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COVID-19

Clear, up-to-date information on COVID-19 to help protect you and your loved ones.

Learn more about COVID-19

Key Summary

  • What it is: COVID-19 is caused by the SARS-CoV-2 virus and spreads mainly through respiratory droplets and close contact.
  • Variants: Multiple variants have emerged since 2019; the latest in Australia is NB.1.8.
  • Symptoms: Range from mild (fever, cough, sore throat) to severe complications like pneumonia; 5–10% of cases may develop long COVID lasting 3+ months.
  • High-risk groups: Adults aged 65+, people with underlying conditions (diabetes, heart disease, obesity, chronic lung or kidney disease), immunocompromised individuals, and pregnant women.
  • Prevention: Vaccination, practising good hygiene, wearing masks when unwell, and isolating if infected remain key measures.
  • Vaccination:
    • Adults ≥75 years: recommended every 6 months.
    • Adults 65–74 years and 18–64 years with severe immunocompromise: every 12 months (or 6 months if higher risk).
    • Other adults and adolescents: every 12 months based on benefit–risk.
  • Safe during pregnancy; mRNA vaccines (Comirnaty JN.1 and Omicron XBB.1.5) recommended.
  • Effectiveness: Booster doses reduce risk of hospitalisation and death by around 65%, but protection wanes over time.
  • Treatment: Antivirals (Paxlovid, Lagevrio, Veklury) available for eligible high-risk patients if started within 5 days of symptoms; hospital care may include oxygen, corticosteroids, or ventilation.
  • Complications: Severe cases may cause lung damage, blood clots, organ injury, or neurological effects; long COVID affects a smaller proportion but can persist for months.

About COVID-19

COVID-19 is a disease caused by a new form of coronavirus, first reported in December 2019. Coronaviruses are a large family of viruses that cause respiratory infections. These can range from the common cold to more serious diseases.

Variants

Covid-19 viruses can mutate (change) themselves when they replicate (make copies of themselves).  Viruses that have mutated in this way are called variants.

There have been many identified SARS-CoV-2 virus variants as the virus mutates and evolves over time. Omicron, a variant of the SARS-CoV-2 virus, was first identified in November 2021 and was officially designated as a variant of concern by the World Health Organization (WHO) shortly thereafter. 

Each variant and subvariant is associated with varying levels of transmissibility, immune escape, and disease severity. The latest in Australia being the NB.1.8.  variant. 

What’s important is for people to stay vigilant, ensure they are vaccinated against the virus (particularly for at-risk individuals with underlying medical conditions), and continue to apply non-pharmaceutical practices during outbreaks.

COVID-19 Symptoms

Symptoms of COVID-19 can range from mild illness to pneumonia. Some people may get very sick very quickly, and most people will recover easily. People with coronavirus may experience symptoms such as:1

  • Fever
  • 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 lethargy.2

If you are concerned that you, or anyone close to you may have COVID-19 symptoms, you can use the HealthDirect COVID- 19 Symptom and Antiviral Eligibility Checker. 

How COVID-19 Spreads

The virus can spread from person to person through:

  • close contact with an infectious person (including in the 48 hours before they had symptoms)
  • contact with droplets from an infected person’s cough or sneeze
  • touching objects or surfaces (like doorknobs or tables) that have droplets from an infected person, and then touching your mouth or face.

Current evidence suggests that the most likely spread is from respiratory droplets between people from close contact with each other.3, 4

People are believed to be most infectious two days before they start showing symptoms.5 However even if people do not show any symptoms, they can still spread the virus to other people.

COVID-19 Complications

Most people will recover from Covid-19 within a few weeks, however it can cause serious complications. Older people and those with underlying medical conditions e.g. heart disease, diabetes, obesity, chronic liver disease, severe asthma and cystic fibrosis may be more likely to develop a more serious illness.6

What causes Covid-19 complications?

