Winter is coming, and with the cold weather comes respiratory viral infections, including influenza.

So now’s a good time to protect yourself and others with the flu vaccine. It’s effective, free and widely available for many high-risk groups. Even if you don’t qualify for a free vaccine, it’s still recommended for you and your family.

Here are five common questions you might have about the flu and the flu vaccine, and our answers.

1. Is the flu really so bad?

Most flu infections are relatively mild and uncomplicated – but not all. Experimental studies, where volunteers are infected with the flu virus or rhinovirus (a cause of the common cold), show the flu is associated with more intense symptoms that last longer.

The flu weakens the natural defences of the lung. This can allow bacterial or fungal infection to become established, leading to secondary pneumonia.

The flu is also thought to trigger heart attacks, stroke and other cardiovascular disease. In young children, it can trigger febrile seizures (childhood seizures caused by a sudden spike in body temperature).

Uncommonly, the flu virus can directly infect body organs other than the lungs, leading to often severe and devastating diseases. These include infection of the brain (causing encephalitis) or heart (myocarditis).

Frail, older people may have a limited capacity to cope with the stress of infection. So for them, the flu can trigger confusion (delirium), dehydration and cause other body systems to fail.

The groups with the highest risk of flu-related hospitalisation are at each end of the age spectrum – young infants and children, and older people, particularly those with other chronic (long-term) illnesses.

The flu is associated with some of the highest rates of hospitalisation compared with other common respiratory viruses, in children and adults.

In 2025, Australia had an estimated 1,744 deaths involving the flu.

2. Do kids really need a flu vaccine?

Of half a million flu cases diagnosed in Australia in 2025, about two in five were diagnosed in those under 18 years. This results in thousands of children admitted to hospital with the flu each year.

Although children with underlying health conditions are more likely to develop complicated influenza, over half of hospitalised cases occur in healthy children.

According to one study, flu was involved in at least 29 children’s deaths in Australia in 2018–23, mostly as a direct cause. Around half of these children were healthy before they contracted the flu.

Two out of three Australian children will avoid a flu infection or flu-related complications with a flu vaccine. That’s a vaccine effectiveness of about 65%.

So a flu vaccine is recommended, every year for every Australian child from six months of age.

3. Does the flu vaccine give you the flu?

There are two types of flu vaccine.

Injectable flu vaccines

Injectable flu vaccines do not contain the flu virus, so cannot give you the flu. These vaccines contain purified haemagglutinin, a protein present on the surface of the flu virus. When you receive this vaccine, your immune system is “primed” to recognise it in the future, should it encounter the flu virus.

Common symptoms after this type of flu vaccine include pain at the injection site, fatigue, headache, muscle and joint pain. These symptoms can easily be mistaken for the flu, but they’re actually your body’s response to the haemagglutinin.

Nasal spray vaccine

This year, the flu vaccine delivered as a nasal spray (FluMist) became available in Australia. It’s registered for use in children 2–17 years, and is available for free in some jurisdictions for certain age groups.

This is what’s called a live-attenuated vaccine. It contains a weakened “live” form of the flu strain that replicates only in the nose rather than deeper inside the body.

After administration, more than half of children will have a blocked or runny nose, and around one in ten have a fever or headache. This occurs as the immune system responds locally, in the nose, to the weakened “live” flu strain.

FluMist does not lead to infection of the lungs and lower airways. So it cannot cause the serious illness or complications we can see with a normal flu infection.

4. Can the flu vaccine ‘overwhelm’ your immune system?

Flu vaccines work by training the immune system on antigens – small, harmless components of the virus.

We are exposed to hundreds of different antigens every day. For example, one study found healthy humans have demonstrable immune responses to hundreds of antigens in food. We are also constantly exposed to antigens on our skin and in our gut, and through natural infection. So a small dose of a few antigens in a flu vaccine is not able to “overload” or “overwhelm” the immune system.

We routinely combine vaccines and vaccination. Sometimes that’s in a combination vaccine such as the combined diphtheria-tetanus-whooping cough vaccine or by administering more than one vaccine at a time. Our routine national childhood immunisation schedule usually recommends between two and four vaccines at a time. For adults, it’s recommended to have your flu vaccine at the same time as a COVID booster or the new vaccine against RSV (respiratory syncytial virus).

There’s no evidence any of these methods “overload” or “overwhelm” your immune system.

5. Is the flu vaccine safe if I’m pregnant?

Pregnant women, their unborn babies and newborns are at high risk of flu complications. So women are recommended a flu vaccine at any stage of their pregnancy.

Studies have examined the safety of flu vaccines in pregnancy. One systematic review compiled results from 40 studies. It found no evidence the injectable flu vaccine was associated with birth defects or stillbirth. Flu vaccines were however associated with lower rates of preterm birth and low birthweight.

Flu vaccines are not generally effective in infants younger than six months. But antibodies transfer from the mother to the baby via the placenta following immunisation, providing protection against infection.

An injectable flu vaccine in pregnancy provides protection to pregnant women, their unborn infant and their newborn baby.

