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 (the sudden tightening of lung muscles) and feeding problems (in children). One third of children develop otitis media (ear infection).
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.
Epidemiology
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.
The Paediatric Active Enhanced Disease Surveillance (PAEDS) network monitors data on children admitted to hospital with RSV infections through enhanced site surveillance in Australia, including RCH and Monash Health in Victoria. This data is updated monthly and can be accessed via PAEDS: Paediatric RSV in Australia.
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.
Prevention
Previous infection with RSV can provide some immunity but this protection is only short term. Multiple infections can occur within the same year.
Both monoclonal antibodies and vaccines are available in Australia for RSV prevention, and are recommended for specific populations. Previous infection with RSV is not a contraindication to receipt of preventative products.
Monoclonal antibodies
Monoclonal antibodies are a type of immunoglobulin (immune system protein) that can be administered to provide passive immunity (short‑term protection gained from donated antibodies). In Australia, there are two RSV monoclonal antibodies available for use in infants and young children only (from birth to under 2 years):
- Nirsevimab (Beyfortus)
- Palivizumab (Synagis).
Nirsevimab requires a single intramuscular injection which can provide protection for up to 6 months. In Australia, Nirsevimab is funded for some infants through state/territory infant immunisation programs (refer to NCIRS: State and territory nirsevimab (Beyfortus) infant program summary 2025 for information on jurisdictional programs). Palivizumab may be used as an alternative when Nirsevimab is unavailable.
Recommendations
Nirsevimab can be administered from birth, with some jurisdictions offering catch up to older infants (up to 2 years, with the upper limit varying between jurisdictions). It is recommended for all infants:
- whose mother did not receive RSV vaccination during pregnancy (maternal vaccination)
- born < 2 weeks after maternal RSV vaccination
- at increased risk of severe RSV, regardless of their mother’s vaccination status
- born to mothers with severe immunosuppression (due to the reduced immune response to maternal RSV vaccination)
- whose passive protection from maternal immunisation is ineffective, for example an infant who required extracorporeal membrane oxygenation (ECMO) or cardiopulmonary bypass (CPB), or whose mother required ECMO or CPB after vaccination.
Table 1: Monoclonal antibody recommendations for infants up to 8 months of age
| Monoclonal antibody (brand name) | Preparation | Dose | Route | Frequency |
| Nirsevimab (Beyfortus) | 2 strengths available: 50 mg/0.5 mL OR 100 mg/mL* | 50 mg for infants weighing < 5 kg* 100 mg for infants weighing > 5 kg | IM | Single dose only |
*The 100 mg/mL preparation should never be halved and used for a patient weighing < 5 kg.
Nirsevimab is also recommended for some children aged 8 to 24 months who remain at risk of severe disease (refer to individual state or territory program for recommendations for First Nations children and the Australian Immunisation Handbook: Conditions associated with increased risk of severe RSV disease in infants and young children for a list of specified medical conditions). These children should receive nirsevimab regardless of maternal vaccination or whether they received a dose in their first RSV season. An interval of 2 to 6 months between doses of nirsevimab is recommended for children who previously received a dose (except in the setting of ECMO or cardiopulmonary bypass- refer to Additional doses below).
Table 2: Monoclonal antibody recommendations for at-risk children aged 8 to 24 months*
| Weight | Dose | Preparation |
| < 5 kg | 50 mg^ | 1 X 50 mg/0.5 mL |
| 5 to < 10 kg | 100 mg | 1 X 100 mg/mL |
| > 10 kg | 200 mg | 2 X 100 mg/mL# |
* MVEC acknowledges that these recommendations differ from the dosage guidelines outlined in the Australian Immunisation Handbook. Immunisation specialists at the Royal Children’s Hospital preferentially recommend that doses of nirsevimab for children entering their second RSV season should be based on the child’s current weight.
^ The 100 mg/mL preparation should never be halved and used for a patient weighing < 5 kg.
# 2 doses of product should never be combined into one syringe. Instead administer 2 complete doses into separate limbs, or in a single limb, ensuring there is a spacing of 2.5 cm. Doses should be administered at the same visit.
Additional doses
Children undergoing CPB or ECMO should receive an additional dose of nirsevimab as soon as they are stable. Refer to the Australian Immunisation Handbook: Dose and route for recommended dosages and timing.
Co-administration with vaccines
Nirsevimab or palivizumab can be given on the same day as all vaccines. For advice on giving multiple injections, refer to MVEC: Vaccine administration.
Side effects
Side effects from monoclonal antibodies are uncommon but can include injection site tenderness and swelling.
