Report of the National Influenza Surveillance Scheme, 2022–2023
DOI:
https://doi.org/10.33321/cdi.2026.50.022Keywords:
influenza, surveillance, influenza-like-illness, sentinel surveillanceAbstract
This report describes influenza surveillance activities in Australia in 2022 to 2023. Data were extracted from several sources constituting the National Influenza Surveillance Scheme.
Following the relaxation of public health and social measures which had been applied in Australia in response to the coronavirus disease 2019 (COVID-19) pandemic in 2020 and 2021, the influenza seasons in 2022 and 2023 were characterised by high activity overall, with 1.4 and 1.8 times the number of laboratory-confirmed influenza notifications than those of the 2015–2019 pre-pandemic five-year mean, respectively. There were differences in the timing of the 2022 and 2023 influenza seasons compared to most pre-pandemic years, with earlier season starts and earlier peaks (approximately six to eight weeks earlier than in pre-pandemic years). There was also considerable variation in the timing of peak influenza activity between the states and territories, particularly in 2023. Notification rates were highest in the 5–9 years age group, with rates in this age group about two and a half times as high in 2022 and three times as high in 2023 as the overall notification rate in the corresponding years.
Influenza A(unsubtyped) comprised most notifications in 2022 and 2023. Of the remaining samples, influenza A(H3N2) was dominant in 2022; however, in 2023, there was substantial circulation of influenza B, which predominantly affected children and younger adults, and of A(H1N1).
Sentinel surveillance supports the assessment that both the 2022 and 2023 influenza seasons were characterised by early, high activity. High notification rates were also reflected in increased sentinel hospital admissions with confirmed influenza in 2023, particularly among children. The burden placed on sentinel hospitals due to people admitted with influenza was moderate in 2022 but high in 2023. Severity, measured through the proportion of patients admitted to sentinel hospital intensive care units, was moderate in both years and consistent with historical estimates. Influenza was recorded as the underlying cause of death in 0.16% of all deaths that occurred in 2022, and 0.24% of all deaths in 2023.
Overall, the 2022 influenza season had high activity with low-to-moderate severity, while 2023 had high activity with moderate severity.
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References
Paules C, Subbarao K. Influenza. Lancet. 2017;390(10095):697–708. doi: https://doi.org/10.1016/S0140-6736(17)30129-0.
World Health Organization (WHO). Influenza (seasonal). [Online fact sheet.] Geneva: WHO; 28 February 2025. Available from: https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal).
Communicable Diseases Epidemiology Surveillance Section. Report of the National Influenza Surveillance Scheme, 2011 to 2018. Commun Dis Intell (2018). 2022;46. doi: https://doi.org/10.33321/cdi.2022.46.12.
Hassall J, Kutzner L, Whitehead S, Tsang T, Hogarth F, St George S. Report of the National Influenza Surveillance Scheme, 2019. Commun Dis Intell (2018). 2026;50. doi: https://doi.org/10.33321/cdi.2026.50.020.
Bonacina F, Boëlle PY, Colizza V, Lopez O, Thomas M, Poletto C. Global patterns and drivers of influenza decline during the COVID-19 pandemic. Int J Infect Dis. 2023;128:132–9. doi: https://doi.org/10.1016/j.ijid.2022.12.042.
Bright A, Glynn-Robinson AJ, Kane S, Wright R, Saul N. The effect of COVID-19 public health measures on nationally notifiable diseases in Australia: preliminary analysis. Commun Dis Intell (2018). 2020;44. doi: https://doi.org/10.33321/cdi.2020.44.85.
Sullivan SG, Carlson S, Cheng AC, Chilver MB, Dwyer DE, Irwin M et al. Where has all the influenza gone? The impact of COVID-19 on the circulation of influenza and other respiratory viruses, Australia, March to September 2020. Euro Surveill. 2020;25(47):2001847. doi: https://doi.org/10.2807/1560-7917.ES.2020.25.47.2001847.
