SEASONAL INFLUENZA IN POLAND– 2025/2026 SEASON EPIDEMIOLOGY, COMPLICATIONS, TREATMENT – LITERATURE REVIEW

Authors

DOI:

https://doi.org/10.31435/ijitss.2(50).2026.6046

Keywords:

Seasonal Flu, Poland, 2025/2026, Vaccinations, Antiviral Treatment, Complications

Abstract

Seasonal influenza caused by the influenza virus remains an important respiratory disease in the world. The World Health Organization (WHO) estimates that seasonal influenza causes about a billion infections per year, including 3-5 million severe cases and 290,000-650,000 deaths from respiratory causes. The 2025/2026 season in Europe started early: by mid-December 2025, WHO Europe was reporting intense influenza activity in more than half of the reporting countries and indicating the K subset of virus A (H3N2) as the main transmission factor in the general population. In Poland, official communications from the Chief Sanitary Inspectorate (GIS) similarly described an early acceleration of the disease, especially among children, without evidence of unusual virulence or clinically significant resistance to oseltamivir. The highest age-specific peaks were recorded among children aged 0-4 years (1,746.4 per 100,000) and 5-9 years (1,464.1 per 100,000). Vaccination coverage improved: the same official data export recorded 2,305,395 vaccinations against influenza in the 2025/2026 season to April 2026, compared to 1,805,695 in the 2024/2025 season. Current literature confirms that influenza is not just a self-limiting upper respiratory tract infection; It is associated with bacterial pneumonia, cardiovascular events, neurological complications and decompensation of chronic diseases. Modern management should therefore combine annual vaccinations, early diagnosis of complications, timely antiviral treatment in hospitalized, severe or progressive patients or those belonging to high-risk groups, as well as rational antibiotic therapy.

References

World Health Organization. (2025). Influenza (seasonal). https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal)

World Health Organization Regional Office for Europe. (2025, December 17). More than half of WHO European Region experiencing intense, early influenza season driven by new strain. https://www.who.int/europe/news/item/17-12-2025-more-than-half-of-who-european-region-experiencing-intense--early-influenza-season-driven-by-new-strain

Ministerstwo Zdrowia, Centrum e-Zdrowia, & Glowny Inspektorat Sanitarny. (2026, April 26). Raport o chorobach zakaznych. https://www.gov.pl/web/zdrowie/raport-o-chorobach-zakaznych

Glowny Inspektorat Sanitarny. (2026, February 9). Komunikat Glownego Inspektoratu Sanitarnego dotyczacy aktualnej sytuacji w zakresie infekcji sezonowych. Gov.pl. https://www.gov.pl/web/psse-otwock/komunikat-glownego-inspektoratu-sanitarnego

Glowny Inspektorat Sanitarny. (2025, December 23). Aktualne trendy zachorowan na infekcje sezonowe i szczepienia noworodkow przeciw gruzlicy. Gov.pl. https://www.gov.pl/web/psse-swidwin/aktualne-trendy-zachorowan-na-infekcje-sezonowe-i-szczepienia-noworodkow-przeciw-gruzlicy

Wojewodzka Stacja Sanitarno-Epidemiologiczna w Lodzi. (2026, May 5). Informacja dotyczaca zachorowan na grype, zakazen RSV i zakazen SARS-CoV-2 oraz prowadzonego nadzoru sentinel, 16.04.2026–30.04.2026. Gov.pl. https://www.gov.pl/web/wsse-lodz/informacja-dotyczaca-zachorowan-na-grype-zakazen-wirusem-rsv-i-zakazen-koronawirusem-sars-cov-2-oraz-prowadzonego-nadzoru-sentinel-16042026---30042026

World Health Organization. (2026, April 23). Global respiratory virus activity: Weekly update No. 574, week ending 12 Apr 2026. https://www.who.int/publications/m/item/global-respiratory-virus-activity-weekly-update

Centers for Disease Control and Prevention. (2026). Weekly U.S. influenza surveillance report: Key updates for week 16, ending 25 Apr 2026. https://www.cdc.gov/fluview/surveillance/2026-week-16.html

World Health Organization. (2025). Recommended composition of influenza virus vaccines for use in the 2025–2026 northern hemisphere influenza season. https://www.who.int/publications/m/item/recommended-composition-of-influenza-virus-vaccines-for-use-in-the-2025-2026-nh-influenza-season