Covid-19 complications may be caused by a cytokine storm. Cytokines are inflammatory proteins that can flood the bloodstream after an infection like COVID-19 triggers the immune system. The large influx of cytokines can cause damage to many organs of the body like the heart, lungs, liver and kidneys.7

The most common complications are of the lungs and respiratory system, they are:

  • Pneumonia: an infection that affects one or both lungs. The air sacs in the lungs become inflamed making it harder to breathe. This type of pneumonia may cause scar tissue and long-term damage to the lungs.7
  • Acute Respiratory Distress Syndrome: the lungs become so severely damaged that fluid flows into them which inhibits the body getting oxygen into the bloodstream.7 

The other complications may be:

  • Acute liver injury: when the liver suddenly stops working8
  • Acute cardiac injury: damage to the heart8
  • Secondary infection: when the body develops another infection unrelated to Covid-19 e.g., a bacterial infection like Strep or Staph9
  • Acute kidney injury: an abrupt decrease in kidney function10
  • Septic shock: a life-threatening condition when the blood pressure drops to a dangerously low level after an infection11
  • Disseminated intravascular coagulation: the body doesn’t clot properly, forming abnormal clots which can lead to internal bleeding and organ failure12
  • Blood clots: clumping of blood cells in the blood vessels13
  • Multisystem inflammatory syndrome in children: some organs in the body become severely inflamed. Symptoms include fever, belly pain, vomiting, diarrhoea, headache, rash and confusion14
  • Chronic fatigue: Symptoms may include brain fog, severe fatigue, pain, trouble thinking or dizziness15
  • Rhabdomyolysis: muscles break down and tissues die. As the cells break, a protein is released into the bloodstream which if the kidneys can’t clear, it could be fatal16
  • Damage to the brain: even in young people, COVID-19 can cause strokes and Guillain Barre Syndrome.17,18

People with severe symptoms may be hospitalised and treated in the Intensive Care Unit with mechanical devices such as ventilators. Surviving these experiences can make them more likely to suffer from post-traumatic stress disorder, depression and anxiety.19,20,21

Long COVID

WHO defines Long COVID as the continuation or development of new symptoms 3 months after the initial SARS-CoV-2 infection with these symptoms lasting for at least 2 months with no other explanation.22

The symptoms may include fatigue, shortness of breath and cognitive dysfunction.

10–20% of people with over 17 million people across the WHO European Region have experienced Long Covid during the first two years of the pandemic (2020/21).22 

In Australia, an AIHW review found that 5–10% of COVID-19 cases reported symptoms persisting for more than 3 months with the vast majority resolving within 12 months.23

The key risk factors include: severe COVID-19 illness, comorbidities, female, mid-adult age groups23

Two COVID-19 vaccination doses are associated with a 13% to 47% lower risk of symptoms persisting beyond 4 weeks.24

The Immunisation Coalition has supported the development of the CoRiCal Long-COVID Calculator which provides a personalised risk assessment of developing long COVID 6 months after infection.

Who is Most at Risk?

You are at a high risk of becoming very sick from COVID-19 and needing hospital treatment, if you25:

  • are aged 65 years or older
  • have certain health conditions, including
    • weakened immune system
    • neurological disease, such as stroke or dementia
    • chronic lung disease, such as severe asthma or chronic obstructive pulmonary disease
    • heart disease
    • obesity
    • diabetes
    • chronic kidney disease
  • are pregnant.

High risk settings include25:

  • residential aged care facilities
  • disability care services
  • in-home aged, health and disability care
  • hospitals and other healthcare settings.

Among patients with vaccine breakthrough COVID-19 hospitalisations, 40-44% had immunosuppression.26,27

COVID-19 Prevention

There are several things you can do to prevent the spread of COVID-19, such as;

  • Practise good hygiene: wash your hands, keep home and workplaces clean and covering your mouth when you cough.
  • Masks: wear a mask when you are sick. Make sure the mask covers your nose and your mouth.
  • Isolate: if you have contracted COVID-19 it is strongly recommended that you stay at home. Although it is no longer a legal requirement to isolate, staying at home protects the people around you and the general community from COVID-19. You should avoid entering high risk settings like aged and disability care facilities and hospitals unless seeking immediate medical care. At home, keep the room well ventilated. Monitor yourself for any symptoms and call your health care provider if you have difficulty breathing, loss of speech or mobility, confusion or chest pain. Stay positive, contact family and friends regularly, maintain regular exercise at home and monitor your mental health. The isolation period is 5-7 days or when symptoms have resolved, whichever is the longer period.

