Dementia and influenza vaccination ‐ Time trends and predictors of vaccine uptake among older adults

Abstract Background Older adults with dementia are at an increased risk of hospitalizations with respiratory infections and death. This emphasizes the need for increased focus on preventive measures, such as influenza vaccination, in this vulnerable group. The aim of our study was to investigate whether dementia, along with other factors, is associated with likelihood of influenza vaccination among older adults as well as to estimate time trends of vaccine uptake for older adults with dementia. Method We conducted a nationwide cross‐sectional study with data from national registries on the entire Danish population aged ≥65 years. We mapped the time trends of vaccination for each vaccination season (September to August) from 2002/2003 to 2018/2019. Using multivariable logistic regression, we estimated the likelihood of vaccination in 2018/2019 for a combined measure of dementia status and living situation (home living vs. nursing home). In the same model, we estimated the effect of other potential predictors of influenza vaccination. Result The study population was 801,710 individuals in 2002/2003, and 1,122,489 in 2018/2019. In the entire elderly population vaccine uptake increased steadily from 6% in 2002/2003 to 51% in 2009/2010 and then plateaued but was 10% higher among people with dementia. Compared to home living without dementia, the likelihood of vaccination in 2018/2019 was lower for home living with dementia (OR: 0·80; 95% CI: 0·78‐0·82), while it was higher for nursing home residents both with (1·36; 95% CI:1·31‐1·41) and without dementia (1·21; 95% CI: 1·17‐1·25). Higher age, more GP contacts, higher number of drugs and CCI score were associated with higher vaccination likelihood, while lower educational level, lower residential urbanization and being unmarried were associated with lower vaccination likelihood. Conclusion Influenza vaccination coverage has remained below 60% among older adults regardless of dementia status, not reaching the WHO target of 75% immunization in this group. Home‐living older adults with dementia were 20% less likely to receive an influenza vaccination, representing an important target group for future vaccination campaigns