Department of Health

COVID-19 (Coronavirus disease 2019)

'Blue book' COVID-19 information for the health sector, including disease information and public health management.

Key messages

  • COVID-19 is a leading cause of death in Australia.
  • The ongoing and significant burden of disease is driven by continued viral evolution and waning population immunity.
  • The impacts of COVID-19 can be limited through vaccination, antiviral treatment and non-pharmacological interventions that limit transmission such as testing, case isolation, mask wearing, and ventilation improvements.
  • It is estimated that 5-10% of people with COVID go on to develop post-acute COVID symptoms and conditions.
  • Pathology laboratories must notify COVID-19 results.
  • Residential care facilities, including aged and disability residential care, are at higher risk from COVID-19 outbreaks and should notify outbreaks to enable the provision of support.

This page provides COVID-19 guidance for the Health sector. COVID-19 information for the public is available on Better Health ChannelExternal Link . There you'll find information on preventing COVID-19, what to do if you are unwell or have tested positive for COVID-19, or have come in contact with a case.

Notification requirement for COVID-19

In Victoria, COVID-19 is a routine notifiable condition under the Public Health and Wellbeing Regulations 2019. Pathology services must notify all cases to the Department of Health within 5 days. Notification is also required weekly for all testing for this notifiable condition. Notification from clinicians is not required.

Primary school and children’s services centre exclusion for COVID-19

Children diagnosed with COVID-19 are recommended to isolate. They should not attend school or childcare until 5 days after the date of the positive PCR or rapid antigen test result for COVID-19 and until acute symptoms of COVID-19 have resolved.

Acute symptoms include:

  • runny nose
  • sore throat
  • cough
  • shortness of breath
  • fever, chills and/or sweats.

Infectious agent of COVID-19

SARS-CoV-2 is the infectious agent that causes COVID-19 (coronavirus disease 2019). SARS-CoV-2 is a novel coronavirus that was first identified in humans in Wuhan, China, in December 2019.

Novel variants and sub-variants of SARS-CoV-2 have emerged since 2019, affecting transmissibility, the ability of the virus to cause infection and severe illness despite vaccine and naturally derived immunity (immune escape), clinical presentation and the performance of diagnostic and/or therapeutic interventions.

Identification of COVID-19

Clinical features

COVID-19 usually presents with symptoms similar to other acute respiratory infections (ARI) as defined by recent onset of new or worsening of acute respiratory and other symptoms, such as:

  • cough
  • runny nose
  • breathing difficulty
  • sore throat
  • chills and/or sweats
  • fever (≥37.5°C) can occur but is less common in the elderly.

Other symptoms may include:

  • headache, muscle aches, fatigue, nausea, vomiting, diarrhoea, loss of smell and taste, loss of appetite
  • In the elderly, other symptoms to consider include new onset or increase in confusion, change in baseline behaviour, falling, or exacerbation of underlying illness.

Symptoms can take days to weeks to resolve. Some people may have no symptoms.

Increasing age is the most important risk factor for severe illness, with risk significantly increasing around 60-70 years of age. People who are unvaccinated or who have not been vaccinated recently are at greater risk of severe illness.

Risk of severe illness also increases with the number, severity, and nature of comorbidities such as diabetes, heart diseases and obesity, immunosuppression, disability, and frailty. Pregnancy is a risk factor for severe illness. Males also have a higher risk of severe illness.

SARS-CoV-2 can cause severe complications including pneumonia, acute respiratory distress syndrome (ARDS), complications affecting other organ systems, and long-term health issues.

Long COVID

Long COVIDExternal Link is a multi-organ condition that some people have after having COVID-19. Approximately 5-10% of people infected with SARS-CoV-2 continue to experience symptoms that last beyond 3 months after the initial infection or develop new symptoms weeks to months after their diagnosis. Long COVID is most common among people aged 35 to 70 years old.

There are a wide range of symptoms, such as fatigue, shortness of breath, changes in smell or taste, chest pain, difficulty sleeping, anxiety or depression, headache, and cognitive dysfunction. A significant proportion of people experience symptoms so severe it affects their usual activities.

COVID-19 can increase the risk of serious health problems for at least 12 months after getting sick, including a significantly increased risk of heart attacks, strokes or heart inflammation, blood clots in the lungs or elsewhere, kidney damage and severe mental health issues. COVID-19 can exacerbate pre-existing conditions including diabetes and chronic lung disease.

