SARS-CoV-2 is transmitted by exposure to infectious respiratory fluids, and the mechanisms by which this occurs are now better understood. Irrespective of improved understanding of transmission, and despite ongoing knowledge gaps, the available evidence continues to demonstrate that existing recommendations to prevent SARS-CoV-2 transmission remain effective. These include physical distancing, community use of well-fitting masks, adequate ventilation, avoidance of crowded indoor spaces, hand hygiene, respiratory etiquette and environmental cleaning.
Exposure to SARS-CoV-2 occurs in three principal ways: (1) inhalation of very fine respiratory droplets and aerosol particles, (2) deposition of respiratory droplets and particles on exposed mucous membranes in the mouth, nose, or eye by direct splashes and sprays, and (3) touching mucous membranes with hands that have been soiled either directly by virus-containing respiratory fluids or indirectly by touching surfaces with virus on them.
People release respiratory fluids during exhalation (e.g., quiet breathing, speaking, shouting, singing, exercise, coughing, sneezing) in the form of droplets across a spectrum of sizes. These droplets carry virus and transmit infection.
- The largest droplets settle out of the air rapidly, within seconds to minutes.
- The smallest very fine droplets, and aerosol particles formed when these fine droplets rapidly dry, are small enough that they can remain suspended in the air for minutes to hours.
Infectious exposures to respiratory fluids carrying SARS-CoV-2 occur in three principal ways (not mutually exclusive):
- Inhalation of air carrying very small fine droplets and aerosol particles that contain infectious virus. Risk of transmission is greatest within three to six feet of an infectious source where the concentration of these very fine droplets and particles is greatest.
- Deposition of virus carried in exhaled droplets and particles onto exposed mucous membranes (i.e., “splashes and sprays”, such as being coughed on). Risk of transmission is likewise greatest close to an infectious source where the concentration of these exhaled droplets and particles is greatest.
- Touching mucous membranes with hands soiled by exhaled respiratory fluids containing virus or from touching inanimate surfaces contaminated with virus.
There are documented occurrences in which SARS-CoV-2 appears to have been transmitted over long distances or times. These transmission events have typically involved the presence of an infectious person producing respiratory droplets in an enclosed space with poor ventilation. Factors that increase the risk of SARS-CoV-2 infection under these circumstances include:
- Enclosed spaces with inadequate ventilation or air handling within which the concentration of exhaled respiratory fluids, especially very fine droplets and aerosol particles, can build-up in the air space.
- Increased exhalation of respiratory fluids if the infectious person is engaged in physical exertion or raises their voice (e.g., exercising, shouting, singing).
- Prolonged exposure to these conditions, typically more than 15 minutes.
The risk of infection is known to be much lower outdoors where ventilation is better.
Multiple SARS-CoV-2 variants are circulating globally. Potential consequences of emerging variants are the following:
- Ability to spread more quickly in people. There is already evidence that one mutation, D614G, confers increased ability to spread more quickly than the wild-type SARS-CoV-2.
- Ability to cause either milder or more severe disease in people.
- Ability to evade natural or vaccine-induced immunity.
Fully vaccinated people have been found to have a lower likelihood of severe illness and death, even if breakthrough infection occurs. They can still spread infection to others, although for a shorter time.
Window for Transmission
Evidence suggests that SARS-CoV-2 RNA can be detected in people some days before symptom onset, with the highest viral loads around the day of symptom onset, followed by a gradual decline over time. Detection of viral RNA does not necessarily mean that a person is infectious to others.
Community prevalence of COVID-19 and its influence on the possibility of health care worker (HCW) infection within EDs is related to a number of factors. These include the rate at which infections actually occur in the community (infectivity), the rate of removal of infection from the population by either recovery or death, and an individual’s susceptibility to the infection. Sociocultural factors are also important.
Where community transmission rates are high, it is more likely that HCW will be at risk of transmission from asymptomatic or minimally symptomatic individuals, both patients and co-workers, or might themselves transmit infections acquired within the community to patients and co-workers. HCW infections have consequences for affected individuals, but also for health workforces, due to roster depletion caused by quarantine and isolation of health-care workers (“furloughing”), and potential spread to patients.
