Skip to main content


Page last updated on 30 September 2021

COVID-19 is disease caused by a coronavirus (SARS-CoV2), which until late 2019 had not previously been identified in humans.1 It is a highly contagious respiratory illness which has spread rapidly around the world. On 11 March 2020, the World Health Organisation declared it a pandemic.

The disease can range from mild illness to pneumonia.2  Most people will recover, however, in severe cases pneumonia develops and this can be fatal.  The virus can spread from an infected person's mouth or nose in small liquid particles when they cough, sneeze, speak, sing, or breathe heavily.3

Because COVID-19 is a new disease there is very little existing immunity in our community. This means that COVID-19 can spread widely and quickly. People may be highly infectious before their symptoms show. Even people with mild or no symptoms can spread COVID-19.1 Social distancing, good hygiene, contact tracing, testing and vaccination are preventative measures we currently have to manage the disease. 

As of September 2021, there has been over 232 million confirmed cases globally of COVID-19 and over 4.7 million deaths reported to the World Health Organisation.4  In Australia there has been over 100,000 confirmed cases and over 1,200 deaths.

Key disease information

How did the virus get the name ‘Coronavirus’?

Coronaviruses have crown-like spikes protruding from their surface.  The word ‘corona’ is Latin for crown– hence these viruses are called coronaviruses. The coronavirus responsible for causing COVID-19 is called SARS-CoV2.

Is the COVID-19 virus changing into different variants?

Like all viruses, the SARS-CoV-2 virus that causes COVID-19 is continually changing in its genetic structure (its genome).  When a person is infected with a virus there is an opportunity for the virus to change a little. Mostly, these changes don't make the virus more dangerous, though they can help authorities work out where a particular case of the virus originated. However, sometimes the virus can change in ways that make it easier for the virus to spread, or to make people sicker, or both. When this happens, the term "variants of concern" is used.1

As of July 2021, the World Health Organisation has identified four variants of concern circulating around different parts of the world. These are called, Alpha, Beta, Gamma, Delta.5

How can I help prevent the transmission of COVID-19?

To help protect yourself and others:2

  • Practice good hygiene – wash hands often with soap or use alcohol-based hand sanitiser
  • Avoid touching your eyes, nose & mouth
  • Clean & disinfect surfaces and objects which are touched or handled often, such as benchtops, doorknobs, mobile phones, wallets
  • Maintain physical distancing by staying at least 1.5meters away from other people & avoid crowded places
  • Wear masks when physical distancing not possible or as directed by health authorities
  • Cover your mouth/nose when you sneeze or cough
  • Understand the limits that apply at the time to essential & non-essential gatherings
  • Stay home if you feel unwell
  • If you have cold or flu like symptoms seek medical advice and get tested
Why am I being asked to self-isolate for a 14 day period if I was exposed to a confirmed COVID-19 case?

The maximum incubation period (the time between being exposed to a virus and becoming sick) for COVID-19 infection is typically 14 days.  Most people who develop symptoms do so five or six days after coming into contact with the virus. However, it is possible that symptoms can appear anytime from between 1 and 14 days after being exposed to the virus. You should still be tested if you develop symptoms after a 14 day self-isolation period.1 

How long does the COVID-19 virus last on surfaces?

Early research suggests that the length of time that COVID-19 can survive on surfaces may vary under different conditions (e.g. type of surface, temperature or humidity of the environment). Studies suggest that coronaviruses (including preliminary information on the COVID-19 virus) may persist on surfaces for a few hours or up to several days.1

Who is at risk from COVID-19?

In Australia, those at risk of catching the virus are:2

  • those who have been in close contact with someone who has been diagnosed with COVID-19
  • travellers who have recently returned from overseas
  • people in group residential settings
  • people in correctional and detention facilities

Those at high risk of serious illness from COVID-19 are people:

  • aged 70 years and older
  • with compromised immune systems.

Those at moderate risk of serious illness from COVID-19 are:

People with underlying chronic conditions, including – heart disease, chronic lung disease, diabetes, severe obesity.   

For a full list of those at risk and further advice for at risk groups visit: Advice for people at risk of coronavirus (COVID-19) | Australian Government Department of Health

What are the symptoms of COVID-19? Is it possible to have no symptoms at all?

Symptoms of COVID-19 can range from mild illness to pneumonia. Some people will recover easily, and others may get very sick very quickly. People with COVID-19 may experience symptoms such as:2

  • fever
  • respiratory symptoms
  • coughing
  • sore throat
  • shortness of breath.