Narodowy Instytut Zdrowia Publicznego PZH - PIB. (n.d.). Jak prowadzone sa szczepienia przeciw grypie w sezonie 2025/2026? Szczepienia.Info. https://szczepienia.pzh.gov.pl/faq/jak-prowadzone-sa-szczepienia-przeciw-grypie-w-sezonie-2025-2026/

Narodowy Instytut Zdrowia Publicznego PZH - PIB. (n.d.). Jak refundowane sa szczepionki przeciw grypie w sezonie 2025/2026? Szczepienia.Info. https://szczepienia.pzh.gov.pl/faq/jak-sa-refundowane-szczepionki-przeciw-grypie-w-sezonie-2023-2024/

World Health Organization. (2024, September 12). Clinical practice guidelines for influenza. https://www.who.int/publications/i/item/9789240097759

Centers for Disease Control and Prevention. (2026). Influenza antiviral medications: Summary for clinicians. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html

European Centre for Disease Prevention and Control. (2025, December 19). Early estimates show seasonal influenza vaccine protects against circulating A(H3N2) subclade K viruses. https://www.ecdc.europa.eu/en/news-events/early-estimates-show-seasonal-influenza-vaccine-protects-against-circulating-ah3n2

Lucaccioni, H., Marques, D. F., Kirsebom, F., Emborg, H. D., Hamilton, M., Whitaker, H., Bolt Botnen, A., Bucholc, M., Pozo, F., Andrews, N., Trebbien, R., Hameed, S. S., Lauenborg Møller, K., O'Doherty, M. G., Lopez-Bernal, J., Morrison, K., Cottrell, S., Wilton, S., Rose, A. M., … European IVE Group. (2026). Influenza vaccine effectiveness from nine studies during drifted A(H3N2) subclade K predominance, Europe, September 2025 to January 2026. Eurosurveillance, 31(7), 2600109. https://doi.org/10.2807/1560-7917.ES.2026.31.7.2600109

Kirsebom, F. C., Thompson, C., Talts, T., Kele, B., Whitaker, H. J., Andrews, N., Abdul Aziz, N., Rawlinson, C., Green, R. E., Quinot, C., Gardner, N., Waller, E., Allen, A., Watson, C. H., McDonald, S. L., Zambon, M., Pebody, R., Ramsay, M., Hoschler, K., … Lopez Bernal, J. (2025). Early influenza virus characterisation and vaccine effectiveness in England in autumn 2025, a period dominated by influenza A(H3N2) subclade K. Eurosurveillance, 30(46), 2500854. https://doi.org/10.2807/1560-7917.ES.2025.30.46.2500854

Centers for Disease Control and Prevention. (2026). Interim estimates of 2025–26 seasonal influenza vaccine effectiveness—United States. MMWR Morbidity and Mortality Weekly Report.

Qiao, M., Moyes, G., Zhu, F., Li, Y., & Wang, X. (2023). The prevalence of influenza bacterial co-infection and its role in disease severity: A systematic review and meta-analysis. Journal of Global Health, 13, 04063. https://doi.org/10.7189/jogh.13.04063

Ouranos, K., Vassilopoulos, S., Vassilopoulos, A., Shehadeh, F., & Mylonakis, E. (2024). Cumulative incidence and mortality rate of cardiovascular complications due to laboratory-confirmed influenza virus infection: A systematic review and meta-analysis. Reviews in Medical Virology, 34(1), e2497. https://doi.org/10.1002/rmv.2497

Kwong, J. C., Schwartz, K. L., Campitelli, M. A., Chung, H., Crowcroft, N. S., Karnauchow, T., Katz, K., Ko, D. T., McGeer, A. J., McNally, D., Richardson, D. C., Rosella, L. C., Simor, A., Smieja, M., Zahariadis, G., & Gubbay, J. B. (2018). Acute myocardial infarction after laboratory-confirmed influenza infection. The New England Journal of Medicine, 378(4), 345–353. https://doi.org/10.1056/NEJMoa1702090

Savagner, J., Trémeaux, P., Baudou, E., Mansuy, J. M., & Cheuret, E. (2024). Neurological involvement related to the influenza virus in children: A 5-year single-centre retrospective study. European Journal of Paediatric Neurology, 51, 100–109. https://doi.org/10.1016/j.ejpn.2024.05.012

Centers for Disease Control and Prevention. (2025). Influenza-associated encephalopathy and acute necrotizing encephalopathy among children—United States, 2024–25 influenza season. MMWR Morbidity and Mortality Weekly Report.