Whitehead S, Hassall J, Kutzner L, Tsang T, Singhal S. Report of the National Influenza Surveillance Scheme, 2020–2021. Commun Dis Intell (2018). 2026;50. doi: https://doi.org/10.33321/cdi.2026.50.021.
World Health Organization (WHO) Collaborating Centre for Reference and Research on Influenza (CCRRI). WHO GISRS Surveillance; WHO Global Influenza Surveillance and Response System (GISRS) Surveillance and Vaccine Development. [Webpage.] Melbourne: WHO CCRRI; 2025. Available from: http://www.influenzacentre.org/Centre_Activities_WHO_GISRS_Surveillance.html.
Kerr AG, Carlson SJ, Baldwin Z, Innes RJ, Howard ZL, Bennett M et al. FluTracking: Weekly online community-based surveillance of respiratory illness in Australia, 2020–2022 Report. Commun Dis Intell (2018). 2025;49. doi: https://doi.org/10.33321/cdi.2025.49.024.
Kerr A, Kerr S, Adams S, McKenzie T, Boettiger D, Dalton C. FluTracking: Weekly online community-based surveillance of respiratory illness in Australia, 2023 Report. Commun Dis Intell (2018). 2025;49. doi: https://doi.org/10.33321/cdi.2025.49.037.
Australian Technical Advisory Group on Immunisation (ATAGI). ATAGI advice on seasonal influenza vaccines in 2022. [Webpage.] Canberra: Australian Government Department of Health, Disability and Ageing; 25 March 2022. [Accessed on 19 May 2026.] Available from: https://www.health.gov.au/resources/publications/atagi-advice-on-seasonal-influenza-vaccines-in-2022.
ATAGI. ATAGI advice on seasonal influenza vaccines in 2023. [Webpage.] Canberra: Australian Government Department of Health, Disability and Ageing; 28 February 2023. [Accessed on 19 May 2026.] Available from: https://www.health.gov.au/resources/publications/atagi-advice-on-seasonal-influenza-vaccines-in-2023.
Chilver M, Stocks N. The Australian Sentinel Practices Research Network Annual Surveillance Report 2022. [Unpublished manuscript/report]. Adelaide: University of Adelaide, Australian Sentinel Practices Research Network (ASPREN); 2022.
Chilver M, Blakeley D, Ahsani Z, Stocks N. The Australian Sentinel Practices Research Network Annual Surveillance Report 2023. [Unpublished manuscript/report]. Adelaide: University of Adelaide, ASPREN; 2023.
Chilver M, Ahsani Z, Sullivan SG, Edwards J, Dueger E, Turra M et al. Evaluating the role of self-collected home swab data in enhancing influenza vaccine effectiveness estimates in general practice. Vaccine. 2026;69:127994. doi: https://doi.org/10.1016/j.vaccine.2025.127994.
Panatto D, Signori A, Lai PL, Gasparini R, Amicizia D. Heterogeneous estimates of influenza virus types A and B in the elderly: results of a meta-regression analysis. Influenza Other Respir Viruses. 2018;12(4):533–43. doi: https://doi.org/10.1111/irv.12550.
Skowronski DM, Chambers C, De Serres G, Sabaiduc S, Winter AL, Dickinson JA et al. Age-related differences in influenza B infection by lineage in a community-based sentinel system, 2010–2011 to 2015–2016, Canada. J Infect Dis. 2017;21(6):697–702. doi: https://doi.org/10.1093/infdis/jix393.
Cheng AC, Dwyer DE, Holmes M, Irving LB, Simpson G, Senanayake S et al. Influenza epidemiology in patients admitted to sentinel Australian hospitals in 2019: the Influenza Complications Alert Network (FluCAN). Commun Dis Intell (2018). 2022;46. doi: https://doi.org/10.33321/cdi.2022.46.14.
Australian Bureau of Statistics. Causes of Death, Australia. Reference period: 2023. [Webpage]. Canberra: Australian Bureau of Statistics; 10 October 2024. Available from: https://www.abs.gov.au/statistics/health/causes-death/causes-death-australia/2023.
