Flu jabs cut the risk of cardiovascular disease by more than a third, according to a meta-analysis of six randomised controlled trials involving 9,001 patients.

On average, patients were aged 65.5 years, 42.5 per cent were women and 52.3 per cent had a history of heart disease.

Overall, influenza vaccination was associated with a 34 per cent lower risk of a major adverse cardiovascular event (cardiovascular death, hospitalisation for myocardial infarction, unstable angina, stroke, heart failure or urgent coronary revascularisation) during the year-long follow-up compared with the placebo or control group (3.6 and 5.4 per cent respectively). 

The risk of cardiovascular events was 45 per cent lower (6.5 and 11.0 per cent respectively) in patients who experienced acute coronary syndrome (ACS) during the year before randomisation.

The risk of cardiovascular death was 26 per cent lower in those who received influenza vaccination compared with the placebo or control group (1.7 and 2.5 per cent respectively) – a difference that was not statistically significant. Patients with recent ACS who were vaccinated were, however, 56 per cent (2.6 and 5.4 per cent respectively) less likely to die from cardiovascular causes, which was statistically significant.

The number needed to treat to prevent one cardiovascular event was 56 overall and 23 for people with a recent ACS episode. The number needed to treat to prevent one death was 36 in those with a recent ACS.

“These results suggest that clinicians and policy-makers should continue to counsel high-risk patients on the cardiovascular benefits of seasonal influenza vaccination,” the authors conclude.

(JAMA Network Open 2022; 5:e228873)