Influenza-Associated Acute Necrotizing Encephalopathy (IA-ANE) Working Group, Silverman, A., Walsh, R., Santoro, J. D., Thomas, K., Ballinger, E., Fisher, K. S., Thomas, A. X., Appavu, B., Kruer, M. C., Neilson, D., Knoll, J., Sharp, A. N., Edelman, H. E., Otallah, S., Morgan, A., Grzezulkowska, A., Nguyen, J., Rao, L. M., … Wilson-Murphy, M. (2025). Influenza-associated acute necrotizing encephalopathy in US children. JAMA, 334(8), 692–701. https://doi.org/10.1001/jama.2025.11534

BMC Pediatrics. (2024). Neurological complications associated with influenza in children: Recent evidence and clinical implications. BMC Pediatrics.

Behrouzi, B., Bhatt, D. L., Cannon, C. P., Vardeny, O., Lee, D. S., Solomon, S. D., & Udell, J. A. (2022). Association of influenza vaccination with cardiovascular risk: A meta-analysis. JAMA Network Open, 5(4), e228873. https://doi.org/10.1001/jamanetworkopen.2022.8873

Omidi, F., Zangiabadian, M., Shahidi Bonjar, A. H., Nasiri, M. J., & Sarmastzadeh, T. (2023). Influenza vaccination and major cardiovascular risk: A systematic review and meta-analysis of clinical trials studies. Scientific Reports, 13(1), 20235. https://doi.org/10.1038/s41598-023-47690-9

Hussain, S., Meijer, A., Govorkova, E. A., Dapat, C., Gubareva, L. V., Barr, I. G., Brown, S. K., Daniels, R. S., Fujisaki, S., Galiano, M., Huang, W., Kondor, R. J., Lackenby, A., Lewis, N., Lo, J., Nguyen, H. T., Patel, M. C., Pereyaslov, D., Rattigan, A., … Takashita, E. (2025). Global update on the susceptibilities of influenza viruses to neuraminidase inhibitors and the cap-dependent endonuclease inhibitor baloxavir, 2020–2023. Antiviral Research, 241, 106217. https://doi.org/10.1016/j.antiviral.2025.106217

Patel, M. C., Nguyen, H. T., Pascua, P. N. Q., Gao, R., Steel, J., Kondor, R. J., & Gubareva, L. V. (2024). Multicountry spread of influenza A(H1N1)pdm09 viruses with reduced oseltamivir inhibition, May 2023–February 2024. Emerging Infectious Diseases, 30(7), 1410–1415. https://doi.org/10.3201/eid3007.240480

Huang, C. H., Chen, M. T., & Tsai, M. H. (2026). Comparison of clinical outcomes of oseltamivir vs baloxavir in outpatients with influenza: A retrospective cohort analysis. International Journal of Infectious Diseases, 163, 108277. https://doi.org/10.1016/j.ijid.2025.108277

Centers for Disease Control and Prevention. (2026). Influenza antiviral drug resistance. https://www.cdc.gov/flu/treatment/antiviralresistance.html

Iuliano, A. D., Roguski, K. M., Chang, H. H., Muscatello, D. J., Palekar, R., Tempia, S., Cohen, C., Gran, J. M., Schanzer, D., Cowling, B. J., Wu, P., Kyncl, J., Ang, L. W., Park, M., Redlberger-Fritz, M., Yu, H., Espenhain, L., Krishnan, A., Emukule, G., … Global Seasonal Influenza-associated Mortality Collaborator Network. (2018). Estimates of global seasonal influenza-associated respiratory mortality: A modelling study. The Lancet, 391(10127), 1285–1300. https://doi.org/10.1016/S0140-6736(17)33293-2

GBD 2017 Influenza Collaborators. (2019). Mortality, morbidity, and hospitalisations due to influenza lower respiratory tract infections, 2017: An analysis for the Global Burden of Disease Study 2017. The Lancet Respiratory Medicine, 7(1), 69–89. https://doi.org/10.1016/S2213-2600(18)30496-X

World Health Organization. (2019). Global influenza strategy 2019–2030. https://www.who.int/publications/i/item/9789241515320

European Centre for Disease Prevention and Control. (2025, November 20). Rapid risk assessment—Assessing the risk of influenza for the EU/EEA in the context of increasing circulation of A(H3N2) subclade K. https://www.ecdc.europa.eu/en/publications-data/threat-assessment-brief-assessing-risk-influenza-november-2025

