Everything You Need to Know About the Flu

Influenza, or the flu, is a contagious respiratory illness affecting millions of Australians yearly. It spreads easily and causes symptoms like fever, sore throat, blocked nose, muscle aches, fatigue, and headaches. High-risk groups, including pregnant women, young children, the elderly, and those with underlying conditions, should seek medical help if symptomatic. 

Prevention is key. Annual vaccination is the best protection against the flu. Other measures include:

●      Washing hands regularly

●      Avoiding close contact with sick individuals

●      Staying home when unwell

Stay informed, get vaccinated, and practise good hygiene.

What Is the Flu?

The flu is a contagious virus that spreads through coughs, sneezes, or touching contaminated surfaces. Symptoms include fever, sore throat, cough, body aches, and fatigue. People most at risk include young children, the elderly, pregnant women, and those with underlying health conditions like a weakened immune system or diabetes. In these high-risk groups, the flu has a greater chance of causing complications like pneumonia.

Prevention is key. Take home messages are:

• Get vaccinated annually
• Wash hands regularly with soap and water
• Avoid close contact with sick individuals
• Stay home when unwell

Vaccination is the best protection, as the flu virus mutates frequently.

Seek medical attention for severe symptoms such as difficulty breathing, chest pain, or prolonged fever.

Types of Influenza Viruses

There are three main types of influenza viruses that cause seasonal flu in humans: Influenza A, Influenza B, and Influenza C. Types A and B are responsible for the majority of seasonal flu outbreaks, while type C causes milder symptoms and is less common.

Each year, different strains of these viruses circulate, and some can be more severe or widespread than others. Influenza A tends to cause the most severe illness, while Influenza B can still lead to significant health issues, particularly in vulnerable groups such as children and the elderly.

In Australia, the most common type of influenza virus is the A(H3N2) strain, followed by the A(H1N1) and B viruses. These strains can cause mild to severe illness, with some people experiencing complications such as pneumonia or bronchitis.

Learn more about the types of flu viruses.

Flu vs Cold vs COVID-19

Flu, colds, and COVID-19 can cause similar symptoms like cough, fatigue, and body aches. However, the timing, severity, and type of symptoms can help tell them apart. Understanding these differences is important so you can get the right advice, testing, or treatment.

Read more in our Difference between flu, cold and covid blog.

What Causes the Flu?

The flu is caused by influenza viruses, which spread easily through coughs, sneezes, or touching contaminated surfaces. These viruses constantly change through mutations - a process called antigenic drift. This leads to small changes in the virus each year, which is why the flu vaccine is updated annually to match the expected strains.

Influenza A can also be passed from animals to humans; this is called zoonotic transmission.

For example, bird flu can spread from infected birds to people. These animal-related strains are less common but show how unpredictable flu viruses can be.

Thankfully, most seasonal flu cases are mild and preventable. Getting vaccinated each year, practising good hand hygiene, and staying home if you're sick are effective ways to protect yourself and your community.

Symptoms of the Flu

Flu symptoms usually come on suddenly and can make you feel very unwell. The most common signs include:

• High fever
• Muscle aches and joint pain
• Headache
• Extreme tiredness (fatigue)
• Dry cough
• Sore throat
• Runny or blocked nose
• Chills and sweating

In children, the flu may also cause tummy symptoms like nausea, vomiting, or diarrhoea.

Symptoms generally start 1 to 3 days after infection and last around a week. Some people may feel tired or have a lingering cough for longer, even after other symptoms have eased.

Since colds and COVID-19 can cause similar symptoms, it's not always easy to tell them apart without a test. If you're feeling unwell, especially during flu season, it's a good idea to rest, stay home, and speak with your doctor if needed.

For more details, visit our Flu Symptoms blog.

Flu Complications

Most people recover from the flu without problems, but some may develop complications, especially if they are in high-risk groups. These high-risk groups include young children, older adults, pregnant women, or those with chronic health issues.

Common complications include:

• Ear and sinus infections
• Bronchitis
• Pneumonia, a serious lung infection
• Dehydration
• Worsening of existing conditions such as asthma or heart disease

Complications are more likely if symptoms are severe, last longer than a week, or if the person has a weakened immune system.

It's important to recognise signs early, such as difficulty breathing, chest pain, persistent high fever, or extreme tiredness and seek urgent medical attention.

How Is the Flu Diagnosed?

The flu is usually diagnosed by your doctor or healthcare provider based on your symptoms and recent exposure, especially during flu season. Most people don't need tests if their symptoms are typical and they're otherwise healthy.