Guidance for PPE use will therefore depend on the local context in terms of community prevalence and transmission, and other measures in place to contain transmission. PPE will continue to be required by fully vaccinated HCW for the foreseeable future. The above factors should be reviewed by EDs, infectious diseases, and infection prevention and control experts, with jurisdictional guidance, to determine precise recommendations for PPE.
The objective of any review of PPE guidance will always be to maintain the safety of HCW within their workplace using the precautionary principle, and then to ensure the rational and effective use of PPE. PPE guidance should be regularly reviewed, with a strategy to implement the most protective regime of PPE for HCW with step down only when there is clear evidence of safety. Extended use strategies should be implemented where PPE supply concerns exist, or where more efficient for clinical workflow, and supply concerns alone must not trigger downgrading of PPE guidance. EDs routinely encounter new and unknown patients where it is not possible to fully ascertain infection risk, therefore decisions to downgrade PPE use should be approached in a cautious manner.
A risk-based approach should be applied in considering the use of masks for the general public, regardless of vaccination or natural immunity status. In areas of known or suspected community or cluster SARS-CoV-2 transmission, WHO advises that the general public should wear a non-medical mask in indoor settings (e.g. shops, shared workplaces, schools) or outdoor settings where physical distancing of at least 1 metre cannot be maintained. If indoors, unless ventilation has been assessed to be adequate, WHO advises that the general public should wear a non-medical mask, regardless of whether physical distancing of at least 1 metre can be maintained.
|From 19 July 2021, there is no longer a legal requirement to wear face coverings in indoor settings or on public transport.
Lifting restrictions does not mean the risks from COVID-19 have disappeared, but at this new phase of the pandemic response we are moving to an approach that enables personal risk-based judgments.
As part of the risk-based approach, local authorities may permit congregation of fully vaccinated or recovered individuals without wearing masks and without applying physical distancing in indoor private settings in regions with low SARS-CoV-2 incidence (<20/100000 population). With reopening after COVID-19, some governments have revoked legal requirements to wear face coverings in indoor settings or on public transport, while maintaining advice that face coverings should be worn within health and residential care settings.
In community or health care settings, where measures such as mask wearing are recommended, they should continue to apply to everyone.
N95 or equivalent respirators will only provide airborne protection if they properly fit to the individual's face preventing unfiltered air to be drawn inside the mask. Fit testing is performed to determine whether a specific type, model and size of respirator is a suitable fit for an individual and that it is worn correctly to achieve a facial seal. Fit-testing is best performed by specifically trained personnel (with credentials in occupational health and safety). HCWs delivering care to suspected or confirmed COVID-19 patients should be identified, fit-tested and supplied with appropriately fitting masks at the point of clinical care.
Fit checking describes the process that HCWs perform each time a respirator is donned to check that a good facial seal is achieved i.e. the respirator is sealed over the bridge of the nose and mouth and that there are no gaps between the respirator and face.
Fit-testing and fit-checking are part of a hospital’s respiratory protection program.
General measures to limit COVID-19 transmission in the workplace
All staff working in health facilities should be vaccinated. This will reduce the likelihood of contracting COVID-19, and should break through infection occur, will reduce both the severity of illness, and duration of infectivity to others.
All staff working in health facilities (including staff with no patient contact) should also adhere to simple measures that will limit COVID-19 transmission. These include avoiding touching their face or shaking hands with others, practicing respiratory hygiene and cough etiquette, meticulous hand hygiene including before and after touching objects or files that may have been in a clinical area, physical distancing > 1.5m where possible, and not coming to work if they have symptoms of an acute respiratory infection.
Recommended precautions also include avoiding indoor crowded gatherings as much as possible, in particular when physical distancing is not feasible, and ensuring good environmental ventilation in any closed setting.
Workforce reconfigurations of split teams, or creating smaller ‘sub teams’ and establishing social distancing protocols within teams, have been described; a strategy with two medical teams working on alternate seven day periods was associated with reduced infection rates among the healthcare workforce.
Strategies for redeploying HCWs identified as higher risk away from frontline roles should be implemented.
Hospitals should have a plan for the very few healthcare workers who do not pass a fit-test. Respirators including PAPR may be an option. If a HCW fails fit-testing for all available respirators, they should be deployed away from areas with COVID-19 patients or where AGPs are performed.
Infection control and prevention
Vaccination of a substantial majority of the population is an important goal to reduce the prevalence of COVID-19 in the community.
