Get a Flu Shot and Prevent a CV Event -- It's That Simple

Charles P. Vega, MD


March 24, 2014

In This Article

Universal Flu Vaccination: Are We Paying Attention?

Despite recommendations for universal vaccination of all individuals older than 6 months, influenza vaccine uptake in the United States remains dismal. Although there are clear benefits of large-scale vaccination in terms of both use of healthcare resources and improved work productivity, the issue of whether the influenza vaccine may prevent cardiovascular (CV) events has been controversial.

However, a new meta-analysis finds that the influenza vaccine may reduce the risk for CV events by more than one third among adults, and even more among adults at high risk for CV disease (CVD).[1] These findings could have important implications for public health policy, as well as the way in which physicians counsel individual patients regarding the use of the influenza vaccine.

The Health and Economic Consequences of Flu

This year's flu season (2013-2014) has been particularly challenging, according to the US Centers for Disease Control and Prevention (CDC). The rates of influenza-like illness have been generally elevated above normal, and over 10% of respiratory specimens tested for influenza were positive in late February 2014.[2] Over 40,000 cases of influenza have been diagnosed in total for this flu season in the CDC sentinel database alone.

These cases are associated with substantial risks for morbidity and mortality. An analysis of the impact of influenza in the United States concluded that the virus resulted in a total of over 3 million days of hospitalization and over 31 million outpatient visits.[3] The direct medical costs of influenza exceeded $10 billion, and mortality due to influenza resulted in over 600,000 life-years lost.

The influenza vaccine forestalls these human and economic costs. An analysis of the effect of improving vaccine coverage of high-risk individuals from current levels to 100% across the European Union (resulting in an additional 144 million vaccinations annually) calculated that full coverage would reduce the number of influenza cases by over 7 million annually.[4] This in turn would reduce the number of annual physician visits for influenza by nearly 2 million and the number of hospital admissions by nearly 800,000. The program of complete vaccination for high-risk individuals would save over 68,000 lives lost to influenza-related mortality annually and would save approximately €2 billion per year in direct medical costs alone.

Nonetheless, the influenza vaccine is widely underused. Simplified guidelines from the CDC recommend universal vaccination annually for all individuals 6 months of age or older.[5] However, in the 2011-2012 flu season, only 56.7% of children and adolescents received the flu vaccine.[6] Total coverage among adults was a highly disappointing 38.3%. Even among healthcare workers, many of whom are subject to mandates with either incentives or penalties to encourage influenza vaccination, only two thirds of individuals received the influenza vaccine.

The flu vaccine has been associated with a reduction in CV risk in multiple studies, so it would make sense that patients with elevated cardiovascular risk have higher rates of vaccination. But a study of this issue found that the rate of vaccine coverage among high-risk CV patients was only 57%.[7] Moreover, most high-risk CV patients had unvaccinated contacts at home, and only 65% of patients with CVD considered themselves to be at high risk for complications of influenza.

Patient and physician attitudes toward the influenza vaccine might change if there were solid evidence that it could prevent not only a bothersome flu but also important events, such as myocardial infarction. The current systematic review and meta-analysis addresses this issue.


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