Vaccines
There are two RSV vaccines available for use in adults only (not infants/children) within Australia:
- Arexvy
- Abrysvo.
Recommendations
RSV vaccination is available to adults only (vaccines are not registered for use in children). Vaccination is recommended for the following groups, funding varies between groups:
- all adults aged 75 years and over (funded as of 15 May 2026)
- Aboriginal and Torres Strait Islander adults aged 60 years and over (funded as of 15 May 2026)
- adults with specified medical conditions aged 60 to 74 years (not funded)
- pregnant people from 28 weeks’ gestation in every pregnancy, to protect their newborn (funded)
- Abrysvo only, Arexvy must not be given to pregnant people.
Clinical trials demonstrate that when vaccinated against RSV during pregnancy the risks of hospitalisation due to severe RSV infection is reduced by 57% for infants less than 6 months of age.
Vaccination can be considered (unfunded) for other groups of adults and is available for private purchase:
- adults aged 50 to 59 years with specified medical conditions
- non-Indigenous adults aged 60 to 74 years with no specified medical conditions.
Table 3: RSV vaccine brand by population group
| Population group | Vaccine brand and dose and route | |
| Abrysvo (0.5 mL) IM | Arexvy (0. 5mL) IM | |
| Pregnant people from 28 weeks gestation* | ✓* | # |
| Adults with specified medical conditions aged 50-59 years^ | ✓^ | |
| Adults with specified medical conditions aged 60-74 years | ✓ | ✓ |
| First Nations adults ≥ 60 years | ✓ | ✓ |
| Non-Indigenous adults with no specified medical conditions aged 60–74 years^ | ✓^ | ✓^ |
| All adults ≥ 75 years | ✓ | ✓ |
* If the infant is born less that 2 weeks after maternal vaccination, they will not be adequately protected and should receive nirsevimab at birth.
# Arexvy must not be administered to pregnant people. There is no data on the safety and efficacy of administration of Arexvy in pregnant people. Abrysvo is the only RSV vaccine suitable for use in pregnancy.
^ Vaccination can be considered.
shaded boxes indicate vaccines funded under the NIP for eligible individuals.
shaded boxes not registered for use in this age group.
Co‑administration with other vaccines
It is safe to administer RSV vaccines on the same day as other vaccines. For advice on giving multiple injections, refer to MVEC: Vaccine administration.
Side effects
Common side effects following administration of Arexvy or Abrysvo 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 to 2 days.
A very small number of cases of Guillain-Barre Syndrome (GBS) have been reported in adults aged over 60 years who have recently received RSV vaccination (Arexvy or Abrysvo). GBS is an auto-immune condition, often triggered by a bacterial or viral infection. Given the potential severity of RSV infection in older adults and rare risk of GBS, the benefits of RSV vaccination far outweigh potential risks. Refer to TGA: Updated warnings for Respiratory Syncytial Virus vaccines Arexvy and Abrysvo for more information.
Precautions and contraindications
RSV vaccines are not registered for use in children and should not be confused with monoclonal antibodies.
Arexvy must not be administered to pregnant women due to a lack of safety and efficacy data. Should inadvertent administration occur, it should be reported to the adverse event reporting service in your jurisdiction and the patient should be informed using the open disclosure process.
Commonly asked questions
Can pregnant people under 18 years of age receive Abrysvo?
Yes, Abrysvo is recommended and funded for all pregnant people. Vaccine safety and efficacy in people less than 18 years is expected to be the same as people aged 18 years and over.
Are booster doses of RSV vaccine required for older adults?
Evidence suggests that a single dose of RSV vaccine given to older adults provides protection for approximately 2 years. At this stage there is no recommendation for booster doses.
I am an older adult and I privately purchased an RSV vaccine in 2025, should I receive a funded dose in 2026?
There are no recommendations for booster doses of RSV vaccine at this stage. If an older adult previously received a dose in 2025 they are not recommended to receive another dose in 2026.
Is there an increased risk of preterm birth associated with RSV vaccines in pregnancy?
Current data has not demonstrated a statistically significant increased risk of preterm birth associated with Abrysvo, the licensed RSV vaccine in pregnancy. Careful monitoring of vaccine safety will be ongoing.
Clinical vaccine trials involving pregnant women follow additional protocols to carefully monitor outcomes specific to pregnancy and newborns, including prematurity (birth at < 37 weeks’ gestation).