Testing may be done if you're at higher risk of complications, or if symptoms are unclear. Common tests include rapid antigen tests that give results quickly, and PCR swabs, which are more accurate but take longer to process.

These tests help confirm if you have the flu and can rule out other infections with similar symptoms, such as COVID-19 or strep throat.

Only a healthcare professional can diagnose the flu and recommend the right care or treatment. If you're feeling unwell, especially with flu-like symptoms, it's best to contact your GP or health clinic for advice.

How Long Is the Flu Contagious?

You can spread the flu virus starting about 1 day before symptoms show and remain contagious for 5 to 7 days after you get sick. Kids and people with weakened immune systems might stay contagious for longer.

It's really important to stay home while you're sick to avoid passing the flu to others. You should also wait at least 24 hours after your fever has gone before going back to work, school, or social activities. This helps protect those around you, especially those who are more vulnerable to serious illness.

How to Treat the Flu

At-Home Remedies and Flu Self-Care

If you have the flu, the best care is plenty of rest and staying well hydrated by drinking water, tea, or soup. Over-the-counter medicines like paracetamol or ibuprofen can help reduce fever, headaches, and muscle aches.

Using a humidifier or sitting in a steamy room may ease cough and congestion. Eating light, nourishing foods and staying comfortable in bed also helps your body fight the virus.

Most people recover from the flu without needing medical treatment. Over-the-counter cold and flu medicines can relieve symptoms but don't cure the flu itself.

Avoid antibiotics unless your doctor prescribes them, as antibiotics don't work against viruses like the flu.

Flu Medicines and Antiviral Treatments

Antiviral medicines help reduce flu symptoms and can shorten the duration of illness if taken early, ideally within 48 hours of when symptoms start. They work by slowing down the flu virus in your body.

Not everyone needs antiviral treatment. These medicines are mainly for people who are at greater risk of serious flu complications, such as older adults, young children, pregnant women, or people with chronic health conditions. Your doctor will assess if antivirals are suitable for you.

In Australia, antivirals are only available with a prescription from a healthcare provider.

If you're feeling very unwell or are in a high-risk group, see your doctor as soon as possible to discuss treatment options.

Along with antivirals, rest, fluids, and symptom relief medicines remain important for recovery.

When to Seek Medical Attention

Most people recover from the flu without needing to see a doctor. However, if you're in a higher-risk group, such as young children, older adults, pregnant people, or those with long-term health conditions it's important to watch for warning signs.

You should seek medical help if you experience:

• Trouble breathing or shortness of breath
• Chest pain or pressure
• High fever that won't go down
• Severe or ongoing vomiting
• Feeling very weak, dizzy, or confused
• Symptoms that worsen or don't improve after several days

If you're unsure, you can book a GP appointment or call health helplines like Healthdirect Australia at 1800 022 222 for advice. In Queensland, 13HEALTH (13 43 25 84) is another health helpline.

How to Prevent the Flu

Annual Vaccination

The annual flu vaccine is the most effective way to prevent the flu each year. Because flu viruses change regularly, the vaccine is updated annually to protect against the strains expected in the upcoming flu season.

Vaccination is recommended for everyone over six months of age, especially those at higher risk, including older adults, pregnant people, young children, and those with ongoing health issues. Getting vaccinated not only lowers your chance of catching the flu but also helps reduce the severity of symptoms if you do get sick.

Vaccination is funded by the Australian Government for Medicare-eligible high risk individuals. High risk individuals include people between 6 months and less than 5 years old, ages 65 or older, Aboriginal and/or Torres Strait Islander people over 6 months of age, pregnant people, and individuals with at-risk health conditions (e.g., asthma, diabetes, heart disease).

The best time to get the flu shot is before winter begins, giving your body time to develop immunity.

Vaccination is a simple, safe step that protects you and those around you. For details on how and where to get your flu shot, visit our Flu Vaccination Services page.

Everyday Flu Prevention Tips

Here are some easy ways to reduce your risk of getting or spreading the flu:

• Cover your mouth and nose with a tissue or your elbow when you cough or sneeze.
• Wash your hands often with soap and water, especially after coughing, sneezing, or touching your face.
• Try not to touch your eyes, nose, or mouth, as this can spread germs.
• Stay home if you feel sick to protect others.
• Support your immune system by eating nutritious food, getting plenty of rest, staying active, and managing stress.

While some people take vitamin C or zinc supplements to help their immunity, these should complement and not replace healthy habits.

Flu in Australia: Seasonality and Risk Factors

Flu season usually starts in late autumn and lasts through early spring, from around May to September. Cooler weather encourages people to spend more time indoors, which makes it easier for the flu virus to spread between people.