European Centre for Disease Prevention and Control. (2026). Surveillance for seasonal influenza. https://www.ecdc.europa.eu/en/seasonal-influenza/surveillance-reports-and-disease-data

European Medicines Agency. (2025). EU recommendations for 2025/2026 seasonal flu vaccine composition. https://www.ema.europa.eu/en/news/eu-recommendations-2025-2026-seasonal-flu-vaccine-composition

Narodowy Instytut Zdrowia Publicznego PZH - PIB, & Glowny Inspektorat Sanitarny. (2026). Choroby zakazne i zatrucia w Polsce w 2026 r.: Meldunki epidemiologiczne. https://wwwold.pzh.gov.pl/oldpage/epimeld/2026/index_mp.html

Narodowy Instytut Zdrowia Publicznego PZH - PIB. (2025). Jaki bedzie sklad szczepionek przeciw grypie w sezonie 2025/2026? Szczepienia.Info. https://szczepienia.pzh.gov.pl/jaki-bedzie-sklad-szczepionek-przeciw-grypie-w-sezonie-2025-2026/

Grohskopf, L. A., Blanton, L. H., Ferdinands, J. M., Reed, C., Dugan, V. G., & Daskalakis, D. C. (2025). Prevention and control of seasonal influenza with vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2025–26 influenza season. MMWR Morbidity and Mortality Weekly Report, 74(32), 500–507. https://doi.org/10.15585/mmwr.mm7432a2

Maloney, P., Reeves, E. L., Wielgosz, K., Price, A. M., Natarajan, K., DeSilva, M. B., Dascomb, K., Klein, N. P., Tartof, S. Y., Irving, S. A., Grannis, S. J., Ong, T. C., Weber, Z. A., Schuster, J. E., Zerr, D. M., Michaels, M. G., Boom, J. A., Halasa, N. B., Staat, M. A., … CDC Influenza Vaccine Effectiveness Collaborators. (2026). Interim estimates of 2025–26 seasonal influenza vaccine effectiveness—United States, September 2025–February 2026. MMWR Morbidity and Mortality Weekly Report, 75(9), 116–123. https://doi.org/10.15585/mmwr.mm7509a2

Mertz, D., Kim, T. H., Johnstone, J., Lam, P. P., Science, M., Kuster, S. P., Fadel, S. A., Tran, D., Fernandez, E., Bhatnagar, N., & Loeb, M. (2013). Populations at risk for severe or complicated influenza illness: Systematic review and meta-analysis. BMJ, 347, f5061. https://doi.org/10.1136/bmj.f5061

Uyeki, T. M., Bernstein, H. H., Bradley, J. S., Englund, J. A., File, T. M., Fry, A. M., Gravenstein, S., Hayden, F. G., Harper, S. A., Hirshon, J. M., Ison, M. G., Johnston, B. L., Knight, S. L., McGeer, A., Riley, L. E., Wolfe, C. R., Alexander, P. E., & Pavia, A. T. (2019). Clinical practice guidelines by the Infectious Diseases Society of America: 2018 update on diagnosis, treatment, chemoprophylaxis, and institutional outbreak management of seasonal influenza. Clinical Infectious Diseases, 68(6), 895–902. https://doi.org/10.1093/cid/ciy874

Dobson, J., Whitley, R. J., Pocock, S., & Monto, A. S. (2015). Oseltamivir treatment for influenza in adults: A meta-analysis of randomised controlled trials. The Lancet, 385(9979), 1729–1737. https://doi.org/10.1016/S0140-6736(14)62449-1

Hanula, R., Bortolussi-Courval, É., Mendel, A., Ward, B. J., Lee, T. C., & McDonald, E. G. (2024). Evaluation of oseltamivir used to prevent hospitalization in outpatients with influenza: A systematic review and meta-analysis. JAMA Internal Medicine, 184(1), 18–27. https://doi.org/10.1001/jamainternmed.2023.0699

Jefferson, T., Jones, M. A., Doshi, P., Del Mar, C. B., Hama, R., Thompson, M. J., Spencer, E. A., Onakpoya, I., Mahtani, K. R., Nunan, D., Howick, J., & Heneghan, C. J. (2014). Neuraminidase inhibitors for preventing and treating influenza in adults and children. Cochrane Database of Systematic Reviews, 2014(4), CD008965. https://doi.org/10.1002/14651858.CD008965.pub4