A clinical trial of a GSK RSV vaccine (not Abrysvo) in pregnancy found more cases of preterm birth in the vaccine group compared with the placebo group (6.8% vs 4.9%). This difference was statistically significant, and led to the clinical trial being halted and an application for licensure was never submitted. (Statistically significant means the difference between groups, vaccine vs placebo, is unlikely to have occurred by chance alone.) Notably, this finding was not consistent across the trial. The imbalance in preterm birth occurred in low‑ and middle-income countries, but not high‑income countries. And, it occurred only during a certain period of the trial (April–Dec 2021). Despite extensive additional research examining why the imbalance in preterm birth might have occurred, reasons remain unclear.
These events heightened the focus on preterm birth as an important potential safety signal to monitor for RSV vaccines in pregnancy generally.
Abrysvo is currently the only RSV vaccine licensed for use in pregnancy. Clinical trials of Abrysvo found slightly more cases of preterm birth in the vaccinated group than the control group, but this difference was not statistically significant (5.7% vs 4.7%). Most preterm births in both groups were late preterm (34 to < 37 weeks’ gestation).
In August 2023, the US FDA licensed Abrysvo for use in pregnancy between 32 and 36 weeks. This was a precautionary approach, to avoid potential risks for preterm birth. Balancing the need to protect premature infants from RSV infection, the UK and Australia have recommended RSV vaccine from 28 to 36 weeks’ gestation. In Europe, RSV vaccines are recommended from 24 to 36 weeks’ gestation.
The safety of RSV vaccines in pregnancy has continued to be closely monitored following rollout of vaccine programs internationally. Post‑market safety data from the US have been reassuring, and consistent with trial safety data. Preliminary results from a large US‑based data–linkage study, examining thousands of pairs of pregnant women (one vaccinated and one unvaccinated in each pair), found no increased risk of preterm birth in the vaccinated group. Another US‑based retrospective cohort study from New York City similarly found no increased risk of preterm birth for vaccinated women. Safety monitoring systems in Australia, through the TGA and local vaccine safety services such as SAEFVIC, are closely monitoring any potential adverse events in Australia.
These real‑world studies are important, as they include larger numbers and a larger variety of patients than were included in clinical trials.
Additionally, pregnancy outcomes such as preterm birth occur for a variety of reasons. Knowing background rates of preterm birth in a given population can help in understanding whether preterm births seen in vaccinated women are more than expected. Ongoing monitoring of the safety of RSV vaccines in pregnancy, using a variety of data‑sources and methods, will continue.
Will RSV prevention products be recorded on AIR?
Yes, Nirsevimab (infant monoclonal antibody), Abrysvo (for use in pregnancy and adults > 60 years) and Arexvy (for use in adults > 60 years only) must be recorded on the Australian Immunisation Register (AIR). It is important to maintain accurate records of a person’s protection.
When recording maternal vaccination during pregnancy, the “Vaccine type” should be marked as “antenatal”.
Why vaccinate in pregnancy all year round, including towards the end of the year, if an infant will no longer be protected by the time RSV season starts (6 months later)?
RSV season in Australia is typically from May to October (in temperate climates). However, infections can and do occur all year round.
The RSV mother and infant protection program (RSV-MIPP) aims to reduce the likelihood of infections occurring in infants aged under 6 months, the age at which it is more common for infections to be severe. Maternal vaccination protects an infant at a time when they are most vulnerable.
Further, the exact time of delivery is difficult to predict. An infant’s six months of protection could fall in a different period than expected.
Is a pregnant person no longer eligible for vaccination if they are beyond 36 weeks' gestation?
Whilst the recommendation for maternal RSV vaccination is for administration between 28 and 36 weeks’ gestation, a person can still be offered vaccination after this time. There are no safety concerns if the vaccine is administered after 36 weeks.
If the infant is born sooner than 2 weeks after the maternal vaccination, they will not be adequately protected and should therefore receive (in addition) Nirsevemab at birth.
If an infant has had confirmed RSV infection should they still receive nirsevimab?
Previous infection with RSV can provide some immunity but this protection is not long term and multiple RSV infections can occur within the same year.
Eligible infants can receive nirsevimab as soon as practicable after RSV infection. Some specialists suggest waiting an interval of one month between infection and administering nirsevimab to maximise the duration of protection. Recent disease will provide a window of short-term protection and nirsevimab will provide protection for a further 6 months.
There are no concerns for safety or efficacy when administering nirsevimab to infants who have had previous RSV infection.
Which is safer, the maternal vaccine or the monoclonal antibody?
Both the maternal vaccine Abrysvo and the monoclonal antibody Nirsevimab are safe and effective at preventing severe RSV infections in infants.