Christopher Blyth, Paediatrician, Infectious Diseases Physician and Clinical Microbiologist, The Kids Research Institute Australia, The University of Western Australia and Allen Cheng, Professor of Infectious Diseases, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

In recent years, there’s been increasing hype about the potential health risks associated with so-called “ultra-processed” foods.

But new evidence published this week found not all “ultra-processed” foods are linked to poor health. That includes the mass-produced wholegrain bread you buy from the supermarket.

While this newly published research and associated editorial are unlikely to end the wrangling about how best to define unhealthy foods and diets, it’s critical those debates don’t delay the implementation of policies that are likely to actually improve our diets.

What are ultra-processed foods?

Ultra-processed foods are industrially produced using a variety of processing techniques. They typically include ingredients that can’t be found in a home kitchen, such as preservatives, emulsifiers, sweeteners and/or artificial colours.

Common examples of ultra-processed foods include packaged chips, flavoured yoghurts, soft drinks, sausages and mass-produced packaged wholegrain bread.

In many other countries, ultra-processed foods make up a large proportion of what people eat. A recent study estimated they make up an average of 42% of total energy intake in Australia.

How do ultra-processed foods affect our health?

Previous studies have linked increased consumption of ultra-processed food with poorer health. High consumption of ultra-processed food, for example, has been associated with a higher risk of type 2 diabetes, and death from heart disease and stroke.

Ultra-processed foods are typically high in energy, added sugars, salt and/or unhealthy fats. These have long been recognised as risk factors for a range of diseases.

It has also been suggested that structural changes that happen to ultra-processed foods as part of the manufacturing process may lead you to eat more than you should. Potential explanations are that, due to the way they’re made, the foods are quicker to eat and more palatable.

It’s also possible certain food additives may impair normal body functions, such as the way our cells reproduce.

Is it harmful? It depends on the food’s nutrients

The new paper just published used 30 years of data from two large US cohort studies to evaluate the relationship between ultra-processed food consumption and long-term health. The study tried to disentangle the effects of the manufacturing process itself from the nutrient profile of foods.

The study found a small increase in the risk of early death with higher ultra-processed food consumption.

But importantly, the authors also looked at diet quality. They found that for people who had high quality diets (high in fruit, vegetables, wholegrains, as well as healthy fats, and low in sugary drinks, salt, and red and processed meat), there was no clear association between the amount of ultra-processed food they ate and risk of premature death.

This suggests overall diet quality has a stronger influence on long-term health than ultra-processed food consumption.

When the researchers analysed ultra-processed foods by sub-category, mass-produced wholegrain products, such as supermarket wholegrain breads and wholegrain breakfast cereals, were not associated with poorer health.

This finding matches another recent study that suggests ultra-processed wholegrain foods are not a driver of poor health.

The authors concluded, while there was some support for limiting consumption of certain types of ultra-processed food for long-term health, not all ultra-processed food products should be universally restricted.

Should dietary guidelines advise against ultra-processed foods?

Existing national dietary guidelines have been developed and refined based on decades of nutrition evidence.

Much of the recent evidence related to ultra-processed foods tells us what we already knew: that products like soft drinks, alcohol and processed meats are bad for health.

Dietary guidelines generally already advise to eat mostly whole foods and to limit consumption of highly processed foods that are high in refined grains, saturated fat, sugar and salt.

But some nutrition researchers have called for dietary guidelines to be amended to recommend avoiding ultra-processed foods.

Based on the available evidence, it would be difficult to justify adding a sweeping statement about avoiding all ultra-processed foods.

Advice to avoid all ultra-processed foods would likely unfairly impact people on low-incomes, as many ultra-processed foods, such as supermarket breads, are relatively affordable and convenient.

Wholegrain breads also provide important nutrients, such as fibre. In many countries, bread is the biggest contributor to fibre intake. So it would be problematic to recommend avoiding supermarket wholegrain bread just because it’s ultra-processed.

So how can we improve our diets?

There is strong consensus on the need to implement evidence-based policies to improve population diets. This includes legislation to restrict children’s exposure to the marketing of unhealthy foods and brands, mandatory Health Star Rating nutrition labelling and taxes on sugary drinks.

These policies are underpinned by well-established systems for classifying the healthiness of foods. If new evidence unfolds about mechanisms by which ultra-processed foods drive health harms, these classification systems can be updated to reflect such evidence. If specific additives are found to be harmful to health, for example, this evidence can be incorporated into existing nutrient profiling systems, such as the Health Star Rating food labelling scheme.

Accordingly, policymakers can confidently progress food policy implementation using the tools for classifying the healthiness of foods that we already have.

Unhealthy diets and obesity are among the largest contributors to poor health. We can’t let the hype and academic debate around “ultra-processed” foods delay implementation of globally recommended policies for improving population diets.

Gary Sacks, Professor of Public Health Policy, Deakin University; Kathryn Backholer, Co-Director, Global Centre for Preventive Health and Nutrition, Deakin University; Kathryn Bradbury, Senior Research Fellow in the School of Population Health, University of Auckland, Waipapa Taumata Rau, and Sally Mackay, Senior Lecturer Epidemiology and Biostatistics, University of Auckland, Waipapa Taumata Rau

This article is republished from The Conversation under a Creative Commons license. Read the original article.