Other symptoms can include runny nose, acute blocked nose (congestion), headache, muscle or joint pains, nausea, diarrhoea, vomiting, loss of sense of smell, altered sense of taste, loss of appetite and fatigue.

To stop the spread of COVID-19, people with even mild symptoms of respiratory infection should get tested.

While some people don't develop symptoms at all, for people who do develop symptoms these typically appear five to six days after exposure to the virus. However, it is possible that symptoms can appear anytime from between 1 and 14 days after being exposed to the virus.

What is the difference between COVID-19 & Influenza?

Influenza (flu) and COVID-19 are both contagious respiratory illnesses, but are caused by different viruses.  COVID-19 seems to spread more easily than influenza. However, as more people become fully vaccinated against COVID-19, the spread of the virus that causes COVID-19 should slow down.6

Some of the symptoms of flu, COVID-19, and other respiratory illnesses are similar. The difference between them cannot be made based on symptoms alone. Testing is needed to tell what the illness is and to confirm a diagnosis.6

Both influenza & COVID-19 are vaccine-preventable diseases.  The COVID-19 vaccine does not prevent influenza, and the influenza vaccine does not prevent COVID-19. Both vaccines are important to prevent both influenza and COVID-19, as well as their complications.

How do they test for COVID-19?

In Australia, the most common way to be diagnosed with a COVID-19 infection is to do a polymerase chain reaction test, also called a 'PCR test'. This test collects a respiratory sample (a swab) from the back of the nose and throat.1

Testing is available at a local COVID-19 testing or drive-through clinic, directly by GPs, some private pathology collection centres, or at some hospitals.  Each State around Australia has different processes in place, so if you unsure where to get tested contact your GP or check your local State Government website for details of COVID-19 testing sites in your area.

Are there treatments for COVID-19?

Scientists around the world are working to find and develop treatments for COVID-19.7

Optimal supportive care includes, oxygen for severely ill patients and those who are at risk for severe disease and more advanced respiratory support such as ventilation for patients who are critically ill.  Dexamethasone is a corticosteroid that can help reduce the length of time on a ventilator and save lives of patients with severe and critical illness.7 

The World Health Organisation (WHO) does not recommend self-medication with any medicines, including antibiotics, as a prevention or cure for COVID-19.  The WHO is coordinating efforts to develop treatments for COVID-19 and will continue to provide new information as it becomes available.7

What vaccines are available in Australia for COVID-19?

As of September 2021, there are currently three vaccines available in Australia. These are the AstraZeneca COVID-19 vaccine, Pfizer/BioNTech COVID-19 vaccine and Moderna COVID-19 vaccine.

Due to supply constraints of the vaccines, the vaccination rollout is occurring in stages. Use the Australian Government’s Eligibility Checker to find out if you are eligible yet and for which vaccine and where you can get vaccinated.8COVID-19 Vaccine Eligibility Checker | Australian Government Department of Health

Are there long-term health impacts of COVID-19?

Although most people with COVID-19 get better within weeks of illness, some people experience a wide range of new, returning, or ongoing health problems.  Even people who did not have symptoms when they were infected can have post-COVID conditions.9

Long COVID is a range of symptoms that can last weeks or months after being diagnosed with COVID-19, or can appear weeks after infection. Long COVID can happen to anyone who has had COVID-19, even if the illness was mild, or they had no symptoms. People with Long COVID report experiencing different combinations of the following symptoms:1

  • Tiredness or fatigue
  • Difficulty thinking or concentrating (sometimes referred to as “brain fog”)
  • Headache
  • Loss of smell or taste
  • Dizziness on standing
  • Fast-beating or pounding heart (also known as heart palpitations)
  • Chest pain
  • Difficulty breathing or shortness of breath
  • Cough
  • Joint or muscle pain
  • Depression or anxiety
  • Fever
  • Symptoms that get worse after physical or mental activities

VaccineHub offers general information only. Please see a healthcare professional for medical advice

Find a doctor near you

Sources & Citations

1. NSW Health COVID-19 Frequently Asked Questions.

2. What you need to know about coronavirus (COVID-19).

3. Coronavirus disease (COVID-19): How is it transmitted? 
Coronavirus disease (COVID-19): How is it transmitted? (

4. WHO – COVID-19 Dashboard.

5. NSW Govt. Critical Intelligence Unit.

6. CDC – Similarities & Differences between Flu & COVID-19.

7. WHO. Coronavirus disease (COVID-19).

8. Aust Govt. COVID-19 Vaccine Eligibility Checker. 
COVID-19 Vaccine Eligibility Checker | Australian Government Department of Health

9. CDC – Post-COVID Conditions.

MAT-AU-2102057  Date of preparation September 2021