Does a face shield protect against COVID-19? We’re not sure — so a mask is probably a safer bet for now

Philip Russo, Monash University and Brett Mitchell, University of Newcastle

For several weeks, Victorians have been required to wear a face covering when they leave home. And while we now have a clearer path out of lockdown, it’s likely masks will be around for a while.

Meanwhile, people in other states with outbreaks have been encouraged to wear masks, and some people are simply choosing to wear one as a precaution.

But some people in the community, instead of opting for a traditional mask, are instead wearing a face shield.

This might offer some degree of protection — but it’s probably not as good as a mask in preventing the spread of COVID-19.

What is a face shield?

A face shield is a film made from plastic or other transparent material designed to be worn like a visor. It’s attached using a band that goes around the top of your head.

Think of a visor a welder wears to protect themselves from sparks and injury. Health-care workers use face shields to block bodily fluids from coming into contact with their face, and potentially causing infection.

It’s likely many people are choosing face shields during COVID-19 because they’re experiencing discomfort wearing a mask — whether glasses fogging up, irritation around the ears, or just that extra layer.

The term “face covering”, as per the Victorian government’s guidelines, is notably vague. It can include a face mask, a face shield, or a scarf or bandana.

The department of health does however recommend a mask over a face shield.

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How effective are face shields?

A letter, published recently in the journal Physics of Fluids, reported on a laboratory experiment where scientists put face shields to the test.

They simulated coughing by connecting the head of a mannequin to a fog machine, and then using a pump to expel the vapour through the mannequin’s mouth.

They found that while face shields stopped the droplets being propelled forwards, aerosolised droplets — those much smaller in size — lingered at the bottom of the shield and floated around at the sides. They eventually spread approximately 90 centimetres from the mannequins.

A health-care worker looking out the window. She wears full PPE, including a face shield.
Health-care workers may wear face shields to prevent splashes of bodily fluids.

This is an interesting laboratory experiment, but not conclusive evidence face shields offer less protection than masks in the community.

A lack of research on the effectiveness of face shields means it’s not possible to make any strong recommendations for or against their use.

Where does this leave us?

There’s a lot we still don’t know about this virus and how it spreads.

At present, we believe the virus is spread generally through close contact with an infectious person, contact with the droplets emitted when they sneeze or cough, or contact with surfaces these droplets have contaminated.

To establish an infection the virus enters your body through portals of entry: the mouth, nose and eyes.

Wearing a mask is intended to protect others if you have the infection, by blocking the droplets coming out of your mouth and nose. We call this source control. To a degree — though we have less evidence on this front — it’s also likely to protect you, the wearer, by providing a physical barrier to your portals of entry.

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A face shield may offer an advantage in that it provides a physical barrier over all your portals of entry — your eyes as well as your mouth and nose. Shields may also reduce the frequency of the wearer touching their face, and have the added benefit of allowing the person’s face to be seen (if they’re not wearing a mask as well).

However, as they’re not tight fitting, aerosols may still enter and exit around the outside of a face shield, where it’s not fitted in the same way a mask is. And we’re continuing to accumulate evidence about the possible role of aerosolised transmission in the spread of COVID-19, which the World Health Organisation is closely monitoring.

Correct use is important too

Whatever face covering you choose, you must use it properly, and it must fit correctly.

Having masks slung under the chin, hanging off one ear, or your nose poking out over the top of the mask will make them markedly less effective. And of course frequently touching and re-adjusting the mask means we’re possibly contaminating our hands too.

If you don’t intend to wear a mask properly or you’re unable to, then a face shield is a better option. You can also wear mask and a face shield together, should you wish to.

Like masks, there are a variety of face shields available, varying in quality and size. The department of health advise if you wear a face shield it should cover “the wearer’s forehead to below the chin area and wrapping around the sides of the wearer’s face”.

You should not share a face shield. If they’re labelled disposable, don’t reuse them. And if they are reusable you need to clean them regularly following the manufacturer’s instructions.

