Influenza Vaccination Status and Clinical Outcomes Among Adults Hospitalized with Community-Acquired Pneumonia: A Retrospective Cohort from Saudi Arabia
In brief
Vaccinated pneumonia patients had 1.8% ICU admissions versus 7.5% unvaccinated
Among 485 adults hospitalized with community-acquired pneumonia in Saudi Arabia, ICU admission was less common in vaccinated patients: 1.8% versus 7.5%. The retrospective study found no significant differences in confirmed influenza, hospital stay or in-hospital death, so the apparent reduction in severe illness is an association, not proof that vaccination caused it.
- Journal
- Vaccines (Q1)
- Published
- 14 September 2026
- Study design
- Retrospective cohort
- Evidence level
- Level 3, Low (CEBM 3b)
- Authors
- Shouq M Alzaaqi, Ayman Banjar, Majed A Almoghrabi, Seham F Basheer, Sami Alsaedi, Saeed M Algarni, et al.
- PMID
- 42797630
- DOI
- 10.3390/vaccines14090810
Why clinicians should know about it
- Picked for Family Practice (paper of the day, 29 September 2026): Influenza vaccination linked to ICU admission in CAP
Abstract
BACKGROUND: Influenza vaccination is widely recommended to prevent influenza and its complications; however, its association with clinical outcomes among high-risk populations remains uncertain. This study aimed to investigate the association between influenza vaccination status and clinical outcomes among adults hospitalized with community-acquired pneumonia (CAP) in Saudi Arabia. METHODS: This retrospective cohort study included adults hospitalized with CAP in Saudi public hospitals between October 2023 and March 2024. Data on demographic characteristics, comorbidities, influenza vaccination status, laboratory-confirmed influenza infection, intensive care unit (ICU) admission, in-hospital mortality, and length of hospital stay were obtained from electronic health records. Logistic regression analyses were performed to evaluate the associations between influenza vaccination and clinical outcomes. RESULTS: Among 485 patients, 114 (23.5%) had received the seasonal influenza vaccine. The prevalence of laboratory-confirmed influenza infection was similar among vaccinated and unvaccinated patients (57.9% vs. 58.5%, p-value = 0.910). Vaccinated patients were less likely to require ICU admission (1.8% vs. 7.5%, p-value = 0.025), while no significant differences were observed in length of hospital stay or in-hospital mortality. After adjustment for age, sex, and comorbidities, influenza vaccination was associated with lower odds of ICU admission (OR = 0.200, 95% CI: 0.045, 0.894). No significant associations were observed between influenza vaccination and laboratory-confirmed influenza infection, length of hospital stay, or in-hospital mortality. CONCLUSIONS: Among adults hospitalized with CAP in Saudi Arabia, influenza vaccination was associated with a lower likelihood of ICU admission, supporting its potential role in reducing disease severity among high-risk populations.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.