Diagnosis of COVID-19

A ‘confirmed case’ of COVID-19 is usually diagnosed by a positive nucleic acid amplification test (NAAT) for SARS-CoV-2. A confirmed case may also be diagnosed on isolation of SARS-CoV-2 in cell culture with confirmation using a NAAT, or SARS-CoV-2 IgG seroconversion, or a four-fold or greater increase in SARS-CoV-2 antibodies.

A ‘probable case’ is diagnosed by a positive rapid antigen test to SARS-CoV-2.

In this guideline a ‘case’ refers to both confirmed and probable cases.

Repeated infection with COVID-19 can occur. If a recovered case develops new symptoms of an acute respiratory infection within one month of recovery from COVID-19, they should remain at home until symptoms resolve. Those at higher risk of severe illness should seek advice from their doctor and undertake testing for COVID-19. They should consider testing for other respiratory viruses including influenza, to ensure they are able to access treatment, if eligible.

For surveillance purposes, a positive test notified within 35 days of a previously positive test is not considered a new case.

Incubation period

The median incubation period of ancestral strains of SARS-CoV-2 is 5 to 6 days, with a range of one to 14 days.

Studies have shown shorter median incubation periods for both Delta and Omicron variants of concern than ancestral SARS-CoV-2. The median incubation period for recent Omicron variants is approximately 3 days, with a range of 0-8 days.

Public health significance and occurrence

COVID-19 is a leading cause of death and hospitalisation in Victoria. Despite vaccination and other public health measures and use of antiviral medication in those at high-risk of severe illness, sustained community transmission of COVID-19 has been associated with significant excess mortality in Victoria, particularly since 2022.

Continual viral evolution coupled with waning vaccine and naturally derived immunity have resulted in repeated waves of increased infections, hospitalisations, and deaths every 3 to 6 months.

COVID-19 continues to have broad and significant impacts on health and care service provision and disproportionately impacts communities experiencing greatest socioeconomic disadvantage, First Nations people and culturally and linguistically diverse communities.

In addition to the impacts of acute COVID-19, long term impacts include poor health related to ‘long COVID’ conditions and symptoms.

Reservoir for COVID-19

A preliminary report to the World Health Organization suggests an animal origin of SARS-CoV-2 is likely.

There is currently widespread transmission of SARS-CoV-2 in humans across the globe. Multiple animal species have also been identified as potential reservoirs.

Mode of transmission of COVID-19

SARS-CoV-2 is primarily transmitted by exposure to aerosolised particles and infectious respiratory droplets.

Exposure occurs through:

  • inhalation of aerosolised particles
  • inhalation of respiratory droplets, deposits of respiratory droplets and particles on mucous membranes (mouth, nose, eyes), or touching of mucous membranes with hands directly contaminated with virus-containing respiratory fluids
  • fomite transmission through indirectly by touching surfaces contaminated with virus-containing respiratory fluids.

Period of communicability of COVID-19

In general, a person who tests positive for COVID-19 may be infectious for up to 10 days but are most infectious in the 2 days just before their symptoms start, and while they have acute symptoms (runny nose, sore throat, cough, and fever). Most people infected with COVID-19 are still infectious after 5 days.

Individuals with severe illness or who are significantly immunocompromised may have prolonged infectious periods.

Susceptibility and resistance to COVID-19

Immunity to COVID-19 decreases with increasing time since infection and vaccination. Reinfection with new variants characterised by increasing immune escape may occur soon after recent infection.

There is evidence for increased protection for approximately 6 months against severe illness and hospitalisation in people with a recent history of natural infection or booster doses of vaccine.

A positive COVID-19 test 5 or more weeks after a previous positive test is considered a reinfection.