COVID-19 Vaccination

ATAGI recommends a COVID-19 vaccine dose every 6 months for28:

  • Adults aged ≥75 years.

ATAGI recommends a COVID-19 vaccine dose every 12 months for28:

  • Adults aged 65—74 years
  • Adults aged 18—64 years with severe immunocompromise.

These groups are also eligible for a dose every 6 months, based on a benefit-risk assessment. A dose every six months is most likely to benefit people with medical risk conditions and/or those living in residential aged care homes28].

The following groups are eligible to receive a COVID-19 vaccine every 12 months, based on a benefit-risk assessment28:

  • All other adults aged 18—64 years
  • Children and adolescents aged 5—<18 years with severe immunocompromise.

Vaccination during pregnancy/breastfeeding: 

Unvaccinated pregnant women are recommended to receive a primary dose of COVID-19 vaccine, which can be given at any time during pregnancy35.

  • Comirnaty JN.1 and Omicron XBB.1.5-based vaccines can be used in pregnancy. Although the latest mRNA COVID-19 vaccines (Comirnaty JN.1 and Omicron XBB.1.5-based vaccines) have not been formally studied in pregnant women, ATAGI considers them suitable and safe for use35]. 

Pregnant women who have previously been vaccinated are not routinely recommended to have a further dose of COVID-19 vaccine. However, they can consider a further dose of COVID-19 vaccine based on presence of underlying risk conditions and/or personal preference35]. 

COVID-19 Treatment

Doctors will need to review patients’ medications and their current medical conditions to decide if a COVID-19 treatment is suitable for them. The types of COVID-19 treatments that are suitable will also depend on the severity of their COVID-19 illness. 

Basic in hospital treatment options include: oxygen for severely ill patients, ventilation for patients who are critically ill and the use of Dexamethasone or other corticosteroids. Antivirals, immune modulators and monoclonal antibodies have also been used.

COVID-19 Antiviral Medication

Antiviral medications can help prevent severe COVID-19 if taken within five days of symptom onset.29

There are three COVID-19 oral antiviral treatments available for the treatment of COVID-1933:

  • Nirmatrelvir and ritonavir (Paxlovid)
  • Molnupiravir (Lagevrio)
  • Remdesivir (Veklury)

These are available for eligible people who are vulnerable to severe disease such as older people, those with comorbidities, people who are immunosuppressed with a script from a GP.

Paxlovid

Paxlovid has provisional approval for the treatment of coronavirus disease 2019 (COVID-19) in adults 18 years of age and older, who do not require initiation of supplemental oxygen due to COVID-19 and are at increased risk of progression to hospitalisation or death.30

Lagevrio

Lagevrio (molnupiravir) has provisional approval for the treatment of adults with COVID19 who do not require initiation of oxygen due to COVID-19 and who are at increased risk for hospitalisation or death.31

Veklury

Remdesivir (Veklury) has provisional approval for the treatment of COVID-19 in adults and adolescents (aged 12 years and older weighing at least 40 kg) with pneumonia, requiring supplemental oxygen.34

Available on Pharmaceutical Benefits Scheme (PBS):

COVID-19 oral antiviral treatments are available through the PBS for eligible patients.

Severity of COVID-19

Mild Illness: Individuals who have any of the various signs and symptoms of COVID-19 (e.g., fever, cough, sore throat, feeling unwell, headache, muscle pain, nausea, vomiting, diarrhea, loss of taste and smell) but who do not have shortness of breath, difficulty breathing or abnormal chest imaging. These individuals do not require oxygen.32

Moderate Illness: Individuals who show evidence of lower respiratory disease (e.g. pneumonia) during clinical assessment or imaging and who have low oxygen levels. These individuals require oxygen. 32

Severe Illness: Individuals who have lower respiratory disease with severely low levels of oxygen in their blood. These individuals require oxygen. 32

Critical Illness: Individuals who have respiratory failure (where the lungs have trouble loading oxygen or removing carbon dioxide), septic shock (blood pressure drops to a dangerously low level after an infection), and/or multiple organ dysfunction. These individuals require oxygen. 32

Natural Treatments

Natural treatments such as zinc, melatonin, vitamin C, vitamin D, and other supplements are readily available and commonly used to help prevent or treat COVID-19; however, there is insufficient data to recommend the use of such for the prevention or treatment of COVID-19.