Preventing transmission of COVID -19 relies on a “hierarchy of controls”. PPE is the lowest level of control and least effective. Successful control relies on implementation of measures across the hierarchy.
Other controls, the implementation of which will vary according to the level local community transmission, include:
Ventilation requirements for management of COVID-19
- Use of telehealth where appropriate to reduce the need for patients to attend health facilities to receive care.
- Screening at entry to health facilities; limit and monitor points of entry; limit visitor numbers.
- Administrative controls such as policies, appropriate infrastructure, triage and placement of patients, physical distancing guidance, staff to patient ratios and staff training.
- Environmental and engineering controls aimed at reducing the spread of pathogens and the contamination of surfaces and inanimate objects such as adequate spacing between staff and patients, patients and patients; correct cleaning and disinfection procedures; well ventilated isolation rooms.
- Standard precautions, including hand hygiene (5 Moments) for all patients.
- Patients and health workers should observe respiratory hygiene and cough etiquette.
- Universal source control measures including:
- The use of appropriate masks by health facility staff to reduce transmission of infection between staff, as well as from patients or visitors to staff.
- Patients and visitors to wear masks when entering or moving around health facilities.
- In addition to using standard precautions, individuals including family members and visitors (where permitted) should apply contact, droplet and airborne precautions before entering the room of suspected or confirmed COVID-19 patients.
- Equipment should be either single-use and disposable, or dedicated equipment (e.g. stethoscopes, blood pressure cuffs and thermometers). If equipment needs to be shared among patients, each object should be cleaned and disinfected between use for each individual patient.
- Keyboards, phones, pagers and other mobile devices should be protected from contamination and cleaned regularly.
- Avoid transferring patients out of rooms or clinical treatment zones unless medically necessary. Where transfer is required, patients should wear a surgical/procedural mask during transfer, perform hand hygiene and follow respiratory hygiene and cough etiquette
- Limit the number of HCW interactions by bundling patient care activities or cohorting patients and HCWs where possible or practical.
- Treatment space allocation for high-risk patients should ideally be to a negative pressure room with anteroom (Class N).
- Where not available, a standard isolation room or a single room where there is negative airflow is an acceptable alternative.
- Rooms with positive pressure airflow should be avoided.
- Other clincial treatment spaces require additional risk assessment (Australasian Health Facility Guidelines, part D, Infection Prevention and Control.)
- Where single rooms are not available confirmed COVID-19 patients may be cohorted based on additional risk assessment and management using local facility protocols as guidance.
- Ensure ventilation systems operate properly and provide acceptable indoor air quality for the occupancy level for each space.
- A room with ≥12 air exchanges per hour (ACH) [equivalent to ≥80 L/s for a 4×2×3 m3 room] and controlled direction of air flow is recommended for Airborne Precautions
- In addition to the requirement of ≥12 ACH, in a mechanically ventilated airborne precaution room negative pressure (class N) is required to control the direction of air flow.
- And see: https://www.cdc.gov/infectioncontrol/guidelines/environmental/appendix/air.html#tableb2 for details of ventilation requirements and air changes/hour (ACH) and time required for airborne-contaminant removal by efficiency.
PPE recommendations for Emergency Departments
Choosing the right type of respiratory and eye protection depends on the level of risk of SARS-CoV-2 exposure.
For a healthcare worker in a role that directly faces individuals who may be infected with SARS-CoV-2, infection risk varies with:
- epidemiological risk factors: for the individual and in the population
- symptoms consistent with COVID-19 - location where increased generation of airborne particles is likely, in enclosed areas with low levels of ventilation, or where unexpected air movements may facilitate wider distribution of respiratory particles in the air (eg; opening of doors between spaces with different air pressure)
- closeness and duration of contact
- adherence to transmission-based precautions including safe use and removal of personal protective equipment (PPE)
All healthcare workers providing direct patient care or working within the patient/client zone for individuals with suspected or confirmed COVID-19 should have access to P2/N95 respirators
Local public health authorities are the best source of current information about epidemiological risk factors. Reference to jurisdictional guidance is recommended.
Respiratory and eye protection decision aid (NC10CET)
Additional guidance on the use of PPE
- Use gloves.
- Wear a clean, non-sterile, long-sleeved gown.
