Flu Shots Can Reduce Adverse Cardiovascular Events

Influenza continues posing a substantial threat to population health and those with cardiovascular risks during the ongoing COVID-19 pandemic. To better quantify those health risks, a meta-analysis was recently published by the JAMA Network Open on April 29, 2022.

This study found a positive association between seasonal flu vaccinations and reduced adverse cardiovascular outcomes.

And is evidence that flu vaccines are a vital measure in preventing cardiovascular events, such as heart attacks.

The researchers found that 3.6% of the 4,510 clinical trial participants who received a flu shot or intranasal live attenuated vaccine experienced a major cardiovascular event in the following year.

In comparison, 5.4% of the 4,491 patients who received a placebo or control had an event.

This 1.8% difference translates into a 45% reduced risk following a flu shot for higher-risk patients with a recent acute coronary syndrome.

This analysis stratified patients (mean age, 65.5 years; 42.5% women; 52.3% with a cardiac history) with and without recent acute coronary syndrome (ACS) within 1 year of randomization.

Overall, influenza vaccine was associated with a lower risk of composite cardiovascular events (3.6% vs 5.4%; RR, 0.66; 95% CI, 0.53-0.83; P < .001).

A treatment interaction was detected between patients with recent ACS (RR, 0.55; 95% CI, 0.41-0.75) and without recent ACS (RR, 1.00; 95% CI, 0.68-1.47) (P for interaction = .02).

And for cardiovascular mortality, a treatment interaction was also detected between patients with recent ACS (RR, 0.44; 95% CI, 0.23-0.85) and without recent ACS (RR, 1.45; 95% CI, 0.84-2.50) (P for interaction = .006).

While 1.7% of vaccine recipients died of cardiovascular causes compared with 2.5% of placebo or control recipients (RR, 0.74; 95% CI, 0.42-1.30; P = .29).

“Applying our findings more broadly, our study highlights the additional or secondary benefits often associated with vaccinations,” said Dr. Jay Udell, a cardiologist at Women’s College Hospital and senior author, in a media release.

“In the current context of the COVID-19 pandemic and ongoing vaccine hesitancy, we are hopeful that our results highlight the positive ancillary benefits of vaccinations – providing greater motivation and encouragement for those who remain uncertain.”

These researchers also advise clinicians to encourage patients with elevated cardiovascular risks to get their annual flu shot.... 'an intervention that remains underutilized despite being low cost, well-tolerated, and impactful.'

Additional flu shoot news is posted at PrecisionVaccinations.com/flu.

Note: The study and media release were edited for clarity and manually curated for mobile readership.