Control measures for COVID-19

Preventive measures

Important measures to prevent the spread of COVID-19 and reduce risk of severe illness include:

  • Face masksExternal Link and other personal protective equipment:a high-quality and well-fitted mask can protect the wearer and others from the virus. In high risk settings such as healthcare and residential care, additional personal protective equipment may be recommended, based on the situation. A fit tested N95/P2 respirator mask will offer a higher level of protection.
  • Vaccination:External Link COVID-19 vaccines are safe and effective in protecting people against severe illness, hospitalisation, and death. People should remain up-to-date with recommended COVID-19 vaccinations. Some workers may be required to be fully vaccinated – see vaccination for healthcare workers. Workplaces may also continue to implement their own vaccination requirements.
  • Ventilation:External Link increasing fresh air by opening windows and doors, making use of existing heating and cooling systems to bring in fresh air, considering use of portable filtration units, such as HEPA (High Efficiency Particle Air) filters, and using ceiling and pedestal fans in combination with greater airflow such as open windows.
  • TestingExternal Link of symptomatic people and close contacts to enable protective behaviours, such as isolation.
  • IsolationExternal Link of people with symptoms until symptoms resolve. See 'Further information' below for resources which contain advice on isolation of COVID-19 cases.
  • Treatment with antiviral medicationfor those at high risk of developing severe illness – see also consumer antivirals informationExternal Link .

Other measures include:

  • personal hygiene practices to reduce transmission, such as hand and respiratory hygiene and surface cleaning and disinfection
  • physically distancing and gathering outdoors.

For further information see:

Control of case

Individual cases are managed by their doctor or other clinical team if required. Antiviral medication may be used in those at higher risk of developing severe illness.

A person diagnosed with COVID-19 should:

  • isolate until 5 days after the date of the positive test result for COVID-19 and until resolution of acute symptoms of COVID-19. They should not attend a workplace or education facility during this time
  • not leave isolation if experiencing acute symptoms of COVID-19: runny nose, sore throat, cough, shortness of breath, fever, chills and/or sweats
  • not go to a healthcare facility or residential care facility for a period of 7 days and until resolution of acute symptoms of COVID-19
  • not visit people at high-risk of severe illness for a period of 7 days and until resolution of acute symptoms of COVID-19
  • have a negative rapid antigen test before visiting any healthcare facility, residential care facility or person at high risk of illness, taken on the day of attendance
  • wear a face mask for 7 days after a positive test when they need to leave home, and are indoors, or unable to physically distance.

A negative rapid antigen test result is a helpful tool to determine if a case is likely to be no longer infectious but should be interpreted in conjunction with the case’s symptoms and duration of illness.

Cases should notify all close contacts in their household, their workplace and/or education facility, and any social contacts if there was contact during their infectious period.

People at high-risk of developing severe illness should seek medical advice about the use of antiviral medication to reduce the risk of hospitalisation or death. They are strongly recommended to test for COVID-19 as soon as they develop symptoms as antiviral medicines are most effective if taken rapidly after diagnosis.

See further down this page for advice about special settings such as aged and disability residential care facilities.

Control of contacts

Close contacts

Close contacts are at risk of developing COVID-19 in the days that follow their last close contact with a person who was infectious with COVID-19.

Close contacts are the people in the household of a case, or people who have spent more than 4 hours in a residential setting with a case during their infectious period.

From notification of exposure to the case, close contacts should:

  • test regularly – if they develop any symptoms, they should stay home and take a test
  • wear a mask when leaving the house for 7 days
  • not visit healthcare or residential care facilities for 7 days
  • if they are workers and required to work in healthcare or residential care facilities, including providing in home care to people at high risk of COVID-19, they should be asymptomatic and should undertake rapid antigen testing 24 hours apart, for 5 days out of 7 days, after being identified as a close contact
  • if they cannot avoid visiting a sensitive setting, undertake a COVID-19 test before visiting and wear a face mask.

Social contacts

Social contacts are people who are not close contacts but have spent more 2 hours in an indoor space with a case or had 15 minutes of face-to-face contact.

Social contacts are recommended to test for COVID-19 if they develop any symptoms and stay at home until well.

See acute respiratory infection in residential care facility guidelines for further information for management of contacts in residential care settings.

People who have tested positive to COVID-19 in the 5 weeks prior to contact with a case are not considered a contact.

Control of environment

Information for cases and carers on infection prevention and control measures including isolation, hygiene measures and cleaning is available here:

For more detailed information:

Outbreak measures for COVID-19

Public health actions focus on outbreaks in high-risk settings, in particular aged and disability residential care (see Special settings).