The Immunisation Coalition takes an evidence-based approach to COVID-19 treatment.

More COVID-19 Information

Australian Department of Health: Coronavirus (COVID-19) resources for the general public
ACT Government: COVID-19
Department of Health and Human Services Victoria: Coronavirus (COVID-19)
Coronavirus Victoria: Translated information about COVID-19
Coronavirus Victoria: Symptoms and Risks
Coronavirus Victoria: Education – Information for parents, students and educators
NSW Health: COVID-19 Frequently Asked Questions
Northern Territory Department of Health: Coronavirus
Western Australia: COVID-19 (Coronavirus)
Queensland Health: Coronavirus(COVID-19)

References

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  2. About COVID-19 [Internet]. health.gov.au. [cited 2024 Aug 27]. Available from: https://www.health.gov.au/topics/covid-19/about
  3. COVID-19 symptoms [Internet]. healthdirect.gov.au. [cited 2024 Aug 27]. Available from: https://www.healthdirect.gov.au/covid-19/symptoms#:~:text=mild%20upper%20respiratory%20tract%20symptoms,mild%20headache
  4. World Health Organization. Coronavirus disease (COVID-19): How is it transmitted? Accessed 19 October 2022
  5. Brooks JT, Butler JC. Effectiveness of Mask Wearing to Control Community Spread of SARS-CoV-2. JAMA. 2021;325(10):998–999. doi:10.1001/jama.2021.1505
  6. Information for people who test positive for COVID-19 [Internet]. covid19.act.gov.au. [cited 2024 Aug 27]. Available from: https://www.covid19.act.gov.au/stay-safe-and-healthy/information-for-people-who-test-positive-for-covid-19
  7. Table: Conditions for which COVID-19 vaccination can be considered [Internet]. immunisationhandbook.health.gov.au. [cited 2024 Aug 27]. Available from: https://immunisationhandbook.health.gov.au/resources/tables/table-conditions-for-which-covid-19-vaccination-can-be-considered
  8. Tazarghi A, Bazoq S, Taziki Balajelini MH, et al. Liver injury in COVID-19: an insight into pathobiology and roles of risk factors. Virol J. 2024;21:65. https://doi.org/10.1186/s12985-024-02332-y
  9. Qiu H, Li J, Li J, Li H, Xin Y. COVID-19 and Acute Cardiac Injury: Clinical Manifestations, Biomarkers, Mechanisms, Diagnosis, and Treatment. Curr Cardiol Rep. 2023 Aug;25(8):817-829. doi: 10.1007/s11886-023-01902-w. Epub 2023 Jun 14. PMID: 37314650.
  10. Jeong H, Malik A, Boricha A, et al. Assessment of blood markers to predict risk of stroke in middle-aged to elderly population using machine learning. Sci Rep. 2021;11(1):13422. doi:10.1038/s41598-021-92220-0.
  11. Aklilu AM, Kumar S, Nugent J, et al. COVID-19−Associated Acute Kidney Injury and Longitudinal Kidney Outcomes. JAMA Intern Med. 2024;184(4):414–423. doi:10.1001/jamainternmed.2023.8225
  12. Cidade JP, Coelho LM, Costa V, et al. Septic shock 3.0 criteria application in severe COVID-19 patients: An unattended sepsis population with high mortality risk. World J Crit Care Med. 2022 Jul 9;11(4):246-254. doi: 10.5492/wjccm.v11.i4.246. PMID: 36051940; PMCID: PMC9305684
  13. Gando S, Akiyama T. Disseminated intravascular coagulation is associated with poor prognosis in patients with COVID-19. Sci Rep. 2024;14:12443. https://doi.org/10.1038/s41598-024-63078-9.
  14. Martin AI, Rao G. COVID-19: A Potential Risk Factor for Acute Pulmonary Embolism. Methodist Debakey Cardiovasc J. 2020 Apr-Jun;16(2):155-157. doi: 10.14797/mdcj-16-2-155. PMID: 32670476; PMCID: PMC7350811.
  15. Multisystem Inflammatory Syndrome in Children (MIS-C) – Symptoms and Causes [Internet]. mayoclinic.org. [cited 2024 Aug 27]. Available from: https://www.mayoclinic.org/diseases-conditions/mis-c-in-kids-covid-19/symptoms-causes/syc-20502550#:~:text=But%20in%20children%20with%20MIS,have%20had%20a%20known%20infection.