Flu commonly spreads in places where people gather closely, such as schools, childcare centres, workplaces, public transport, and crowded events. These environments help the virus move quickly through coughs, sneezes, or by touching shared surfaces.

Certain groups including young children, older adults, pregnant people, and those with chronic illnesses are more vulnerable to catching the flu and developing complications.

To keep track of flu activity, Australian health authorities collect information from doctors, hospitals, and laboratories. This surveillance helps identify which flu strains are circulating and when outbreaks occur, guiding vaccination programs and public health advice.

Staying informed and practising good hygiene are key to reducing your risk during flu season.

Who's Most at Risk from the Flu?

Young children under five have weaker immune systems, making it harder to fight infections.

People aged 65 and over often have less effective immunity and may have other health problems.

Pregnant people face changes in their immune and respiratory systems that increase flu risks.

Aboriginal and Torres Strait Islander peoples experience higher rates of chronic illness and may have less access to healthcare, which increases their risk.

Those with long-term health conditions such as asthma, diabetes, or heart disease may face complications from the flu.

People with weakened immune systems, due to illness or treatments like chemotherapy, are also vulnerable.

Vaccination for the high-risk groups listed above is funded by the Australian Government for patients who hold a valid Medicare card.

For more information on flu vaccines for older adults, visit our Flu Vaccines for the Elderly page.

Key Takeaways

• The flu is most common in cooler months and spreads through coughs, sneezes, and touch.
• Wash hands regularly with soap and water and cover your mouth when coughing to reduce spread.
• The yearly flu vaccine helps prevent illness and lessen symptoms if you get sick.
• Rest, stay hydrated, and use simple pain relief for most flu cases.
• Antiviral prescription medicines may be needed, especially if you're at higher risk.
• See a doctor if symptoms get worse or don't improve after a week.
• Stay home when unwell to protect others.

When to Speak to a Doctor

If your flu symptoms worsen or last more than a week, it's a good idea to see a doctor. Seek medical help if you have trouble breathing, chest pain, a high fever that won't go down, severe tiredness, or confusion.

People at higher risk and those with long-term health issues should contact a healthcare professional sooner, even if symptoms seem mild.

FAQs About the Flu

• How do you get rid of the flu fast?

There's no instant cure for flu, but you can support recovery by resting, drinking plenty of fluids, and using paracetamol or ibuprofen to ease fever and aches. Staying home helps to stop the spread of the virus. Antiviral medications, if started within 48 hours, may shorten illness, though they're not needed for everyone. Practising good hygiene like frequent handwashing and covering coughs protects others.

• Is paracetamol a good treatment for the flu?

Paracetamol effectively relieves flu symptoms such as fever, headaches, and muscle pain. It does not cure the illness but makes you feel more comfortable while your body fights the infection. Always take the recommended dose and avoid other medicines containing paracetamol to prevent accidental overdose. Ibuprofen is an alternative but consult a healthcare provider if you have specific health concerns.

• Does vitamin C help with the flu?

Vitamin C can support immune health but taking extra after flu symptoms begin won't speed up recovery. Some studies show Vitamin C supplementation might slightly reduce the duration of colds but doesn't prevent or cure the flu. Maintaining a balanced diet with plenty of fruits and vegetables is the best way to boost immunity.

• How many days should I take off work for the flu?

Most people require about 5 to 7 days off to recover fully and avoid infecting others. You can spread the virus one day before symptoms start and up to a week after. It's important to stay home while experiencing fever and for at least 24 hours after it ends. If you remain fatigued or have a cough, consider additional rest. Those with more severe symptoms or health vulnerabilities may need longer recovery time.

• What is the typical flu recovery timeline?

Flu symptoms usually begin suddenly and last around 5 to 7 days. Fever, body aches, and tiredness peak in the first few days. Most people start feeling better by day five, though cough and fatigue may linger for one to two weeks. Children and older adults often take longer to recuperate.

• How does the flu spread?

It spreads via droplets when someone coughs, sneezes, or talks. Infection occurs by breathing in these droplets or touching contaminated surfaces and then your face. The virus can survive on surfaces for hours. Regular handwashing and avoiding touching your face reduce infection risk. People can spread the flu from one day before symptoms appear to about seven days after.

• Can you catch the flu more than once a year?

Yes, it is possible because flu viruses frequently change. Immunity from past infection or vaccination might not protect against new strains. Annual vaccination is recommended to guard against the most common strains circulating each season. Practising good hygiene and avoiding contact with sick individuals lowers the chance of reinfection.