Flu Vaccination May Cut Stroke Risk by Over 70 Percent in Elderly With Chronic Conditions: Study
China: A recent study conducted in Shanghai has found that influenza vaccination may do more than just protect against seasonal flu-it could also significantly lower the risk of stroke in older adults with chronic health conditions. Published in the Journal of Clinical Hypertension, the research was led by Minna Cheng and colleagues from the Shanghai Municipal Center for Disease Control & Prevention.
The team analyzed data from over two years (August 2017 to July 2019), focusing on individuals aged 60 and above who had chronic obstructive pulmonary disease (COPD) along with either hypertension or diabetes mellitus. The researchers compared the one-year incidence of stroke between those who had received the influenza vaccine and those who had not.
The researchers reported the following noteworthy findings:
- Patients who received the influenza vaccine had up to a 73% lower risk of experiencing a stroke compared to those who were not vaccinated.
- During the 2017–2018 flu season, the adjusted hazard ratio (aHR) for stroke was 0.27 among vaccinated individuals.
- In the 2018–2019 flu season, the aHR was 0.46, reaffirming the vaccine’s protective effect across different time periods.
To ensure robustness, the researchers used Cox proportional hazards regression and Poisson regression models, along with propensity score matching to control for potential confounding variables. The results remained consistent, reinforcing the conclusion that flu vaccination may have a stroke-preventive benefit for elderly individuals with chronic comorbidities.
"The reduction in stroke risk ranged between 54% to 73%, depending on the season and statistical method applied," the authors wrote. They suggest that influenza vaccination should be considered a vital component in managing the health of older adults, especially those already managing complex conditions like diabetes and high blood pressure.
However, the researchers acknowledged several limitations. The study did not account for patients' health-seeking behavior—those more likely to get vaccinated might also be more health-conscious in general. Additionally, data on smoking history and concurrent illnesses like pneumonia or influenza were lacking, which could influence stroke outcomes.
Despite these caveats, the study adds to a growing body of evidence supporting broader health benefits of influenza vaccination. While the observational nature of the study does not allow for firm conclusions about causality, the consistency of findings across multiple analyses makes a compelling case.
"Our findings support the inclusion of influenza vaccination in routine chronic disease management for older adults," the study concluded. The results point to a potentially overlooked benefit of flu shots—stroke prevention—particularly in high-risk groups.
With flu season approaching, these insights could influence public health messaging and clinical practices, reinforcing the importance of annual influenza vaccination for vulnerable populations.
Reference:
Wang, Y., Xu, W., Jin, C., Wang, S., Yan, Q., Wu, F., Huang, Z., Yu, K., Cheng, M., & Shi, Y. (2025). Influenza Vaccination and Short-Term Risk of Stroke Among Elderly Patients With Chronic Comorbidities in a Population-Based Cohort Study. The Journal of Clinical Hypertension, 27(8), e70044. https://doi.org/10.1111/jch.70044
