Flu Vaccination and Heart Protection, What You Should Know

Flu vaccination helps prevent influenza and reduce severe illness. There is also strong interest in how influenza affects the heart. Cardiovascular events can lead to serious time off work, long recovery times, and hospital admission. For employers who want to make staff healthier, New Zealand workplaces can take practical steps before winter to reduce risk.

Flu infection can trigger heart events

Influenza is not only a respiratory illness. It can place extra strain on the body, especially in people with underlying cardiovascular risk. A 2025 review explains that influenza infection can trigger acute cardiovascular events, including heart attacks. The proposed pathways include systemic inflammation, endothelial dysfunction, and increased clotting, which can destabilise plaques and increase the chance of thrombosis.

This matters because the flu spreads quickly in workplaces and households. An infection can lead to fever, dehydration, reduced oxygenation, and higher heart workload. For some people, that can become the tipping point for a heart event. A strong prevention programme helps protect staff across a wide range of health backgrounds.

What studies suggest about flu vaccination and cardiovascular outcomes

The same review brings together evidence that influenza vaccination may reduce cardiovascular event rates. It discusses findings from observational research and randomised trials. The overall picture suggests that vaccinated people experience fewer cardiovascular events, with notable benefit reported in some studies after myocardial infarction.

This does not mean a flu vaccine replaces cardiovascular care. However, it does mean vaccination can be a useful prevention step, especially for people already at higher risk. From a workplace perspective, this is a key point. Flu vaccination supports more than fewer coughs and flu’s, it may also help reduce the chance of severe complications that lead to hospitalisation and prolonged absence.

New Zealand guidance also supports annual vaccination as a routine health measure. Health New Zealand recommends adults get a flu vaccine each year from 1 April. Immunity takes about two weeks to build, so early timing matters for protection before winter peaks.

Note: On the 29th of March, The New Zealand Herald released an article titled “Epidemiologist says influenza vaccine can reduce risk of heart attacks” which may be of interest to support further reading on the topic.

What this means for workplace risk and absence

Cardiovascular events have a high impact on attendance. A heart event usually means emergency care, recovery time, and follow up appointments. Even when an employee returns to work, they may need reduced hours or lighter duties. That can affect teams, rosters, and delivery timeframes.

Flu vaccination cannot remove all risk, but it can help lower the chance of influenza infection and reduce severity. This can mean fewer severe outcomes, fewer long recoveries, and less disruption. It also adds a layer of protection for staff with known heart risk, even if they do not openly discuss their medical history at work.

There is also a wider benefit. Preventing flu at work reduces the chance of staff taking influenza home to vulnerable whānau, including older family members who face higher risk of complications.

A workplace vaccination programme works best when it is easy and planned early. Our process keeps disruption low and improves uptake. Contact our team and we will confirm a suitable clinic date and expected staff numbers.

Sources

• Fröbert, O., Pedersen, I. B., Hjelholt, A. J., Erikstrup, C., & Cajander, S. (2025). The flu shot and cardiovascular protection, Rethinking inflammation in ischemic heart disease. Atherosclerosis.
• Health New Zealand, Te Whatu Ora. (2026, January 3). Adult immunisations.
• Healthify. (2025, April 10). Influenza vaccine, adults.
• Medsafe. (2025, November 10). Influenza vaccine composition.
• Pharmac. (2024, October 16). Influenza vaccine (flu jab), Pharmac’s role.
• RNZ. (2026, March 29). Epidemiologist says influenza vaccine can reduce risk of heart attacks.