Nirsevimab provides age-specific protection against RSV hospitalisation in the first year of life: a population-level study in Queensland, Australia
DOI:
https://doi.org/10.33321/cdi.2026.50.066Keywords:
respiratory syncytial virus, RSV, nirsevimab, vaccine effectiveness, interrupted time-series, population-level impact, hospitalisation, age-specific protection, QueenslandAbstract
Nirsevimab, a long-acting monoclonal antibody with activity against respiratory syncytial virus (RSV), was introduced into the Queensland paediatric RSV prevention program in 2024. Using Queensland Notifiable Conditions Register (NoCS) data, we found that the infant cohort eligible for the nirsevimab program had lower RSV hospitalisation rates than comparable pre-program cohorts. The population-level impact of nirsevimab was greatest during the first month of life (incidence rate ratio [IRR]: 0.22; 95% confidence interval [95% CI]: 0.16–0.31; representing a 78% reduction in hospitalisation rate), with its magnitude gradually declining thereafter until nine months of age (IRR: 0.77; 95% CI: 0.62–0.96; a 23% reduction), following which the impact of nirsevimab on hospitalisation rate, with increasing age of the infant or child, was no longer statistically significant. An interrupted time-series analysis demonstrated an immediate 63% reduction in RSV hospitalisations following nirsevimab’s introduction (IRR: 0.37; 95% CI: 0.23–0.60), showing a substantial population-level impact of the program in Queensland, Australia.
Downloads
References
Li Y, Wang X, Blau DM, Caballero MT, Feikin DR, Gill CJ et al. Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in children younger than 5 years in 2019: a systematic analysis. Lancet. 2022;399(10340):2047–64. doi: https://doi.org/10.1016/S0140-6736(22)00478-0.
Self A, Van Buskirk J, Clark J, Cochrane JE, Knibbs L, Cass-Verco J et al. Respiratory syncytial virus disease morbidity in Australian infants aged 0 to 6 months: a systematic review with narrative synthesis. BMC Public Health. 2023;23(1):2560. doi: https://doi.org/10.1186/s12889-023-17474-x.
Queensland Government. Free RSV immunisation program launches today for newborn babies. [Media release.] Brisbane: Queensland Government; 15 April 2024. [Accessed on 1 September 2026.] Available from: https://statements.qld.gov.au/statements/100114.
El-Heneidy A, Grimwood K, Robson JM, Vilaylath CV, Cherian SG, Lambert SB et al. Impact of nirsevimab on respiratory syncytial virus PCR test positivity in young infants: a community-level observational study in Queensland, Australia. J Paediatr Child Health. 2026;62(4):614–20. doi: https://doi.org/10.1111/jpc.70317.
Roughan W, Cavanagh-Ochiai B, Barnekow D, Lottkowitz K, Schafer K, Camadoo L et al. Infant respiratory syncytial virus (RSV) immunisation coverage in an Australian regional area, 1 May 2024 – 31 October 2025. Commun Dis Intell (2018). 2026;50. doi: https://doi.org/10.33321/cdi.2026.50.031.
Queensland State Government Department of Health (Queensland Health). Queensland Paediatric Respiratory Syncytial Virus (RSV) Prevention Programme: Update and Programme Impact. Brisbane: Queensland Health Immunisation Unit; August 2025. [Accessed on 27 April 2026.] Available from: https://www.health.qld.gov.au/__data/assets/pdf_file/0027/1462590/qld-paediatric-rsv-impact-results.pdf.
Australian Technical Advisory Group on Immunisation (ATAGI). Neonates and infants aged <8 months whose mothers were not vaccinated at least 2 weeks before giving birth, or who are at increased risk of severe disease, are recommended to receive passive immunisation with a long-acting RSV-specific monoclonal antibody. [Media release.] Canberra: Australian Government Department of Health, Disability and Ageing, Australian Immunisation Handbook; 12 May 2026. [Accessed on 1 September 2026.] Available from: https://immunisationhandbook.health.gov.au/recommendations/neonates-and-infants-aged.
Morley C, Grimwood K, Maloney S, Ware RS. Meteorological factors and respiratory syncytial virus seasonality in subtropical Australia. Epidemiol Infect. 2018;146(6):757–62. doi: https://doi.org/10.1017/S0950268818000614.
Butler J, Gunnarsson R, Traves A, Marshall H. Severe respiratory syncytial virus infection in hospitalized children less than 3 years of age in a temperate and tropical climate. Pediatr Infect Dis J. 2019;38(1):6–11. doi: https://doi.org/10.1097/INF.0000000000002026.
Paynter S, Ware RS, Sly PD, Weinstein P, Williams G. Respiratory syncytial virus seasonality in tropical Australia. Aust N Z J Public Health. 2015;39(1):8–10. doi: https://doi.org/10.1111/1753-6405.12347.
Queensland Health. Notifiable conditions reports: technical notes. [Webpage.] Brisbane: Queensland Health; 30 April 2026. [Accessed on 9 September 2026.] Available from: https://www.health.qld.gov.au/clinical-practice/guidelines-procedures/diseases-infection/surveillance/reports/notifiable/technical-notes.
Queensland State Government. Open data portal. Births by month. [Webpage.] Brisbane: Queensland State Government; 2026. [Accessed on 17 March 2026.] Available from: https://www.data.qld.gov.au/dataset/births-by-month.
Hammitt LL, Dagan R, Yuan Y, Baca Cots M, Bosheva M, Madhi SA et al. Nirsevimab for prevention of RSV in healthy late-preterm and term infants. N Engl J Med. 2022;386(9):837–46. doi: https://doi.org/10.1056/NEJMoa2110275.
Wadia U, Moore HC, Richmond PC, Levy A, Bell L, Pienaar C et al. Effectiveness of nirsevimab in preventing RSV-hospitalisation among young children in Western Australia 2024. J Infect. 2025;90(4):106466. doi: https://doi.org/10.1016/j.jinf.2025.106466.
Blyth CC, Wadia U, Britton PN, Carr J, Clark JE, Crawford NW et al. Respiratory syncytial virus epidemiology and effectiveness of infant nirsevimab: 2024 results from the Australian Sentinel Hospital Network (FluCAN-PAEDS). Euro Surveill. 2026;31(2):2500275. doi: https://doi.org/10.2807/1560-7917.ES.2026.31.2.2500275.
Amin J, Ellis SL, Lambeth C, Gugushef J, Selvey C. Impact of the 2025 New South Wales respiratory syncytial virus prevention program on infant notifications and hospitalisations: a population-based analysis. Med J Aust. 2026;224(6):e70222. doi: https://doi.org/10.5694/mja2.70222.
Rice E, Oakes DB, Holland C, Moore HC, Blyth CC. Respiratory syncytial virus in children: epidemiology and clinical impact post-COVID-19. Curr Opin Infect Dis. (2023);36(6):522–8. doi: https://doi.org/10.1097/QCO.0000000000000967.
Australian Institute of Health and Welfare (AIHW). Admitted patient care 2023–24: data tables. [Webpage.] Canberra: AIHW2025. [Accessed on 1 July 2026.] Available from: https://www.aihw.gov.au/reports-data/myhospitals/sectors/admitted-patient-care.
Published
How to Cite
License
Copyright (c) 2026 Communicable Diseases Intelligence
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
