In Australia, respiratory syncytial virus (RSV), causing bronchiolitis, is the most frequent cause of hospitalisation in children under 12 months old.  Every year approximately 6000 infants need care at the hospital.   

Infants account for 80% of all hospitalisation related to RSV.  

Respiratory syncytial virus season is generally between March to September, peaking between April and July.  

A new respiratory syncytial virus (RSV) monoclonal antibody (mAB), Beyfortus (nirsevimab), was made available in Australia in early 2024.  Beyfortus is not a vaccination, it is an immunisation.    

The immunisation is approved for use in:  

• neonates and infants entering or born during their first RSV season (March to September)   
• children under 24 months old who remain vulnerable to severe RSV through their second RSV season.  

Beyfortus is used for protection against RSV and has been shown to decrease the risk of hospitalisation for severe RSV in infants and children.  Beyfortus protects infants and children for approximately 5 months, equivalent to one RSV season.