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. 2026 Apr 28:S0012-3692(26)00591-X.
doi: 10.1016/j.chest.2026.04.022. Online ahead of print.
In-hospital influenza vaccination is associated with reduced 1-year mortality in critical patients with chronic pulmonary disease: a real world target trial emulation
Jiadong Feng 1 , Fengchan Xi 2 , Chuanrui Sun 1 , Shanjun Tan 3 , Xiling Wang 4
Affiliations
Background: Influenza vaccination is widely recommended to prevent death and serious illness in vulnerable people, but in-hospital influenza vaccination for critically ill patients with chronic pulmonary disease (CPD) remains limited.
Research question: Is in-hospital influenza vaccination effective in improving the prognosis of critical patients with CPD?
Study design and methods: We designed a target trial emulation using critical inpatients with CPD from the MIMIC-IV database (2011-2022). Propensity score matching was employed to balance baseline characteristics. The primary effectiveness outcome was 1-year mortality, with fever within 7 days post-vaccination as an exploratory safety outcome. Associations with mortality were assessed using Cox and accelerated failure time models, while readmission or emergency department (ED) visits were assessed using logistic models. Vaccine effectiveness (VE) was estimated as (1-hazard ratio or odds ratio)*100, and the number needed to vaccinate (NNV) was derived. Non-inferiority for fever was defined as risk difference (RD) with upper 95% confidence interval (CI) < 5%.
Results: Among 7734 patients, 3803 (49.2%) received the influenza vaccine. Vaccination was associated with reduced 1-year mortality (VE 12%; 95% CI: 3%-20%), with NNV to prevent one death of 30 (95% CI: 18-119). Furthermore, vaccinated patients showed 12% (95% CI: 1%-21%) lower 90-day mortality, 13% (95% CI: 3%-22%) reduced readmission risk, and 23% (95% CI: 12%-32%) fewer ED visits. Non-inferiority in fever incidence was demonstrated for the vaccinated group compared with the unvaccinated group according to the pre-specified non-inferiority criterion (RD, 2.22%; 95% CI: -0.02%-4.47%).
Interpretation: In-hospital influenza vaccination is effective for critical patients with CPD, supporting its integration into routine inpatient care to improve long-term outcomes.
Keywords: Chronic pulmonary disease; In-hospital influenza vaccination; Intensive care unit; Target trial emulation.
. 2026 Apr 28:S0012-3692(26)00591-X.
doi: 10.1016/j.chest.2026.04.022. Online ahead of print.
In-hospital influenza vaccination is associated with reduced 1-year mortality in critical patients with chronic pulmonary disease: a real world target trial emulation
Jiadong Feng 1 , Fengchan Xi 2 , Chuanrui Sun 1 , Shanjun Tan 3 , Xiling Wang 4
Affiliations
- PMID: 42061701
- DOI: 10.1016/j.chest.2026.04.022
Background: Influenza vaccination is widely recommended to prevent death and serious illness in vulnerable people, but in-hospital influenza vaccination for critically ill patients with chronic pulmonary disease (CPD) remains limited.
Research question: Is in-hospital influenza vaccination effective in improving the prognosis of critical patients with CPD?
Study design and methods: We designed a target trial emulation using critical inpatients with CPD from the MIMIC-IV database (2011-2022). Propensity score matching was employed to balance baseline characteristics. The primary effectiveness outcome was 1-year mortality, with fever within 7 days post-vaccination as an exploratory safety outcome. Associations with mortality were assessed using Cox and accelerated failure time models, while readmission or emergency department (ED) visits were assessed using logistic models. Vaccine effectiveness (VE) was estimated as (1-hazard ratio or odds ratio)*100, and the number needed to vaccinate (NNV) was derived. Non-inferiority for fever was defined as risk difference (RD) with upper 95% confidence interval (CI) < 5%.
Results: Among 7734 patients, 3803 (49.2%) received the influenza vaccine. Vaccination was associated with reduced 1-year mortality (VE 12%; 95% CI: 3%-20%), with NNV to prevent one death of 30 (95% CI: 18-119). Furthermore, vaccinated patients showed 12% (95% CI: 1%-21%) lower 90-day mortality, 13% (95% CI: 3%-22%) reduced readmission risk, and 23% (95% CI: 12%-32%) fewer ED visits. Non-inferiority in fever incidence was demonstrated for the vaccinated group compared with the unvaccinated group according to the pre-specified non-inferiority criterion (RD, 2.22%; 95% CI: -0.02%-4.47%).
Interpretation: In-hospital influenza vaccination is effective for critical patients with CPD, supporting its integration into routine inpatient care to improve long-term outcomes.
Keywords: Chronic pulmonary disease; In-hospital influenza vaccination; Intensive care unit; Target trial emulation.