  16. Vu QM, Fitzpatrick AL, Cope JR, Bertolli J, Sotoodehnia N, West T, et al. Estimates of Incidence and Predictors of Fatiguing Illness after SARS-CoV-2 Infection. Emerg Infect Dis. 2024;30(3):539-547. https://doi.org/10.3201/eid3003.231194
  17. Rhabdomyolysis is a life-threatening complication in patients with COVID-19 [Internet]. ijidonline.com. [cited 2024 Aug 27]. Available from: https://www.ijidonline.com/article/S1201-9712(23)00713-0/fulltext#:~:text=Rhabdomyolysis%20is%20a%20life%2Dthreatening,in%20patients%20with%20COVID%2D19
  18. COVID-19 related stroke in young individuals [Internet]. thelancet.com. [cited 2024 Aug 27]. Available from: https://www.thelancet.com/article/S1474-4422(20)30272-6/fulltext
  19. Association Between Guillain-Barré Syndrome and COVID-19 Infection and Vaccination [Internet]. neurology.org. [cited 2024 Aug 27]. Available from: https://www.neurology.org/doi/10.1212/WNL.0000000000207900
  20. Post-COVID conditions: Information for healthcare providers. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-care/post-covid-conditions.html. Accessed 19 October 2022
  21. Post-COVID-19 conditions. Centers for Disease Control and Prevention.
  22. COVID-19 (coronavirus): Long-term effects, Mayo Clinic, https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-long-term-effects/art-20490351. Accessed 19 October 2022
  23. WHO Post COVID 19 condition (Long Covid) Fact sheet Accessed 26 April 2023
  24. Australian Government Australian Institute of Health and Welfare Long COVID in Australia- a review of the literature Last updated 16 December 2022
  25. Brosh-Nissimov T et al. Clin Microbiol Infect. 2021;27:1652–1657
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  27. Tenforde MW et al. Clin Infect Dis. 2021;ciab687
  28. Australian Government Department of Health Protect yourself and others from COVID 19 Last updated 14 October 2022
  29. 32. ATAGI statement on the administration of COVID-19 vaccines in 2025 [Internet]. health.gov.au. [cited 2025 July 17]. Available from https://www.health.gov.au/resources/publications/atagi-statement-on-the-administration-of-covid-19-vaccines-in-2025?language=en
  30. Oral treatments for COVID-19 [Internet]. health.gov.au. [cited 2024 Aug 27]. Available from: https://www.health.gov.au/topics/covid-19/oral-treatments
  31. Paxlovid® (nirmatrelvir and ritonavir) Product Information [Internet]. tga.gov.au. [cited 2024 Aug 27]. Available from: https://www.tga.gov.au/sites/default/files/paxlovid-pi.pdf
  32. Lagevrio® (molnupiravir) Product Information [Internet]. tga.gov.au. [cited 2024 Aug 27]. Available from: https://www.tga.gov.au/sites/default/files/lagevrio-pi.pdf
  33. BMJ Best Practice. COVID-19: assessment of severity [Internet]. London (GB): BMJ Publishing Group; 2024 [cited 2024 Nov 22]. Available from: https://bestpractice.bmj.com/topics/en-gb/3000201/criteria?
  34. Victorian Department of Health. Vaccines and medications in patients with COVID-19 [Internet]. Melbourne: State Government of Victoria; [cited 2025 Jul 17]. Available from: https://www.health.vic.gov.au/covid-19/vaccines-and-medications-in-patients-with-covid-19
  35. Therapeutic Goods Administration (TGA). Veklury (remdesivir) – Australian Product Information [Internet]. Canberra: Australian Government Department of Health and Aged Care; [cited 2025 Jul 17]. Available from: https://www.tga.gov.au/resources/auspmd/veklury