- The use of boots, coverall* and apron is not required during routine care.
- A waterproof apron is used for procedures expected to create high volumes of fluid.
- Consider use of a hair cover.
- Practice appropriate donning, doffing and disposal of all PPE and hand hygiene. A trained PPE observer should check technique.
- A particulate respirator# such as N95, P2, or equivalent† should be fit tested
- Always perform a seal (‘fit’) check of the respirator.
- Eye protection - (goggles) or facial protection (face shield) - is used to avoid contamination of mucous membranes.
* Note on use of coverall: There is some evidence that doffing and disposal of coveralls between patients increases the risk of contamination. The use of an apron, which can more easily be doffed, over coveralls is recommended. There is low- to very low-certainty evidence that covering more parts of the body leads to better protection; it is also associated with difficult donning or doffing and less user comfort.
# Do not use P2/N95 respirators with a valve. This may expose others to infection.
† Note on powered air purifying respirators (PAPR): PAPR should only be considered where a clinician cannot find an N95 mask that fits adequately; has facial hair that cannot be removed; AND a PAPR is available along with adequate training in its use. The use of a PAPR with coverall may protect against the risk of contamination better than a N95 mask and gown (risk ratio (RR) 0.27, 95% confidence interval (CI) 0.17 to 0.43) but is more difficult to don (non-compliance: RR 7.5, 95% CI 1.81 to 31.1).
Resuscitation procedures remain a high risk source of general contamination by respiratory and other bodily fluids so mask, eye protection and gloves should be used even when risk of COVID infection is low per epidemiological and clinical criteria.
We recommend that all relevant staff are provided:
- Adequate and ongoing training in PPE use, and broader infection prevention and control procedures.
Opportunities to be fit tested for N95 masks.
- Clearly demarcated donning and doffing areas before entering a room, high-risk zone or cohorted area.
- Clear pathways for notification and management of breaches in PPE or concerns about inadequate or inappropriate PPE supply
- A trained PPE observer or buddy to check correct technique
- Adequate mechanisms for safe disposal of used PPE
Rational use of PPE
We recommend that staff working in high-risk zones or with cohorted patients with suspected or confirmed COVID-19 practice robust but rational use of PPE. Although PPE should ideally be exchanged between each patient encounter, this may not be feasible in the context of limited resources and overwhelming demands for care.
After contact with a patient with confirmed COVID-19, or suspected COVID-19 in a region with known community transmission, or otherwise being exposed to body fluids or contamination, all PPE should be doffed and discarded.
“Extended use” is generally accepted as up to 4 hours continuous use.
We recommend that clinicians observe the following principles in relation to the extended use of face masks:
- Practice ‘extended use’ rather than ‘reuse’ of surgical and N95 masks wherever possible. Discard N95 masks following contact with patients with confirmed COVID-19 (see Table 1 in Section 3).
- Discard masks contaminated with blood, respiratory secretions or other bodily fluids.
- Discard masks following close contact with, or exit from, the care area of any patient co-infected with an infectious disease requiring contact precautions.
- Consider use of a cleanable face shield over an N95 mask and/or other steps (e.g. masking patients, use of engineering controls) to reduce surface contamination.
- Perform hand hygiene with soap and water or an alcohol-based hand sanitiser before and after touching or adjusting the mask (if necessary for comfort or to maintain fit).
- Discard any mask that is obviously damaged or damp, or becomes hard to breathe through.
- Observe strict adherence to hand hygiene practices, standard precautions, and proper PPE donning and doffing technique.
We recommend that clinicians observe the following principles in relation to the rational use of gowns:
- Gown use should be prioritised for clinical care of patients with confirmed COVID-19 or patients with suspected COVID-19 in regions with known community transmission, especially for activities that involve holding the patient close (e.g. in paediatric settings), or when other extensive direct patient contact is anticipated.
- Gowns may also be worn during the care of more than one patient in a single cohort area only, provided that the gown does not come into direct contact with any patient. An apron worn over the gown may be changed between patients.
PPE breach risk assessment
Guidance is available for the assessment of risk for HCW exposure to COVID-19 for fully, partially, and unvaccinated personnel.
