A flu shot can offer significant protection to patients at high risk for adverse cardiovascular events, the authors of a new study say.

Investigators conducted a meta-analysis of six clinical trials that included adults who were randomly given a flu shot, a matching placebo or standard care. Patients who received the flu vaccine had a 34% lower risk of major adverse cardiovascular events within 12 months when compared with the other cohorts.  

The benefits were even greater in higher-risk patients with recent, acute coronary syndrome — conditions linked to sudden, reduced blood flow to the heart. These study participants had 45% reduced risk of experiencing cardiovascular events in the same time frame, the researchers reported.

Although patients with cardiovascular disease are known to have a relatively low immune response to flu vaccination (often due to the clinical effects of aging), the results show that the potential cardiovascular risk reduction remains “sizable,” they wrote. The investigators, including physician specialists, expect that the new vaccine technology currently in development, such as mRNA technology, will bump this level of protection up even further.

In the meantime, “we urge clinicians to continue counseling their high-risk patients on the cardiovascular benefits of seasonal influenza vaccination, especially given the historically low uptake of this low-cost and well-tolerated intervention,” they concluded.

The study was published in JAMA Network Open.

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