tetano
Editor, Senior Moderator
Influenza Other Respir Viruses
. 2025 Nov;19(12):e70194.
doi: 10.1111/irv.70194. Effectiveness of Influenza Vaccines and Duration of Protection Against Hospitalisation in England: 2022/2023 and 2023/2024 Seasons
Heather J Whitaker[SUP] 1 [/SUP], Freja C M Kirsebom[SUP] 2 [/SUP], Katie Hassell[SUP] 2 [/SUP], Catherine Quinot[SUP] 2 [/SUP], Julia Stowe[SUP] 2 [/SUP], Katja Hoschler[SUP] 3 [/SUP], Maria Zambon[SUP] 3 [/SUP], Nick J Andrews[SUP] 1 2 [/SUP], Conall H Watson[SUP] 2 [/SUP], Jamie Lopez Bernal[SUP] 2 [/SUP]
Affiliations
Background: Linkage of national, healthcare data can provide greater resolution of vaccine effectiveness (VE) against influenza subtypes, as well as the relative effectiveness of different vaccine types and the effects of waning on VE. We present 2022/2023 and 2023/2024 end-of-season VE against hospitalisation with laboratory confirmed influenza for England.
Methods: A test-negative design was used to estimate VE against hospitalisation. Cases and controls were identified within national laboratory surveillance systems and linked to hospital admission data. Vaccine histories were obtained from England's vaccine register. We combined results on VE by vaccine type over the two seasons using a meta-analysis.
Results: One hundred thousand five hundred eighty-one (28,565 positive) and 113,494 (21,243 positive) samples were eligible for inclusion in 2022/2023 and 2023/2024, respectively. The overall VE for children aged 2-17 years was 67% (95% CI, 63%-70%) in 2022/2023 and 56% (95% CI, 51%-60%) in 2023/2024. For adults aged 18-64, VE was 34% (95% CI, 30%-38%) in 2022/2023 and 38% (95% CI, 34%-42%) in 2023/2024. For adults aged 65+ years, VE was 25% (95% CI, 21%-29%) in 2022/2023 and 18% (95% CI, 14%-22%) in 2023/2024. We found no significant difference in VE by vaccine type. We found evidence of reduced VE against influenza A in adults 9 weeks or more post vaccination compared with 2-8 weeks post vaccination.
Conclusions: Vaccine protection against influenza hospitalisation was seen in all age groups, with strong protection for children. Adult protection could be strengthened by vaccination closer to the time of expected influenza circulation. Linkage of routine healthcare data provided us with a sufficiently large data set to estimate differences in VE by vaccine type and timing after vaccination.
Keywords: adjuvanted influenza vaccine; cell‐based influenza vaccine; inactivated influenza vaccine; influenza; live attenuated influenza vaccine; recombinant influenza vaccine; test‐negative design; vaccine effectiveness.
. 2025 Nov;19(12):e70194.
doi: 10.1111/irv.70194. Effectiveness of Influenza Vaccines and Duration of Protection Against Hospitalisation in England: 2022/2023 and 2023/2024 Seasons
Heather J Whitaker[SUP] 1 [/SUP], Freja C M Kirsebom[SUP] 2 [/SUP], Katie Hassell[SUP] 2 [/SUP], Catherine Quinot[SUP] 2 [/SUP], Julia Stowe[SUP] 2 [/SUP], Katja Hoschler[SUP] 3 [/SUP], Maria Zambon[SUP] 3 [/SUP], Nick J Andrews[SUP] 1 2 [/SUP], Conall H Watson[SUP] 2 [/SUP], Jamie Lopez Bernal[SUP] 2 [/SUP]
Affiliations
- PMID: 41307445
- PMCID: PMC12658907
- DOI: 10.1111/irv.70194
Background: Linkage of national, healthcare data can provide greater resolution of vaccine effectiveness (VE) against influenza subtypes, as well as the relative effectiveness of different vaccine types and the effects of waning on VE. We present 2022/2023 and 2023/2024 end-of-season VE against hospitalisation with laboratory confirmed influenza for England.
Methods: A test-negative design was used to estimate VE against hospitalisation. Cases and controls were identified within national laboratory surveillance systems and linked to hospital admission data. Vaccine histories were obtained from England's vaccine register. We combined results on VE by vaccine type over the two seasons using a meta-analysis.
Results: One hundred thousand five hundred eighty-one (28,565 positive) and 113,494 (21,243 positive) samples were eligible for inclusion in 2022/2023 and 2023/2024, respectively. The overall VE for children aged 2-17 years was 67% (95% CI, 63%-70%) in 2022/2023 and 56% (95% CI, 51%-60%) in 2023/2024. For adults aged 18-64, VE was 34% (95% CI, 30%-38%) in 2022/2023 and 38% (95% CI, 34%-42%) in 2023/2024. For adults aged 65+ years, VE was 25% (95% CI, 21%-29%) in 2022/2023 and 18% (95% CI, 14%-22%) in 2023/2024. We found no significant difference in VE by vaccine type. We found evidence of reduced VE against influenza A in adults 9 weeks or more post vaccination compared with 2-8 weeks post vaccination.
Conclusions: Vaccine protection against influenza hospitalisation was seen in all age groups, with strong protection for children. Adult protection could be strengthened by vaccination closer to the time of expected influenza circulation. Linkage of routine healthcare data provided us with a sufficiently large data set to estimate differences in VE by vaccine type and timing after vaccination.
Keywords: adjuvanted influenza vaccine; cell‐based influenza vaccine; inactivated influenza vaccine; influenza; live attenuated influenza vaccine; recombinant influenza vaccine; test‐negative design; vaccine effectiveness.