Hayden, F. G., Sugaya, N., Hirotsu, N., Lee, N., de Jong, M. D., Hurt, A. C., Ishida, T., Sekino, H., Yamada, K., Portsmouth, S., Kawaguchi, K., Shishido, T., Arai, M., Tsuchiya, K., Uehara, T., Watanabe, A., & Baloxavir Marboxil Investigators Group. (2018). Baloxavir marboxil for uncomplicated influenza in adults and adolescents. The New England Journal of Medicine, 379(10), 913–923. https://doi.org/10.1056/NEJMoa1716197

Ison, M. G., Portsmouth, S., Yoshida, Y., Shishido, T., Mitchener, M., Tsuchiya, K., Uehara, T., & Hayden, F. G. (2020). Early treatment with baloxavir marboxil in high-risk adolescent and adult outpatients with uncomplicated influenza (CAPSTONE-2): A randomised, placebo-controlled, phase 3 trial. The Lancet Infectious Diseases, 20(10), 1204–1214. https://doi.org/10.1016/S1473-3099(20)30004-9

Kumar, D., Ison, M. G., Mira, J. P., Welte, T., Hwan Ha, J., Hui, D. S., Zhong, N., Saito, T., Katugampola, L., Collinson, N., Williams, S., Wildum, S., Ackrill, A., Clinch, B., & Lee, N. (2022). Combining baloxavir marboxil with standard-of-care neuraminidase inhibitor in patients hospitalised with severe influenza (FLAGSTONE): A randomised, parallel-group, double-blind, placebo-controlled, superiority trial. The Lancet Infectious Diseases, 22(5), 718–730. https://doi.org/10.1016/S1473-3099(21)00469-2

Radovanovic, M., Petrovic, M., Barsoum, M. K., Nordstrom, C. W., Calvin, A. D., Dumic, I., Jevtic, D., & Hanna, R. D. (2022). Influenza myopericarditis and pericarditis: A literature review. Journal of Clinical Medicine, 11(14), 4123. https://doi.org/10.3390/jcm11144123

Fazal, A., Harker, E. J., Neelam, V., Olson, S. M., Rolfes, M. A., Reinhart, K., Kniss, K., Frutos, A., Leonard, J., Reed, C., Dugan, V. G., Safi, H., Dulski, T. M., Stanley-Downs, A., Bhatti, A., Armistead, I., Rao, S., Torres-Diaz, C., Thomas, A., … CDC Influenza-Associated Encephalopathy Collaborators. (2025). Pediatric influenza-associated encephalopathy and acute necrotizing encephalopathy—United States, 2024–25 influenza season. MMWR Morbidity and Mortality Weekly Report, 74(36), 556–564. https://doi.org/10.15585/mmwr.mm7436a1

Influenza-Associated Acute Necrotizing Encephalopathy (IA-ANE) Working Group, Silverman, A., Walsh, R., Santoro, J. D., Thomas, K., Ballinger, E., Fisher, K. S., Thomas, A. X., Appavu, B., Kruer, M. C., Neilson, D., Knoll, J., Sharp, A. N., Edelman, H. E., Otallah, S., Morgan, A., Grzezulkowska, A., Nguyen, J., Rao, L. M., … Wilson-Murphy, M. (2025). Influenza-associated acute necrotizing encephalopathy in US children. JAMA, 334(8), 692–701. https://doi.org/10.1001/jama.2025.11534

Jones-Gray, E., Robinson, E. J., Kucharski, A. J., Fox, A., & Sullivan, S. G. (2023). Does repeated influenza vaccination attenuate effectiveness? A systematic review and meta-analysis. The Lancet Respiratory Medicine, 11(1), 27–44. https://doi.org/10.1016/S2213-2600(22)00266-1

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2026-06-30

How to Cite

Zaborowski, M., Purgal-Zaborowska, K., Michalowska, K., Kolanowski, O., Winkler, M., Arczewska, A., Bezak, J., Turzanska, O., & Rataj, J. (2026). SEASONAL INFLUENZA IN POLAND– 2025/2026 SEASON EPIDEMIOLOGY, COMPLICATIONS, TREATMENT – LITERATURE REVIEW. International Journal of Innovative Technologies in Social Science, 5(2(50). https://doi.org/10.31435/ijitss.2(50).2026.6046

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