infants born during or entering their first RSV season, the recommended dose for Beyfortus (nirsevimab) is: 

  • 50 mg in 0.5 mL if weight is less than 5 kg
  • 100 mg in 1 mL if weight is equal to or greater than 5 kg

Beyfortus (nirsevimab) is given as an injection in the muscle, usually in the outer part of the thigh.

Some children who weigh more than 5 kg may need two injections if a 100mg dose is not available.

Could the injection cause RSV illness?

No, the immunisation does not contain RSV and it cannot cause RSV illness.

What are the side effects of Beyfortus (nirsevimab)?

In medical trials, Beyfortus (nirsevimab) caused no side effects in most infants.

If any side effects did occur, they were most commonly tenderness, redness or swelling where the injection was given. These reactions usually go away within a few days.

You can call healthdirect on 1800 022 222 (24 hours) for non-urgent advice on managing side effects if needed. If you are concerned about your baby, you should seek medical advice.

Where will my child’s immunisation be recorded?

Your baby’s immunisation with Beyfortus (nirsevimab) will be recorded on the Australian Immunisation Register (AIR).

Your baby’s immunisation record can be accessed on the MyGov website and by logging into your Medicare account.

Other resources

Talk to your child’s doctor about Beyfortus(nirsevimab).

More information can be found in the Consumer Medicine Information leaflet for Beyfortus (nirsevimab), or ask the doctor for a copy of the Consumer Medicine Information leaflet.

The Sydney Children’s Hospitals Network also has information about Respiratory syncytial virus (RSV) monoclonal antibody.

Current as at: Friday 26 April 2024
Contact page owner: Immunisation