Common side effects following either product include pain, redness and swelling at the injection site.
Fatigue has also been reported in pregnant people receiving Abrysvo. Maternal vaccination is not recommended before 28 weeks’ gestation.
In clinical trials a small number of infants (1 in 100) developed a mild rash after receiving Nirsevimab.
Please refer to Laemmle-Ruff I & Crawford N. Respiratory syncytial virus prevention is finally here: An overview of safety, AJGP. 2025;53(10).doi:10.31128/AJGP-06-24-7314 for more information.
Which is more effective, the monoclonal antibody and the maternal vaccine?
Nirsevimab (monoclonal antibody) and Abrysvo (RSV maternal vaccine) are both effective in preventing severe RSV infection in infants less than 8 months of age. There have been no clinical trials comparing efficacy of the 2 products.
Are there any concerns if a baby inadvertently receives the monoclonal antibody and their mother was vaccinated during pregnancy (>2 weeks before delivery)?
For most infants, only one RSV prevention strategy will be required for adequate protection, maternal vaccination or monoclonal antibody. Only a very small number of infants will require both. There are no safety concerns if an infant receives the monoclonal antibody and their mother was vaccinated during pregnancy.
Where unnecessary inadvertent administration occurs, it is important that the affected person be informed of the error using the open disclosure pathway. Administration errors should be reported to the jurisdiction’s vaccine safety service.
What is the recommendation if Abrysvo is inadvertently administered to a pregnant person earlier than 28 weeks?
If Abrysvo is administered to a pregnant person prior to 28 weeks’ gestation, the vaccinee should be informed of the error via an open disclosure discussion. The error should also be reported to the jurisdiction’s vaccine safety service.
Available data on the administration of Abrysvo between 24 and 27 weeks’ gestation has shown no safety concerns, and the vaccine is registered by the TGA from 24 weeks’ gestation.
For further guidance on managing RSV administration errors refer to: NCIRS clinical guidance on RSV immunisation product administration errors.
Can Arexvy be given in pregnancy as an alternative to Abrysvo?
No. Arexvy is not registered for use in pregnancy. There is limited safety data on the administration of Arexvy to pregnant people. It is currently only registered for adults 60 years of age and over. Should inadvertent administration occur the vaccinee should be informed using the open disclosure process. The jurisdiction’s vaccine safety service should be contacted for guidance.
Can Nirsevimab be purchased privately for those who fall outside of the funding criteria?
Supply of Nirsevimab was limited to a small number of state-funded vaccine programs in 2024. Nirsevimab is not currently available for private purchase.
Are non-Medicare card holders eligible for maternal vaccination/monoclonal antibody?
The RSV-MIPP is funded for Medicare card holders only. Abrysvo (maternal vaccination) can be purchased privately for those who do not qualify for funded vaccines. Nirsevimab is not currently available for private purchase.
Resources
- Australian Immunisation Handbook: Respiratory syncytial virus (RSV)
- Raising Children Net: Respiratory syncytial virus (RSV) in babies, children and teenagers
- Raising Children Net: Immunisation: pregnancy and breastfeeding
- RCH Kids health Information: Respiratory syncytial virus
- Immunisation Foundation of Australia: Unite Against RSV
- Australian Government Department of Health and Aged Care: When to get vaccinated – Immunisation for pregnancy
- NCIRS clinical guidance on RSV immunisation product administration errors
- NCIRS: Respiratory Syncytial Virus (RSV): Frequently asked questions (FAQs)
- View-hub by IVAC: Respiratory Syncytial Virus (RSV): Prevention Strategies and Product Introduction
- McNab S, Ha Do LA, Clifford V, et al. Changing Epidemiology of Respiratory Syncytial Virus in Australia – Delayed Re-emergence in Victoria Compared to Western Australia/New South Wales (WA/NSW) After Prolonged Lockdown for Coronavirus Disease 2019 (COVID-19). Clin Infect Dis. 2021;73(12):2365-2366. doi:10.1093/cid/ciab240
- Crawford N, Alafaci A, Clark J, et al. Study of Children Aged Under 2 Years Admitted With RSV at Four Australian Hospitals [2021-2022], J Paediatr Child Health. 2025; 0:1-9. doi:10.1111/jpc.16796
- Carcione D, Spencer P, Pettigre G, et al. Active port-marketing safety surveillance of Nirsevimab administered to children in Western Australia, April-July 2024, The Pediatric Infectious Diseases Journal. 2025. doi:10.1097/INF.0000000000004715
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: May 2026
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.