Flu (Influenza) Explained | Types, Causes, Symptoms & Effective Treatments

Ever wondered why some colds knock you out harder than others? You might not just be dealing with a regular cold. It could be the flu virus, also known as influenza.

This illness hits harder, spreads faster, and lingers longer than your average sniffles. So, let’s explore everything about flu in a simple and friendly way.

What is Flu (Influenza)?

The flu (influenza) is a respiratory infection that affects your nose, throat, and lungs.

It spreads through tiny droplets when someone coughs, sneezes, or even talks. Every year, especially in the winter months, many people catch the flu at the same time. This leads to what’s called a flu epidemic.

Types of Flu Viruses: Influenza A vs B

There are three main types of flu viruses that affect people: influenza A, B, and C. But when it comes to seasonal flu outbreaks, influenza A and influenza B are the ones to watch out for.

1. Influenza A

This is the most common and the most serious type. It spreads quickly and is responsible for most flu epidemics. Within influenza A, there are various subtypes. Including the well-known H1N1 (swine flu) and bird flu strains.

2. Influenza B

Less severe than A but still packs a punch. It can cause seasonal outbreaks but usually doesn’t lead to pandemics.

3. Influenza C

This one is milder. It’s not seasonal. It typically causes only mild cold-like symptoms, especially in children.

And just to clear up any confusion — the flu is not the same as COVID-19. They’re caused by completely different viruses. Even though some symptoms can be similar.

Flu Causes and Symptoms

What Causes the Flu?

The short answer? The influenza virus.

You can catch the flu by inhaling droplets from a sick person or by touching contaminated surfaces and then touching your face. It’s sneaky and super contagious. Especially in colder months when people spend more time indoors.

Both influenza A and influenza B strike during the flu season, mostly between late autumn and early spring. Influenza C sticks around all year but usually goes unnoticed because it doesn’t cause major symptoms.

With so many symptoms in common, it can be hard to tell the difference between a cold and the flu. Here’s how to tell which is which.

Head Cold Symptoms (usually milder):

• Runny or stuffy nose
• Sneezing
• Sore throat
• Mild fatigue

Flu Symptoms (more intense):

Unlike the common cold, flu symptoms come on quickly and hit hard. You might feel totally fine in the morning and absolutely drained by the evening.

• High fever
• Chills and shivering
• Body aches and muscle pain
• Dry cough
• Headache
• Sore throat
• Runny or stuffy nose (aka congestion)
• Feeling extremely tired or weak
• In some cases, vomiting or diarrhea (especially in children)

Keep in mind: you may not have all these flu symptoms, and that’s totally normal.

Because the flu shares several symptoms with the common cold, it can be tricky to tell them apart. The key difference is flu usually comes on suddenly and feels much more intense.

Is The Flu Contagious?

The short answer is yes — very!

In fact, if you’ve got the flu virus, you can easily pass it on to others without even realizing it. One infected person typically spreads the flu to one or two more people, especially during peak cold and flu season.

So how exactly does the influenza virus travel from one person to another? Let’s break it down.

How Does the Flu Spread?

The flu spreads mainly through tiny droplets in the air or from contaminated surfaces. Here are the most common ways you can catch it:

• Through the Air – If someone nearby coughs, sneezes, or even talks, those invisible droplets can land directly in your nose or mouth — or on your hands, which then touch your face.
• By Touching Contaminated Surfaces – Flu germs can live on things like doorknobs, phones, keyboards, or desks. When you touch those surfaces and then touch your eyes, mouth, or nose, you can unknowingly invite the flu virus in.
• From Direct Contact – Even touching someone’s hand or face when they have the flu can lead to infection. Especially if you touch your own face afterwards.

How Soon Will I Get Sick After Being Exposed?

After being exposed, symptoms of flu usually show up in 1 to 4 days. This is called the incubation period. That means you could be spreading the virus even before you start feeling unwell yourself.

When Should I See a Doctor About the Flu?

If you think you have the flu, it’s a smart idea to get checked early. That way, if needed, your doctor can prescribe antiviral medications like Tamiflu. It works best when taken soon after symptoms begin.

