Influenza vaccination reduces hospitalizations and mortality for some cardiovascular events, including stroke and heart failure, in patients with type 2 diabetes, according to a study published in the Canadian Medical Association Journal.

Eszter P. Vamos MD, PhD, from the department of primary care and public health at the Imperial College in London, United Kingdom, and colleagues performed a retrospective cohort study to investigate flu vaccine benefits on 124 503 adults with type 2 diabetes for 7 flu seasons, from 2003-2004 and 2009-2010. Researchers reported 623 591 person-years of observation took place during the study, which was conducted using England’s Clinical Practice Research Datalink to obtain primary and secondary care data.

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Dr Vamos and colleagues reviewed data to find seasonal flu vaccine outcomes on acute myocardial infarction (MI), stroke, influenza or pneumonia and heart failure, and death from all causes. Primary care data was used to determine patients’ vaccination status. Researchers first adjusted for covariates and residual confounding.

During the influenza seasons, hospital admission rates were lower with flu vaccination, according to the data, including those for stroke, heart failure and pneumonia or influenza, and all-cause death. Incidence rate ratios (IRRs) were 0.70, 0.78, 0.85, and 0.76, respectively, all of which were significant. A nonsignificant change was also noted for acute MI, with an IRR of 0.81.The risk reduction was observed during all 7 influenza seasons.

Dr Vamos and colleagues emphasized the size of the study as a strength, as well as exact vaccination date information, long follow-up time, and available laboratory and clinical parameters. They also noted some limitations, including the inability to assess misclassified covariates or outcomes due to situations such as “undiagnosed cases of outcomes or comorbidity and unrecorded medical information.”

“This study has shown that people with type 2 diabetes may derive substantial benefits from current vaccines, including protection against hospital admission for some major cardiovascular outcomes. These findings underline the importance of influenza vaccination as part of comprehensive secondary prevention in this high-risk population,” researchers concluded.


Vamos EP, Pape UJ, Curcin V et al. Effectiveness of the influenza vaccine in preventing admission to hospital and death in people with type 2 diabetes. Can Med Assoc J. 2016. doi:10.1503/cmaj.151059.