Coronavirus disease (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus.
Most people infected with the virus will experience mild to moderate respiratory illness and recover without needing any medical assistance. Some people can still get very sick even if they are fit and healthy. , people with pre-existing conditions and people with compromised immunity are at a higher risk of experiencing severe illness.
COVID-19 symptoms vary from mild to severe – speak to your doctor if you have any concerns. Symptoms may appear any time between 2-14 days after being exposed to the virus.
The symptoms to look for are:
- loss or change in sense of smell or taste
- chills or sweats
- sore throat
- shortness of breath
- runny nose.
Some people may also experience headache, muscle soreness, stuffy nose, nausea, vomiting and diarrhoea.
Most people who test positive for COVID-19 recover completely, but some people may develop long COVID. It may take years before we fully understand the long-term effects of COVID-19.
Recent research is still unclear about how many people who have recovered from the virus experience long-term symptoms.
The most common long-term symptoms are:
- shortness of breath
- chest pain or discomfort
- inability to concentrate
- reduced ability to smell or taste.
Natural immunity is the antibody protection your body creates against the virus. It weakens over time depending upon the person and the virus. For example, a case of COVID-19 may not result in strong or long-lasting natural immunity. The best way to protect yourself is to .
This is why it is important to protect yourself and others by wearing a face mask where required, staying in well-ventilated indoor spaces, and maintaining physical distance of at least 1.5 metres.
The World Health Organisation suggests that COVID-19 can be transmitted by contact with tiny droplets or airborne aerosols from an infected person.
A person can be infected with COVID-19 by touching respiratory droplets like saliva or tears from an infected person. These are spread through coughing, sneezing, kissing, talking, or singing.
These droplets can enter your mouth, nose or eyes and cause infection. This can happen by having close face-to-face contact, being within 1.5 metres of someone with COVID-19, or by touching a contaminated surface before touching your face.
Airborne aerosols are tiny particles that float in the air.
An infected person can produce aerosols from coughing, sneezing, talking, singing or even just breathing that can stay in the air for some time. This means that COVID-19 can be spread through these tiny infectious particles suspended in the air.
Sometimes, the virus can remain in the air for some time in settings such as in indoor spaces with poor ventilation.
A person with COVID-19 has infected cells in their body which release the virus into the environment. Viral shedding occurs when someone 'sheds' COVID-19 by breathing, sneezing, or coughing, or through their faeces and urine.
After recovering from COVID-19, some people can have non-infectious fragments of the virus left in their bodies for some time. These fragments may still return a positive result in a test for the virus, although this result may be weak and prompt further testing to confirm they are no longer infectious (not an active or new case).
Most people can recover from COVID-19 at home.
Early treatment medicines are now available for eligible Victorians who have COVID-19 to prevent them from getting so sick that they need hospital care. To see if you may be eligible and for more information, visit .
In some patients who require oxygen therapy, dexamethasone (a corticosteroid) has been used to reduce the severity of illness. This treatment does not work for people who do not need oxygen and should only be used under the direction of a treating doctor.
Early diagnosis, testing and general supportive care are important.
The virus (called SARS-CoV-2) that causes COVID-19 is different from the virus that causes influenza (flu).
COVID-19 spreads more easily and causes severe illness in some people than seasonal influenza.
The respiratory symptoms caused by the two illnesses can be similar and you can avoid catching both by keeping at least 1.5 metres between yourself and others, staying in well-ventilated indoor spaces, washing your hands often and coughing or sneezing into your elbow or a tissue.
Viruses naturally change or mutate. This can lead to what is known as a variant to the main virus strain.
The Omicron variant of COVID-19 was declared a variant of concern by the World Health Organisation on 26 November 2021.
More research and data are required to understand Omicron’s transmissibility, severity, protection by vaccination, and risk of reinfection, but early reports suggest that:
- Omicron spreads faster than the original virus and the Delta variant.
- Omicron can re-infect those who have had previous strains of COVID-19.
- Omicron variant is the dominant strain in Victoria.
- More data is required to understand whether Omicron causes illness as severe as previous variants.
- Research indicates that a booster shot of the Pfizer or Moderna vaccine is expected to protect against severe illness, hospitalisations, and death due to infection with the Omicron variant.
Reviewed 29 June 2022