Andrews K, Morrison S, Hunt G, Tehan D. Reopening to tourists and other international travellers to secure our economic recovery. [Media statement.] Canberra: Australian Government, Home Affairs portfolio; 7 February 2022. Available from: https://minister.homeaffairs.gov.au/KarenAndrews/Pages/reopening-to-tourists-and-other-international-travellers-to-secure-our-economic-recovery.aspx.
Chen L, Guo Y, López-Güell K, Ma J, Dong Y, Xie J et al. Immunity debt for seasonal influenza after the COVID-19 pandemic and as a result of nonpharmaceutical interventions: an ecological analysis and cohort study. Adv Sci (Weinh). 2025;12(20):e2410513. doi: https://doi.org/10.1002/advs.202410513.
National Centre for Immunisation Research and Surveillance (NCIRS). All persons: 2020–2026 (YTD) influenza vaccination coverage, Australia. [Webpage.] Sydney: Sydney Children’s Hospitals Network, NCIRS; 2026. Available from: https://ncirs.org.au/influenza-vaccination-coverage-data/all-persons-2020-2026-ytd-influenza-vaccination-coverage.
Bardsley M, Morbey RA, Hughes HE, Beck CR, Watson CH, Zhao H et al. Epidemiology of respiratory syncytial virus in children younger than 5 years in England during the COVID-19 pandemic, measured by laboratory, clinical, and syndromic surveillance: a retrospective observational study. Lancet Infect Dis. 2023;23(1):56–66. doi: https://doi.org/10.1016/S1473-3099(22)00525-4.
WHO. Disease Outbreak News: Upsurge of respiratory illnesses among children – Northern China. [Media release.] Geneva: WHO; 23 November 2023. Available from: https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON494.
Therapeutic Goods Administration (TGA). Clinical performance evaluation and risk management of seasonal influenza rapid antigen tests. [Webpage.] Canberra: Australian Government Department of Health, Disability and Ageing, TGA; 1 March 2021. Available from: https://www.tga.gov.au/resources/guidance/clinical-performance-evaluation-and-risk-management-seasonal-influenza-rapid-antigen-tests.
Hirve S, Newman LP, Paget J, Azziz-Baumgartner E, Fitzner J, Bhat N et al. Influenza seasonality in the tropics and subtropics - when to vaccinate? PloS One. 2016;11(4):e0153003. doi: https://doi.org/10.1371/journal.pone.0153003.
Lu C, Barr IG, Lambert S, Mengersen K, Wang L, Yang W et al. Shifts in seasonal influenza patterns in Australia during and after COVID-19: a comprehensive analysis. J Infect Public Health. 2025;18(1):102620. doi: https://doi.org/10.1016/j.jiph.2024.102620.
Langer J, Welch VL, Moran MM, Cane A, Lopez SMC, Srivastava A et al. High clinical burden of influenza disease in adults aged ≥ 65 Years: can we do better? A systematic literature review. Adv Ther. 2023;40(4):1601–27. doi: https://doi.org/10.1007/s12325-023-02432-1.
Australian Bureau of Statistics. Household Impacts of COVID-19 Survey. Reference period: April 2022. [Webpage.] Canberra: Australian Bureau of Statistics; 17 May 2022. Available from: https://www.abs.gov.au/statistics/people/people-and-communities/household-impacts-covid-19-survey/apr-2022.
Caini S, Meijer A, Nunes MC, Henaff L, Zounon M, Boudewijns B et al. Probable extinction of influenza B/Yamagata and its public health implications: a systematic literature review and assessment of global surveillance databases. Lancet Microbe. 2024;5(8):100851. doi: https://doi.org/10.1016/S2666-5247(24)00066-1.
WHO. Recommended composition of influenza virus vaccines for use in the 2024 southern hemisphere influenza season. [Meeting report.] Geneva: WHO; 29 September 2023. Available from: https://www.who.int/publications/m/item/recommended-composition-of-influenza-virus-vaccines-for-use-in-the-2024-southern-hemisphere-influenza-season.
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