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How to tell if you have a cold, flu or COVID-19

You wake up feeling under the weather. Could it be the flu, COVID-19, or just a common cold?

A father helping his young son blow his nose
A father helping his young son blow his nose

You've woken up feeling a bit under the weather. You've got sore throat, a runny nose, and a terrible headache. Could it be the flu, COVID-19, or just a common cold?

In this article, we'll explore the symptoms, treatments, and preventive measures for the three of the most common winter illnesses.

What’s the difference between a cold, a flu, influenza and COVID-19 

Great question! Often we either have a sniffle or cold and call it the flu, or we have actually quite severe symptoms and say it’s just a little cold. It’s important to understand that there’s a difference in severity between a cold, influenza (yep, that’s the flu!) and COVID-19. With some needing hospitalisation and resulting in longer-term health problems, let’s get our definitions clear.  

Related: Think you have cold, flu or COVID-19 symptoms? Try our Symptom Checker today. 

2020 flu infographic image

What is influenza?

Influenza, known commonly as the flu, is a respiratory illness caused by a virus. Specifically, influenza is caused by type A, B or rarely type C influenza viruses.

Symptoms of Influenza

Influenza will most often show up with the following symptoms: 

  • Fevers and/or chills 

  • Cough (moderate to severe) 

  • Sore throat 

  • Runny or stuff nose 

  • Muscle or body aches 

  • Headaches 

  • Fatigue.  

Though most instances of influenza will result in significant but not life-threatening symptoms, it can be very severe and even result in hospitalisation or death. Symptoms will usually last around seven days.  

What is the common cold?

Though the common cold is also a respiratory illness caused by viruses, unlike influenza it can be caused by multiple types of viruses that include rhinoviruses, parainfluenza viruses, and seasonal coronaviruses.

Symptoms of the common cold

Symptoms of the cold are often similar to influenza, but typically less severe. You may also experience: 

  • Sneezing 

  • Watery eyes 

  • Tickle in the throat (that may not develop to pain). 

These symptoms will typically not create major or long-term health problems and last around seven days.

What is COVID-19?

COVID-19 is also a respiratory virus caused by the coronavirus (SARS-CoV-2). It is believed to spread more quickly than influenza and lasts longer (anywhere from 2-14 days, and can also result in Long Covid).

What are the symptoms of COVID-19?

COVID-19 symptoms can differ in severity significantly from person to person and can be asymptomatic, however some common symptoms are: 

  • Flu symptoms 

  • Loss of taste and smell 

  • Shortness of breath or difficulty breathing 

  • Nausea 

  • Aversion to drinking fluids

How do I know it’s not hay fever allergies?

Hay fever is an immune system response to environmental allergens like pollen from trees, grass and flora that create a response from your immune system. This is unlike the common cold, flu or COVID-19 which are all virally triggered.  

However, it isn’t uncommon to initially confuse symptoms of runny nose, itchy throat, coughing and sneezing. To differentiate, hay fever allergies shouldn’t cause symptoms like shortness of breath (unless you have a pre-existing respiratory condition like asthma, that can be triggered by pollen), fever, muscle aches, fatigue or nausea.  

Related: Hay fever symptoms and treatment.  

Could my symptoms be due to RSV? How do I tell the difference? 

Respiratory Syncytial Virus (RSV) is a viral infection that can be the cause of the common cold, usually resulting in mild symptoms. However, symptoms can still be severe, particularly to more vulnerable people (particularly very young children), posing a greater risk to health, and even life.  

The symptoms of RSV are much the same as influenza, common cold and COVID-19, but coughing can continue for up to four weeks.  

It is important to get the right diagnosis, so if you or your child are developing any of the above-mentioned symptoms you can use our free symptom checker tool to analyse your symptoms, or see your GP for an in-person or telehealth consultation.

Is there a cure for influenza, common cold and COVID-19? 

Currently there is no cure for any of these viral illnesses, however you can treat symptoms effectively to help dilute the severity. See your GP via telehealth or in person if your symptoms get worse or last longer than seven days.  

Some effective treatments to help with the symptoms are: 

  • Ibuprofen or paracetamol 

  • Decongestants 

  • Getting plenty of rest 

  • Keeping up with your fluids 

  • Inhaling steam from a hot bath or enclosed shower 

If you have a sore throat: 

  • Gargling with warm salty water 

  • Sucking and ice block, ice cube or lozenge 

  • Drinking warm water with honey and a squeeze of fresh lemon juice 

Having common cold, flu or (especially) COVID-19 symptoms means you are very contagious and could spread your illness to others, even just by being in the same room. You are also likely to be feeling quite run down. A convenient and socially responsible way to seek medical attention for mild to moderate symptoms is through telehealth services, such as through our health partnership with 24-7 MedCare, who can diagnose remotely.

You can also have prescriptions delivered to your door through our partnership with so you don’t have to leave the comfort of home. 

Please note: The information throughout this article serves as broad information and should not replace any advice you have been given by your medical practitioner.