You should see your healthcare provider if:

• You’re not feeling better after 7–10 days.
• You’ve had a fever for more than 3 days.
• You’re pregnant and experiencing flu-like symptoms.
• You have flu symptoms and a chronic health condition (like asthma, diabetes, or heart disease).

When Should I Go to The Emergency Room?

Some flu cases can become serious or even life-threatening. You should head to the ER immediately if you notice any of the following:

• Very high fever (above 103°F or 40°C)
• Flu that gets better, then comes back worse
• Trouble breathing or shortness of breath
• Ongoing chest or abdominal pain
• Seizures
• Confusion or dizziness
• Little or no urination
• Severe muscle pain or weakness
• Bluish lips, skin, or nails (a sign of low oxygen levels)
• Any worsening of existing medical conditions

Flu Diagnosis and Tests

How Is the Flu Diagnosed?

When you visit your doctor, they’ll start by asking about your symptoms. Things like fever, cough, sore throat, and body aches. They’ll also give you a physical check-up. They often listening to your chest with a stethoscope to hear how your lungs are doing.

To confirm whether it’s the flu, your doctor may order a flu test.

This involves taking a quick sample from your nose or throat using a sterile swab. The sample is then sent to a pathology lab, where it’s tested using a PCR (polymerase chain reaction) test. This test looks for the genetic material of the virus that’s making you sick, giving an accurate diagnosis.

In some cases, your doctor might also test you for COVID-19. Especially if your symptoms are similar or if there’s been a recent exposure.

Flu Treatment and Management

Let’s explore your options once you’ve been diagnosed.

How Is the Flu Treated?

In many cases, the flu can be managed at home with rest and self-care. But in some situations, your healthcare provider might prescribe antiviral medications. These don’t cure the flu, but they can:

• Ease your symptoms faster
• Shorten how long you’re sick
• Reduce the risk of serious complications

You’re more likely to be prescribed antivirals if:

• You’ve had flu symptoms for less than 48 hours
• Your symptoms are severe, even if it’s been more than two days
• You live with or care for someone who’s vulnerable to complications from the flu
• You have a chronic health condition or higher risk for severe illness

What Medications Are Used to Treat the Flu?

There are a few FDA-approved antiviral drugs commonly used to treat influenza:

Important: Always tell your provider about any medical conditions before starting treatment.

Are There Any Side Effects from Flu Medications?

Like most medicines, antiviral drugs can cause side effects. The most common ones include:

• Nausea
• Diarrhea
• Bronchospasm (tightening of the airways), especially from inhaled medications

If you feel anything unusual while taking these, speak to your doctor straight away.

How Can I Manage Flu Symptoms at Home?

Even if you don’t need prescription medication, you can still manage your symptoms and speed up recovery with simple home remedies and over-the-counter (OTC) treatments.

Here’s what can help:

• Rest, rest, and more rest. Let your body heal.
• Stay hydrated with water, broths, and warm fluids.
• Cough suppressants (like dextromethorphan) can calm your cough.
• Take pain relievers like acetaminophen (Tylenol®) or NSAIDs (Advil®, Motrin®, Aleve®) to reduce fever and aches.
• Decongestants like pseudoephedrine or phenylephrine can ease stuffy or runny noses.
• Expectorants (like guaifenesin) help loosen mucus and clear your lungs.
• Use a heat pack or hot water bottle to soothe sore muscles.

Quick Tips: Always check with your doctor before combining OTC meds or using them alongside supplements. Avoid giving aspirin to children under 16 unless advised by a healthcare professional.

Influenza Vaccine: Prevention is Better Than Cure

How Can I Prevent the Flu?

Want to lower your chances of catching the flu? The most effective way is by getting your flu shot every year.

The flu vaccine is designed to protect you from the most common strains of influenza A and B that are expected to circulate each season. There are different types of flu vaccines available. So, your doctor can help you choose the one that’s right for you.

When Should I Get the Influenza Vaccine?

You should aim to get a flu shot once a year — one dose is enough for most people.