The principles are outlined in the summary diagram from NSW Health below (available at https://www.health.nsw.gov.au/Infectious/covid-19/Documents/risk-matrix-hcw-vaccinated.pdf
PPE Breach Risk Assessment key principles
Perform a risk assessment to determine the level of exposure asapplied to COVID-19 suspected/confirmed.
(Adapted and modified from work developed by AUSMAT Quarantine management and operations compendium for the Howard Springs Quarantine Facility for the Repatriation of Australians at the Centre for National Resilience. National Critical Care and Trauma Response Centre. Darwin 2021)
Alignment with regional guidance
We recommend that EDs align their internal PPE procedures with guidance from the relevant government authorities for the following:
- Patient PPE.
- Staff clothing and personal items.
- PPE for resuscitation and invasive procedures
- PPE for clinical encounters.
- Cleaning of rooms.
- Cleaning and reuse of disposable equipment.
- PPE following patient death.
- Infection prevention and control (IPC) in non-clinical areas such as lunchrooms.
- PPE breach risk assessment matrices for vaccinated, partially vacccinated or unvaccinated personnel
We align our recommendations with:
- Selection, use and maintenance of respiratory protective equipment standard AS/NZS 1715: 2009.
- The NHMRC Australian Guidelines for the Prevention and Control of Infection in Healthcare, 2019. [Link]
- The World Health Organisation IPC [Link] and PPE [Link] recommendations.
- Respiratory and eye protection for healthcare workers during the COVID-19 Pandemic Version National COVID-19 Clinical Evidence Taskforce Version 1.0 Published 26 August 2021 https://covid19evidence.net.au/wp-content/uploads/NC19CET-Decison-Aid-Respiratory-and-Eye-Protection-v1.0.pdf
The following resources were used in the preparation of this section:
- National COVID-19 Clinical Evidence Taskforce Clinical Flowcharts https://covid19evidence.net.au/#clinical-flowcharts
- Coronavirus Disease 2019 (COVID-19) CDNA National Guidelines for Public Health Units Version 4.7 24 June 2021 Australian Government Department of Health
- Respiratory and eye protection for healthcare workers during the covid-19 pandemic National COVID-19 Clinical Evidence Taskforce https://covid19evidence.net.au/
- Guidance on the use of personal protective equipment (PPE) for health care workers in the context of COVID-19 https://www.health.gov.au/resources/publications/guidance-on-the-use-of-personal-protective-equipment-ppe-for-health-care-workers-in-the-context-of-covid-19
- US Department of Health and Human Services. Centres for Disease Control and Prevention. Delta Variant: What We Know About the Science. Updated Aug. 26, 2021 https://www.cdc.gov/coronavirus/2019-ncov/variants/delta-variant.html
- US Department of Health and Human Services. Centres for Disease Control and Prevention. Science Brief: Emerging SARS-CoV-2 Variants Updated Jan. 28, 2021 https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/scientific-brief-emerging-variants.html
- World Health Organization (WHO). Considerations for implementing and adjusting public health and social measures in the context of COVID-19 Interim guidance 14 June 2021
- World Health Organization (WHO) Guidelines. Infection prevention and control of epidemic and pandemic-prone acute respiratory infections in health care. 2014. [Link]
- World Health Organization (WHO) Advice on the use of masks in the context of COVID-19
- Interim guidance 1 December 2020. [Link]
- Department of Health, Australian Government. Coronavirus (COVID-19) advice for the health and disability sector. [Link]
- NSW Health COVID-19 website: https://www.health.nsw.gov.au/Infectious/covid-19/Pages/default.aspx
- NSW Health Health Care Worker COVID-19 Risk Assessment Matrix https://www.health.nsw.gov.au/Infectious/covid-19/Pages/advice-for-professionals.aspx
- Clinical Excellence Commission COVID-19 Infection Prevention and Control Manual Version 1.5 - 28 July 2021
- Department of Health, Australian Government. Environmental cleaning and disinfecting principles for health and residential care facilities – Version 2 (26 March 2020) Coronavirus disease (COVID-19). [Link]
- New Zealand Ministry of Health. Personal Protective Equipment Use in Healthcare. [Link]
- Verbeek JH, Rajamaki B, Ijaz S, Sauni R, Toomey E, Blackwood B et al. Personal protective equipment for preventing highly infectious diseases due to exposure to contaminated body fluids in healthcare staff. Cochrane Database of Systematic Reviews 2020. [Link]
- International Liaison Committee on Resuscitation (ILCOR). Consensus on Science with Treatment Recommendations (CoSTR): COVID-19 infection risk to rescuers from patients in cardiac arrest [Draft for public comment]. Online resource. [Link]
