But University of Auckland Immunisation Advisory Centre researcher Dr Philip Shirley said there was growing evidence the seasonal influenza vaccine also provided important protection from major cardiovascular events, reducing them by about one third.
"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."
A Public Health Communication Centre briefing showed influenza infection itself could trigger cardiovascular events.
Studies found people who tested positive for influenza, faced up to a six-fold increase in the risk of heart attack or stroke in the following week.
Dr Shirley said hospital-based studies also showed patients admitted with confirmed influenza had more than a one in 10 risk of experiencing a cardiovascular event during their hospital stay.
"Influenza infection places considerable stress on the heart and blood vessels.
"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," he said.
Cardiovascular disease remains one of the leading causes of death in New Zealand, accounting for around one third of all deaths.
Māori and Pacific peoples experienced higher rates of cardiovascular disease and tended to develop these conditions at younger ages than New Zealand Europeans.
Despite the potential benefits of the influenza vaccination, coverage remained relatively low, he said.
Around 60% of people aged over 65 received 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 ..." he said.
New Zealand’s influenza vaccination programme begins next Wednesday.
