To investigate the association between high-dose influenza vaccination and the risk of incident Alzheimer dementia in patients aged 65 and older.
Approach:
Key Findings:
High-dose vaccination associated with lower cumulative risk of Alzheimer dementia from months 1 to 25.
Maximum absolute risk difference was approximately 0.5%, with a number needed to treat of 185 at month 25.
Risk ratios ranged from about 0.78 to 0.89, indicating consistently lower risk with high-dose vaccination.
Stronger association observed among women compared to men.
Sustained seasonal high-dose vaccination also linked to lower Alzheimer dementia risk.
Interpretation:
High-dose influenza vaccination may reduce the risk of incident Alzheimer dementia in older adults, but causality cannot be established.
Limitations:
Follow-up limited to 3 years.
Mortality data not available.
Lack of sociodemographic or lifestyle variables in the database.
Potential misclassification in claims-based data.
Residual confounding, including healthy-vaccinee bias, may have influenced findings.
Conclusion:
High-dose influenza vaccine is associated with a significantly lower risk of incident Alzheimer dementia for the first 25 months post-vaccination, with a minimum number needed to treat of 185.