- Australian Society of Anaesthetists. N95 vs PAPR for AGPs. 27 March 2020. [Link]
- US Department of Health and Human Services. Centres for Disease Control and Prevention. Optimizing Supply of PPE and Other Equipment during Shortages. Updated 16 July 2020. [Link]
- US Department of Health and Human Services. Centres for Disease Control and Prevention. Interim Infection Prevention and Control Recommendations for Healthcare Personnel During the Coronavirus Disease 2019 (COVID-19) Pandemic. Updated 15 July 2020. [Link]
- US Department of Health and Human Services. Centres for Disease Control and Prevention. Scientific Brief: Community Use of Cloth Masks to Control the Spread of SARS-CoV-2. Updated Nov. 20, 2020
- Klompas M, Morris CA, Sinclair J, Pearson M, Shenoy ES. Universal Masking in Hospitals in the Covid-19 Era. NEJM. 2020;382:e63. [Link]
- Greenhalgh T, Schmid MB, Czypionka T, Bassler D, Gruer DB. Face masks for the public during the covid-19 crisis. BMJ. 2020;369:m1435. [Link]
- Regli A, von Ungern-Sternberg. Fit-testing of N95/P2-masks to protect health care workers. Med J Aust 2020; https://www.mja.com.au/journal/2020/fit-testing-n95p2-masks-protect-health-care-workers [Preprint, 12 August 2020].
- Greenhalgh T, Howard J. Masks for all? The science says yes. fast.ai. 13 Apr 2020. [Link]
- MacIntyre CR, Ananda-Rajah M, Nicholls M, Quigley AL. Current guidelines for respiratory protection of Australian health care workers against COVID-19 are not adequate and national reporting of health worker infections is required. Med J Aust. 2020 [Preprint, 14 July]. [Link]
- Greenberg, N. Mental health of health-care workers in the COVID-19 era. Nat Rev Nephrol. 2020. 16:425–26. [Link]
- Bielicki JA, Duval X, Gobat N, Goossens H, Koopmans M, Tacconelli E et al. Monitoring approaches for health-care workers during the COVID-19 pandemic. Lancet Infect Dis. 2020 [Published Online July 23]. [Link]
Resources that are relevant to this section can be accessed through the Clinical Guidelines web-based material [Link]. COVID-19 related ACEM Resources [Link], COVID-19 related external resources [Link], and the latest Government advice on COVID-19 [Link] are also available
This section has been developed to assist clinicians with decisions about appropriate healthcare in Emergency Departments in Australia and Aotearoa New Zealand during the COVID-19 outbreak. It is a framework for planning and responding to this pandemic, including the assessment and management of patients.
This section is targeted at clinicians only. Patients, parents or other community members using it should do so in conjunction with a health professional and should not rely on the information in the guideline as professional medical advice.
The section has been developed by an expert team of practising emergency physicians, by consensus and based on the best evidence available. The recommendations contained do not indicate an exclusive course of action or standard of care. They do not replace the need for application of clinical judgment to each individual presentation, nor variations based on locality and facility type.
The section is a general document, to be considered having regard to the general circumstances to which it applies at the time of its endorsement.
It is the responsibility of the user to have express regard to the particular circumstances of each case, and the application of the section in each case.
The authors have made considerable efforts to ensure the information upon which it is based is accurate and up to date. However, the situation is rapidly evolving, and a certain amount of pragmatism needs to be employed in maintaining such a ‘living document’. Users of this section are strongly recommended where possible to confirm that the information contained within the document is correct by way of independent sources.
The authors accept no responsibility for any inaccuracies, information perceived as misleading, or the success or failure of any treatment regimen detailed. The inclusion of links to external websites does not constitute an endorsement of those websites nor the information or services offered.
The section has been prepared having regard to the information available at the time of preparation and the user should therefore have regard to any information, research or other material which may have been published or become available subsequently.
Whilst we have endeavoured to ensure that professional documents are as current as possible at the time of their creation, we take no responsibility for matters arising from changed circumstances or information or material which may have become available subsequently.