Jeffery, Caroline 
ORCID: 0000-0002-8023-0708, Cheyne, Christopher, Buchan, Iain ORCID: 0000-0003-3392-1650, Garcia-Finana, Marta ORCID: 0000-0003-4939-0575, Green, Mark A, Bonnett, Laura ORCID: 0000-0002-6981-9212, Hughes, David Michael ORCID: 0000-0002-1287-9994, French, Neil ORCID: 0000-0003-4814-8293 and Hungerford, Daniel ORCID: 0000-0002-9770-0163
(2025)
Effect of Influenza Vaccination on Post-Admission Outcomes for Influenza Patients in England: A Population-Based Cohort Study
[Preprint]
Abstract
Introduction In the UK, adults 65 years and over and those in clinical risk groups are among those eligible for seasonal influenza vaccination. While vaccination effectiveness for reducing cases of influenza is well documented, less is known about impact on wider hospital and post-discharge outcomes in the UK is lacking. We investigated whether vaccinated adults hospitalised with confirmed influenza infection had different outcomes to non-vaccinated adults during contact with health services. Methods A retrospective cohort study using the Combined Intelligence for Population Health Action platform, linking primary care, secondary care and laboratory data for Cheshire and Merseyside (2.7M population), UK. We accessed 2081 laboratory-confirmed influenza hospital admissions for adults ≥16 years (October 2018 - April 2024). We studied the association of influenza vaccination with several hospital and post-discharge outcomes, considering competing risks and potential confounding factors. We included age-based subgroup analyses. Results Vaccination uptake was recorded as 38.8%, 52.7%, 20.9% and 30.8% among ≥16, ≥65, 16-64 and 50-64 years respectively. Among the full cohort and ≥65 years cohort, vaccination was associated with a reduction in length of hospital stay in competing risk models (17%, 95%CI 7-25%; 19%, 95% CI 7-31%), risk of death in hospital or post-discharge (aHR 0.68, 95%CI 0.50-0.92; aHR 0.67, 95%CI 0.48-0.92) and change in vaccination status in the next season (aOR 0.19, 95%CI 0.13-0.27; aOR 0.07 95%CI 0.04-0.13). No statistically significant difference was detected for admission to critical care, hospital death, or post-discharge outcomes (death, readmission, attendance to general practice or emergency department). Conclusions Influenza vaccination was associated with benefits beyond acute illness, reducing length of hospital stay and mortality among adults hospitalised with laboratory-confirmed influenza. Findings support policy decisions, including greater outreach to high-risk, low-uptake groups and advocate for the national integration of laboratory data with comprehensive healthcare data to enable more robust vaccine evaluations.
| Item Type: | Preprint |
|---|---|
| Uncontrolled Keywords: | 4203 Health Services and Systems, 32 Biomedical and Clinical Sciences, 3202 Clinical Sciences, 42 Health Sciences, Infectious Diseases, Pneumonia & Influenza, Emerging Infectious Diseases, Health Services, Biodefense, Immunization, Influenza, Prevention, Clinical Research, Vaccine Related, Patient Safety, 6.1 Pharmaceuticals, 3.4 Vaccines, Infection, 3 Good Health and Well Being |
| Divisions: | Faculty of Health & Life Sciences Faculty of Health & Life Sciences > Inst. Infection, Vet & Ecological Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 17 Jul 2025 07:10 |
| Last Modified: | 14 Jan 2026 13:26 |
| DOI: | 10.2139/ssrn.5339382 |
| Open Access URL: | https://papers.ssrn.com/sol3/papers.cfm?abstract_i... |
| Related Websites: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3193749 |
| Disclaimer: | The University of Liverpool is not responsible for content contained on other websites from links within repository metadata. Please contact us if you notice anything that appears incorrect or inappropriate. |
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