Media release: Flu vaccine cuts risk of heart attacks and strokes by around one third

Influenza vaccination is one of the most effective and underused ways to reduce the risk of heart attacks and strokes, reducing major cardiovascular events by around one third according to multidisciplinary clinical researchers. 

In the latest Briefing from the Public Health Communication Centre, authors highlight growing evidence that the seasonal influenza vaccine provides important cardiovascular protection in addition to preventing influenza infection.

“Most people think of the flu vaccine as preventing a week of unpleasant symptoms,” says Dr Philip Shirley from the Immunisation Advisory Centre (IMAC). “But the evidence now shows it also significantly reduces the risk of major cardiovascular events such as heart attacks and strokes, an effect comparable to some commonly prescribed heart medications.”

Research summarised in the Briefing shows influenza infection itself can trigger cardiovascular events. Studies have found that people who test positive for influenza can face up to a sixfold increase in the risk of heart attack or stroke in the following week. Hospital-based studies also show patients admitted with confirmed influenza have more than a one in ten risk of experiencing a cardiovascular event during their hospital stay.

“Influenza infection places considerable stress on the heart and blood vessels,” says Dr Shirley. “Influenza can inflame or injure heart muscle, directly leading to pericarditis and myocarditis. More concerning is that it can also replicate within blood vessel walls. This process can destabilise plaques, triggering rupture and clot formation, leading to a heart attack or stroke.”

Cardiovascular disease remains one of the leading causes of death in Aotearoa New Zealand, accounting for around one third of all deaths. Māori and Pacific peoples experience higher rates of cardiovascular disease and tend to develop these conditions at younger ages than NZ Europeans.

Despite the potential benefits of the influenza vaccination, coverage remains relatively low. Around 60 percent of people aged over 65 receive the vaccine annually, with lower uptake among Māori, Pacific peoples and those living in more socioeconomically deprived communities.

 “Increasing uptake of the influenza vaccination, particularly among groups at higher cardiovascular risk, represents an important opportunity to improve health outcomes in Aotearoa New Zealand,” says Dr Shirley. 

The Aotearoa New Zealand influenza vaccination programme begins next week on 1 April.