Outbreaks of COVID-19 within residential care facilities should be notified to the Department of Health or Local Public Health Units (LPHUs). An outbreak in a residential care facility is defined as 2 or more residents testing positive within a 72-hour period. Notification can be done online through the outbreak notification formExternal Link .

See also Management of Acute Respiratory Infection outbreaks, including COVID 19 and influenza, in residential care facilities (RCFs).

Other settings including health services, workplaces and educational settings are also recommended to report outbreaks if risks related to multiple cases are identified, such as critical service failures, or cases or exposed persons are at high risk of serious disease.

Workplaces should follow advice from Work SafeExternal Link .

See also the COVID-19 infection prevention and control guidelines.

Special settings

Healthcare and residential care settings

Preventive measures such as vaccination, ventilation, isolation of people with symptoms and mask use are particularly important in healthcare and residential care facilities.

Healthcare and residential care settings are strongly recommended to optimise ventilation in indoor settings to protect people at high-risk – see guidance on optimising ventilationExternal Link .

Healthcare and residential care settings are also strongly recommended to manage resident/inpatient cases under appropriate precautions for at least 7 days.

In workplaces such as health services, primary care, community care, residential aged and disability care, and emergency services, if either the staff/visitor/client case or the people who interacted with a case were correctly wearing a P2/N95 mask for the duration of contact, and there are no concerns of PPE (Personal Protective Equipment) breach, they are generally considered neither social nor close contacts.

Further recommendations

There are extra recommendations for people visiting or working in healthcare and residential care settings. These are places where there are many people vulnerable to the severe effects of COVID-19, including:

  • residential care facilities, including aged care, disability, and other services
  • healthcare premises, including when healthcare services are provided in people’s homes
  • other care facilities.

These settings should have policies to help manage the risks associated with COVID-19, including use of masks, testing prior to visiting, and management of cases and contacts.

Everyone should undertake a COVID-19 rapid antigen test before visiting.

Masks should be worn by all staff and visitors.

People with COVID-19 symptoms

People with COVID-19 symptoms or who have tested positive should not visit healthcare and residential care settings or with people at high risk of illness due to COVID-19 for at least 7 days after their positive COVID-19 test and until resolution of acute symptoms of COVID-19.

Close contacts

Close contacts should not visit during their 7-day close contact period.

Workers

Workers should not attend work in a healthcare and residential care setting including providing in home care to people at high risk of illness while unwell, and for at least 7 days after the date of a positive COVID-19 test and until resolution of acute symptoms of COVID-19.

Workers who are close contacts should be asymptomatic and follow testing recommendations if they are required to work in sensitive settings during their 7-day close contact period.

Workers in these settings are particularly recommended to keep up-to-date with vaccination recommendations. Some may have mandatory vaccination requirements.

Use of rapid antigen testing to manage risk

A negative rapid antigen test result is a helpful tool to determine if a case remains infectious:

  • If it is essential that a case or close contact visits a sensitive setting, they should undertake a COVID-19 test prior to their visit.
  • Workers who are cases should have a negative rapid antigen test prior to returning to work in sensitive settings. Return to work is not recommended for at least 7 days. If positive, the case should stay home and seek advice.
  • Additional testing to determine release from isolation may be considered for those severely unwell in hospital or residential care facilities, or those with severe immunocompromise, and may also be considered for other cases in residential care settings with residents at high risk from COVID-19 infection, depending on the risk assessment of the situation.

For residential care facilities, see also Management of Acute Respiratory Infection outbreaks, including COVID 19 and influenza, in residential care facilities (RCFs).

Workplaces

COVID-19 cases should notify their workplace if they are diagnosed with COVID-19 and attended an indoor space at the work premises during their infectious period.

Workplaces should have policies to help manage the risks associated with COVID-19.

Education facilities

Education facilities include childcare or early childhood services, outside school hours care services, schools, and school boarding premises.

COVID-19 cases should notify their education facility if they are diagnosed with COVID-19 and attended an indoor space at the facility during their infectious period.

Education facilities should have policies to help manage the risks associated with COVID-19.

Cruise ships

Specific guidance is available for industry for the prevention and management of COVID-19 outbreaks on cruise vessels.

Reviewed 27 February 2024

Health.vic

Contact details

Do not email patient notifications.

Communicable Disease Section Department of Health GPO Box 4057, Melbourne, VIC 3000

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