The upshot

Masks worn correctly are the best option. When wearing a mask is not possible, then a face shield is better than nothing. Neither will work well if not used properly, and importantly, they don’t replace physical distancing and hand hygiene.

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The Conversation

Philip Russo, Associate Professor, Director Cabrini Monash University Department of Nursing Research, Monash University and Brett Mitchell, Professor of Nursing, University of Newcastle

This article is republished from The Conversation under a Creative Commons license. Read the original article.

PPE unmasked: why health-care workers in Australia are inadequately protected against coronavirus


Alicia Dennis, University of Melbourne and Jane L Whitelaw, University of Wollongong

In Victoria, more than 1,100 health-care workers have now been infected with SARS-CoV-2, the coronavirus that causes COVID-19. Some 11% of active cases are workers in the health-care sector.

Health-care workers are reported to be among those fighting for life in Victorian intensive care units.

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While we don’t know what proportion of the Victorian health-care workers currently infected with COVID-19 acquired it at work rather than in the community, it’s almost certain a portion of these infections were contracted in the workplace.

Early experience from China found the proportion of health-care workers who contract COVID-19 can be up to 29% in settings with inadequate personal protective equipment, or PPE.

Lessons from China also show workplace transmission of SARS-CoV-2 can be reduced to negligible numbers with sufficient supply, and correct use of, airborne precaution PPE.

Right now, Australia is sitting somewhere in the middle. National guidance needs to be urgently updated to reflect safest practice and acknowledge what we’re learning about the airborne spread of the virus.

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What is PPE?

PPE is a crucial part of controlling exposure to hazards in all workplaces.

It includes items such as masks, respirators, face shields, gowns and gloves.

PPE is categorised into three tiers, corresponding to the type of hazard.

Level 1: standard and contact precaution PPE

This PPE limits exposure to standard contact hazards. Examples include face coverings and administrative controls such as hand hygiene, cough etiquette and physical distancing.

Level 2: droplet precaution PPE

This PPE prevents exposure to contact and droplet hazards. Examples include surgical masks, eye shields or goggles, long-sleeved gowns, and gloves.

Level 3: airborne precaution PPE

This PPE aims to prevent exposure to contact, droplet and airborne hazards. It includes N95/P2 respirators or powered air-purifying respirators with a P2 filter, eye shields or goggles, fluid-resistant gowns, double gloves, disposable head and neck wear, and protective footwear.

We’ve heard a lot about PPE in the context of coronavirus. But PPE isn’t just for health-care settings.

Current Australian guidelines

The national guidance on the use of PPE in hospitals during the COVID-19 outbreak has been written by the Infection Control Expert Group and endorsed by the Australian Health Protection Principal Committee.

The guidance doesn’t recommend universal airborne precaution PPE for health-care workers dealing with patients suspected or confirmed to have COVID-19. It only recommends level 3 protection for highly specialised procedures such as intubating a patient.

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A preprint in the Medical Journal of Australia has criticised the current guidance, noting it’s not aligned with increasing scientific evidence regarding airborne transmission of SARS-CoV-2 and is therefore inadequate to protect health-care workers.

Inadequate national guidance has led to an inconsistent and non-standardised approach to airborne precaution PPE across all health-care settings.

In the absence of strong national safety guidance, some hospitals and jurisdictions are making independent improved safety recommendations to their staff.

Why we need level 3

Transmission of SARS-CoV-2 occurs by direct contact with droplets and contaminated surfaces — but emerging data suggests it can also be spread by the airborne route.

An analysis of health-care worker deaths in the United Kingdom found none among wearers of level 3 PPE, suggesting airborne precaution PPE was protective.

A nurse stands in hospital corridor scrolling on her phone. She is wearing scrubs, a surgical mask and a hairnet.
Surgical masks don’t offer as much protection against COVID-19 as respirator masks.

Importantly, surgical masks are primarily designed to protect the environment from the wearer. They’re not designed to protect the wearer from respiratory pathogens.

A recent review found N95 respirators offered significantly better protection against viruses including COVID-19 than surgical face masks, while one study found N95 respirators provided 8-12 times more protection than surgical masks against small viral particles.