Ideally, you should get vaccinated from April onwards. This ensures you’re covered for the peak flu season. Your body gets the strongest protection in the first 3 to 4 months after getting the shot. So, the timing really matters.

Moreover, some people need two doses of vaccine, spaced four weeks apart. This applies to:

• Children aged 6 months to 9 years getting their first flu vaccine.
• People getting their first flu shot after a stem cell transplant, organ transplant, or CAR T-cell therapy.

What Else Can I Do to Avoid Catching the Flu?

While the vaccine is your best defense, these everyday habits can also help reduce your risk:

• Wash your hands regularly with soap and water. If you’re on the go, use an alcohol-based hand sanitiser.
• Don’t share food or drinks, or use the same utensils like forks, spoons, or cups.
• Cover your mouth and nose when sneezing or coughing — use a tissue or your elbow, not your hands.
• Consider wearing a mask if you’re unwell and can’t stay home.
• Stay away from sick people, and avoid close contact if you’re not feeling well yourself.
• Avoid touching your face, especially your eyes, nose, and mouth.

Flu Prognosis: What to Expect If You Get Sick

Most people can recover from the flu at home with rest, fluids, and a bit of TLC. Symptoms usually improve within a few days to a week.

But because the flu can lead to serious illness, especially if you have underlying health conditions — it’s smart to keep an eye on your symptoms and see a doctor if things get worse.

While you’re sick, try to limit contact with others, unless you’re heading to a clinic or hospital.

Flu Complications: Who’s at Higher Risk?

Many people recover just fine from the flu. But it’s important to remember that it can lead to serious and sometimes life-threatening complications. Such as:

• Pneumonia
• Breathing difficulties
• Even death in severe cases

People with certain health conditions or other risk factors are more likely to face complications and may need hospital care.

Who Is at Higher Risk for Complications from The Flu?

You may be at greater risk of severe illness from the flu if you:

• Are under 5 or over 65
• Are pregnant
• Are under 19 and take aspirin regularly
• Have asthma, COPD, or other chronic lung conditions
• Have heart disease, stroke history, or issues with your kidneys, liver, or nervous system
• Struggle with muscle function, making it harder to cough or clear airways
• Have diabetes
• Have a weakened immune system (from cancer, HIV/AIDS, or certain medications)
• Live with blood disorders, like sickle cell disease
• Live in long-term care facilities
• Have obesity (BMI over 30)

Are you protected this flu season?

Get Your Flu Shot Today at Iluka Medical Centre

Your health is your greatest asset—so why take chances with the flu?

At Iluka Medical Centre, we make it easy and stress-free to stay protected. We offer annual flu vaccinations to help protect you from the flu virus, especially during peak flu season. If you’re interested, you can contact us to schedule an appointment or get more details about the vaccine.

From expert GP consultations to onsite pathology and personalised care, we’ve got everything you need under one roof.

Stay protected, stay healthy!

Book Your Appointment Today

FAQs About Flu

Q1. When is flu season?

Flu season typically runs from October to May in the Northern Hemisphere, with the peak period between December and February.

Q2. How do I know if I have the flu or COVID-19?

Flu and COVID-19 share similar symptoms. The only way to know for sure is by getting tested, as they require different treatments.

Q3. What is the difference between the flu and the common cold?

Both share symptoms like a runny nose and cough. But the flu is more severe and can lead to serious complications. Whereas, cold symptoms are usually mild.

Q4. Can I diagnose influenza at home?

Yes, you can use an over-the-counter rapid antigen self-test (RAT) to check for flu and other viruses like COVID-19 and RSV.

Q5. How long does the flu last?

Typically, flu symptoms last from a few days to two weeks, with fever and body aches usually clearing up first. Whereas, a cough and congestion may linger longer.

Q6. How long is the flu contagious?

You can spread the flu a day before symptoms appear and up to a week after they begin. You’re most contagious during the first 3 to 4 days.

Q7. Should I stay at home?

Yes, stay home if you’re sick with the flu to avoid spreading it to others. Keep your child at home until they’re symptom-free.