The Trends and Determinants of Seasonal Influenza Vaccination After Cardiovascular Events in Canada: a Repeated, Pan-Canadian, Cross-sectional Study

Introduction: Annual influenza vaccination is recommended for individuals with a history of cardiovascular disease (CVD) events. We aimed to examine (1) the time trends for influenza vaccination among Canadians with a CVD event history between 2009 and 2018, and (2) the determinants of receiving the vaccination in this population over the same period.

Methods: We used data from the Canadian Community Health Survey (CCHS). The study sample included respondents from 2009 to 2018 who were 30 years of age or more with a CVD event (heart attack or stroke) and who indicated their flu vaccination status. Weighted analysis was used to determine the trend of vaccination rate. We used linear regression analysis to examine the trend and multivariate logistic regression analysis to examine determinants of influenza vaccination, including sociodemographic factors, clinical characteristics, health behaviour and health system variables.

Results: Over the study period, in our sample of 42 400, the influenza vaccination rate was overall stable around 58.9%. Several determinants for vaccination were identified, including older age (adjusted odds ratio [aOR] = 4.28; 95% confidence interval [95% CI]: 4.24-4.32], having a regular health care provider (aOR = 2.39; 95% CI: 2.37-2.41), and being a nonsmoker (aOR = 1.48; 95% CI: 1.47-1.49). Factors associated with decreased likelihood of vaccination included working full time (aOR = 0.72; 95% CI: 0.72-0.72).

Conclusion: Influenza vaccination is still at less than the recommended level in patients with CVD. Future research should consider the impact of interventions to improve vaccination uptake in this population.