News release

From: The Kids Research Institute Australia

Australia's RSV Maternal and Infant Protection Program is delivering strong protection for babies, with new research from The Kids Research Institute Australia showing RSV vaccination given during pregnancy reduces the risk of RSV-related hospitalisation by more than 80 per cent during an infant's first six months of life.

Published today in JAMA Pediatrics, the findings come from the STREETON (STudy of Real world vaccinE Effectiveness of maTernal RSVpreF vaccinatiON against respiratory syncytial virus in hospitalised infants in Australia) study, one of the largest national evaluations of maternal RSV vaccination since the vaccine was introduced under the National Immunisation Program in early 2025.

The analyses included 1,012 infants hospitalised with Acute Respiratory Illness (ARI) across nine Australian hospitals. The results showed that RSV vaccination during pregnancy offered high and sustained protection against hospitalisation and severe forms of the respiratory diseases caused by RSV in infants through six months of age:

• 80.8 per cent effective at reducing RSV-related hospitalisations,
• 77.8 per cent effective at reducing hospitalisations for RSV-related lower respiratory tract disease, and
• 80.4 per cent effective at reducing hospitalisations for severe RSV-related lower respiratory tract disease.

Protection was highest during the earliest months of life, when babies are most vulnerable to serious RSV infection. In infants through to two months of age, vaccine effectiveness was 86.3 per cent against hospitalisations for RSV-related lower respiratory tract disease.

Importantly, protection remained consistently high regardless of when the vaccine was given during the recommended pregnancy window (from 28 weeks of gestational age) or whether it was administered alongside other routine maternal vaccines, supporting its addition into standard pregnancy care.

Clinician-scientist at the Wesfarmers Centre of Vaccines and Infectious Diseases, based at The Kids; paediatrician at Perth Children’s Hospital; and a Clinical Senior Lecturer at The University Of Western Australia’s Medical School, Dr Ushma Wadia said the results showed Australia's Maternal and Infant RSV Protection Program is doing exactly what it was designed to do – protecting young babies from serious RSV illness.

“This represents some of the strongest real-world evidence demonstrating that maternal RSV vaccination is working in Australia. Importantly, the findings show the vaccine can be effectively incorporated into routine antenatal care pathways, including alongside other recommended pregnancy vaccines, giving general practitioners, obstetricians, midwives and families confidence that we have an effective RSV prevention strategy to reduce the burden of severe RSV-related disease in our youngest babies," Dr Wadia said.

The findings build on The Kids Research Institute Australia’ internationally recognised RSV research and reinforce its standing as a leader in understanding and preventing RSV disease across Australia. In May,  research from The Kids Research Institute Australia demonstrated that Australia’s RSV Maternal and Infant Protection Program (RSV-MIPP) – combining maternal vaccination during pregnancy and immunisation for babies – cut hospital admissions for Australia’s youngest babies by almost half in its first year, providing strong early evidence of the program’s effectiveness.

Researchers will continue to evaluate vaccine effectiveness over time, with future analyses using larger sample sizes to evaluate protection across different infant subgroups, protection beyond six months of age and for infants born out of RSV season.

These findings will help guide ongoing efforts to protect babies from severe RSV disease.

The Kids Research Institute Australia wishes to acknowledge the valuable contributions of researchers from Curtin University, Monash University, Murdoch Children’s Research Institute, The University of Adelaide, The University of Melbourne, The University of New South Wales, The University of Queensland, The University of Sydney and The University of Western Australia, whose collective efforts supported this important national study. The STREETON Study also extends its thanks to the nine participating hospitals whose teams contributed data that made this research possible: Fiona Stanley Hospital, Monash Children’s Hospital, Perth Children’s Hospital, Queensland Children’s Hospital, Royal Children’s Hospital, Royal Darwin Hospital, Sydney Children’s Hospital, The Children’s Hospital at Westmead and The Women’s and Children’s Hospital Network.

The STREETON Study was funded by Pfizer through a collaborative grant to The Kids Research Institute Australia/University of Western Australia.