What is it?

Respiratory syncytial virus (RSV) is a virus that causes both upper and lower respiratory tract infections. Children under 1 year of age, individuals with underlying medical conditions (e.g. chronic cardiac and lung disease), the older population and immunocompromised people are more likely to experience serious disease requiring hospitalisation. 

What to look for

Cold-like symptoms such as rhinorrhoea (runny nose), fever, wheeze, headache and cough are common. Symptoms generally appear 1 to 5 days after exposure and can last 8 to 15 days.  

Symptoms may progress to shortness of breath, wheezing, bronchospasm and feeding problems (in children). One third of children develop otitis media (ear infections).  

Whilst most infections are mild, bronchiolitis (inflammation of the small airways) and pneumonia (lung infection) can occur and may lead to hospitalisation for supportive measures such as oxygen therapy and rehydration. It is estimated that bacterial co-infections occur in around 30% of hospitalised patients. In older adults, RSV can exacerbate chronic obstructive pulmonary disease or lead to heart failure.  

How is it transmitted?

RSV is highly contagious and can be transmitted via the inhalation of droplets containing the virus. RSV can also be transmitted when a person touches a contaminated surface and then touches their face. 

People with RSV are generally considered infectious for 3 to 8 days. However, some people continue to spread the virus for up to 4 weeks. 


Children and older adults have the highest rates of RSV infection. Almost all children will have experienced infection by the age of 2 years. Aboriginal and Torres Strait Islander adults are at greater risk of RSV-associated hospitalisation than non-Indigenous adults. Reinfection occurs throughout the lifetime since natural infection does not provide long-term immunity. 

RSV infections are commonly seasonal, with a peak in cases usually seen over autumn and winter in temperate climates, and during the rainy season in tropical climates.  In recent years, RSV notification rates have increased significantly in Australia.  


Practising good hand hygiene is important in preventing infections. Previous infection with RSV can provide some immunity but this protection is not long term.

Monoclonal antibodies

Monoclonal antibodies are a type of immunoglobulin, or immune system proteins. They are a medication that can aid the body’s immune response to help prevent disease. There are two monoclonal antibodies approved for use to prevent RSV in Australia:  

  • Palivizumab (Synagis) 
  • Nirsevimab (Beyfortus) 

Palivizumab is available for some infants who are considered at higher risk of developing severe disease from RSV infection (due to medical conditions such as prematurity, chronic lung disease and specific cardiac conditions). Doses are calculated according to the infant’s weight and administered via intramuscular injection every month over the winter period (usually May to October in southern Australia). Palivizumab can be privately purchased and may be funded for infants by their individual hospital. 

Nirsevimab can be administered from birth as a single intramuscular injection offering protection for at least 5 months. It is recommended for all infants entering their first RSV season. Children with a high risk of severe RSV disease due to medical conditions may also consider another dose before going into their second RSV season. Nirsevimab is not currently funded through the NIP, however various jurisdictions have announced state-funded programs. 

Co-administration with vaccines 

Nirsevimab or Palivizumab can be given on the same day as all vaccines.  

Side effects 

Side effects from monoclonal antibodies are not common but can include injection site tenderness and swelling, mild respiratory symptoms and rash. Nirsevimab can in rare circumstances cause fever within 7 days.  


Arexvy is a vaccine available for the prevention of RSV infection. It is an adjuvanted recombinant vaccine requiring a single dose of 0.5 mL administered intramuscularly. It can be co-administered with all other vaccines and can be administered at any time of year. Arexvy is currently only available through private purchase.  

Whilst Arexvy is registered and available or use in all individuals aged 60 years and over, ATAGI recommends its use in: 

  • all adults aged 75 years and over  
  • Aboriginal and Torres Strait Islander adults aged 60-74 years 
  • adults 60-74 years with specified medical conditions. 

Booster doses of Arexvy are not currently recommended. 

Side effects

Common side effects following administration of Arexvy include injection site reactions (pain, redness and swelling), malaise, headache and fatigue. These side effects generally occur in the first 48 hours following vaccination and last 1-2 days.  

Symptoms can be managed at home with supportive measures such as a cold compress and oral analgesia. Antibiotics, antihistamines and steroids are not recommended to treat injection site reactions, which are caused by an inflammatory response to the vaccine and are not the result of an infection or allergy.

Precautions and contraindications

Use of Arexvy is contraindicated in any person who has experienced anaphylaxis to a previous dose or anaphylaxis to any component of Arexvy.  

It should not be administered to infants or pregnant women due to a lack of safety and efficacy data. Should inadvertent administration occur, a report to a vaccine safety service (SAEFVIC in Victoria) should be submitted and the patient informed using the open disclosure process. Adverse events should be monitored. 

Authors: Georgina Lewis (Clinical Manager SAEFVIC, Murdoch Children’s Research Institute) and Rachael McGuire (MVEC Education Nurse Coordinator)

Reviewed by: Rachael McGuire (MVEC Education Nurse Coordinator)

Date: April 2024

Materials in this section are updated as new information and vaccines become available. The Melbourne Vaccine Education Centre (MVEC) staff regularly reviews materials for accuracy.

You should not consider the information on this site to be specific, professional medical advice for your personal health or for your family’s personal health. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult a healthcare professional.