COVID-19

What COVID-19 is

COVID-19 is a highly contagious respiratory infection. It is caused by a virus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

There are many subtypes, or variants, of SARS-CoV-2. Some variants can transmit more easily from person to person and spread faster.

COVID-19 can cause mild to severe illness. Some people recover within a few days, while other people are at greater risk of getting severely unwell.

Some people may get longer-term effects following their infection. This is known as long COVID (or post-acute sequelae of COVID-19).

COVID-19 is different from seasonal flu and the common cold.

COVID-19 vaccination is the best protection against severe illness from COVID-19.

Why it matters to public health

COVID-19 affects hundreds of thousands of Australians each year.

Unlike flu infections, which usually peak in winter, COVID-19 infections can peak at any time of year.

A rise in COVID-19 infections is known as a wave. Waves occur due to:

new variants circulating in the community
immunity wearing off over time
increased socialising – for example, during holiday periods.

COVID-19 has a major impact on:

individuals – through illness and complications leading to hospitalisation and death
our health system – through added demand on healthcare professionals, clinics and hospitals
businesses and our economy – through missed school and work and reduced productivity.

Because of these impacts, we:

monitor and report on COVID-19 data
publish guidance and advice on how to protect yourself and others from getting COVID-19
plan for how to manage major outbreaks and pandemics.

Read more about the impacts of COVID-19 in Australia.

Symptoms

Common symptoms include:

Symptoms might range from mild to severe. About 1 in 4 people infected will not have any symptoms at all.

healthdirect’s symptom checker can help you decide whether to see a doctor.

Check your symptoms

Onset of symptoms

Symptoms can start from 1 to 14 days after you are exposed.

How it spreads

COVID-19 mainly spreads through droplets or smaller airborne particles from your respiratory tract which contain the virus. When you do things like talk, cough or sneeze, these droplets and particles travel through the air and land on people and surfaces.

Other people can catch COVID-19 when these droplets or particles:

come into contact with their mouth, nose or eyes
are breathed in
land on surfaces or objects which they touch and then touch their mouth, nose or eyes.

The risk of catching COVID-19 from an infected person is highest when you have close, face-to-face contact. But it can occur over larger distances, especially indoors.

Infectious period

The infectious period for COVID-19 can vary, but you are generally considered infectious:

from up to 48 hours before your symptoms appear
from up to 48 hours before you test positive if you have no symptoms – even if you don’t feel sick, you can still spread the virus
until your symptoms are gone, which can be up to 10 days.

Some people may be infectious for longer, such as those who are severely ill or have a weakened immune system.

Prevention

Get vaccinated

The best way to protect yourself against severe illness from COVID-19 is to get vaccinated – the COVID-19 vaccine reduces your risk of severe illness and death.

You can also help protect yourself and those around you by:

regularly washing your hands
coughing or sneezing into your elbow or a tissue and disposing of used tissues in the bin
avoiding touching your eyes, nose and mouth
staying home if you are sick with cold and flu symptoms
avoiding crowded places
wearing a face mask if around other people, especially when indoors
putting physical distance between yourself and others, especially when indoors
improving ventilation, such as by opening windows.

Read about more ways to prevent COVID-19.

High-risk groups and settings

Some people are at greater risk of getting COVID-19 or of getting very sick from it.

COVID-19 can also spread quickly in some crowded places, such as:

hospitals
residential care facilities
childcare centres
schools.

If you are at greater risk, it is especially important to:

get your COVID-19 vaccination
take steps to protect yourself
avoid crowded places
avoid contact with anybody who has COVID-19 or acute respiratory symptoms
see your healthcare professional as soon as symptoms start – they might prescribe antiviral medicines, if appropriate and you are eligible.

People at greater risk of severe disease

People aged 70 years or older are most at risk of severe illness from COVID-19.

COVID-19 also poses a greater risk of severe illness for people:

with some chronic conditions
who are immunocompromised
with a disability
who are pregnant.

People at greater risk of exposure

COVID-19 is circulating in Australia, so anybody can be exposed.

But people are at greater risk of becoming infected if they have had contact with someone who has COVID-19. This is especially true if they have had close and prolonged contact (such as living in the same house).

People who spend a lot of time around others may be more likely to be exposed to COVID-19. This includes through their jobs, living situation, or recreational activities.

Diagnosis and treatment

Your healthcare professional can diagnose COVID-19 with a polymerase chain reaction (PCR) test. The sample is usually collected from your nose or throat with a cotton swab and sent to a laboratory for testing.

You can also test yourself with a rapid antigen test (RAT) that detects COVID-19 – RATs are widely available from supermarkets and pharmacies.

Surveillance and reporting

COVID-19 is a nationally notifiable disease – these are diseases that present a risk to public health.

Health authorities in each state and territory report new laboratory confirmed cases to us daily through the National Notifiable Diseases Surveillance System.

This helps us to:

monitor case numbers around the country
understand who is at risk of severe disease
know where to target public health actions.

We analyse and report on COVID-19 data through:

our COVID-19 dataset
the Australian respiratory surveillance report
our data visualisation tool, where you can filter and search the latest information.

We also report data on outbreaks of COVID-19 in residential aged care homes. This includes:

case numbers in residents and staff
deaths
vaccination rates
medicines provided to residents through the Pharmaceutical Benefits Scheme.

For more information about our surveillance and reporting activities, see our:

Outbreaks

State and territory health departments might respond to outbreaks of COVID-19 in some situations. This could include outbreaks:

in high-risk settings, such as hospitals and residential aged care homes
that involve a new variant that might be of concern to public health.

Read more about how we define and plan for outbreaks and pandemics.

Support

For information about COVID-19 in your state or territory, see:

If you need mental health support, see a list of organisations, websites and services that offer support, counselling and information.

We regularly add new content to this website. This will include more topics and diseases. In the meantime, information about other diseases in Australia is on the Department of Health and Aged Care’s website.

Last updated:

21 February 2025

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