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In Australia, N95 is synonymous with P2 respiratory protection and refers to the filtration efficiency (so N95 means 95% of particles are filtered). But it’s the total inward leakage — what goes through and around the facemask — that’s the critical factor in determining the level of protection the wearer achieves.

To ensure total inward leakage is minimised, respiratory masks used under level 3 PPE must meet certain standards, including fit testing and the training of wearers in their use.

We need immediate action

SARS-CoV-2 is a highly contagious virus with the potential to cause significant ill health and death. In health-care settings, it should be classified as a lethal biohazard and managed accordingly.

The safest approach is to consider all people with confirmed or suspected COVID-19 in hospital, being transported to hospital or being tested for COVID-19 as being able to spread the virus via the airborne route. As such, the use of airborne precaution PPE with a correctly fitted N95/P2 respirator is essential.

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There’s also an urgent need for a national registry of health-care worker infections, containing data about the category of health-care worker, where the infection was acquired, severity of disease, hospitalisation, intensive care and death numbers.

This will give us a better understanding of the scope and specifics of the problem, and inform policy and prevention strategies.

Finally, adequate supply of airborne precaution PPE must be available throughout Australia to protect health-care workers from COVID-19.The Conversation

Alicia Dennis, Associate Professor MBBS, PhD, MPH, PGDipEcho, FANZCA, University of Melbourne and Jane L Whitelaw, Certified Occupational Hygienist, University of Wollongong

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Millions of products have been 3D printed for the coronavirus pandemic – but they bring risks

James Novak, Deakin University

With the COVID-19 pandemic, an urgent need has risen worldwide for specialised health and medical products. In a scramble to meet demand, “makers” in Australia and internationally have turned to 3D printing to address shortfalls.

These days 3D printers aren’t uncommon. In 2016, an estimated 3% of Australian households owned one – not to mention those available in schools, universities, libraries, community makerspaces and businesses.

A collection of desktop 3D printers in the Deakin University 3DEC lab.
James Novak

Across Europe and the United States, access to essential personal protective equipment (PPE) remains a concern, with nearly half of all doctors in the UK reportedly forced to source their own PPE.

In Australia, reports from March and early April showed hospital staff reusing PPE, and health-care workers sourcing PPE at hardware stores due to shortages.

The global supply chain for these vital products has been disrupted by widespread lockdowns and reduced travel. Now, 3D printing is proving more nimble and adaptable manufacturing methods. Unfortunately, it’s also less suited for producing large numbers of items, and there are unanswered questions about safety and quality control.

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Sharing is caring

One of the earliest examples of 3D printing being used for pandemic-related purposes is from mid-February. One Chinese manufacturer made 3D-printed protective goggles for medics in Wuhan. With 50 3D printers working around the clock, they were producing about 300 pairs daily.

Designers, engineers, students, manufacturers, doctors and charities have used 3D printing to produce a variety of products including face shields, masks, ventilator components, hands-free door openers and nasal swabs.

Many designs are freely shared online through platforms such as the NIH 3D Print Exchange. This US-based 3D printing community recently partnered with the Food and Drug Administration (FDA) and the Department of Veterans Affairs, to assist with validating designs uploaded by the community. So far, 18 3D-printable products have been approved for clinical use (although this is not the same as FDA approval).

Such online platforms allow makers around the world not only to print products based on uploaded designs, but also to propose improvements and share them with others.

Makers are using various ways to 3D print medical supplies during COVID-19.

Just because you can, doesn’t mean you should

In a public health crisis of COVID-19’s magnitude, you may think having any PPE or medical equipment is better than none.

However, Australia’s Therapeutic Goods Administration (TGA) – our regulatory body for medical products – has not yet endorsed specific 3D-printed products for emergency use during COVID-19. Applications for this can be made by manufacturers registered with the TGA.

However, the TGA is providing guidelines which designers, engineers and manufacturers are working with. For example, Australian group COVID SOS aims to respond to direct requests by frontline medical workers for equipment they or their hospital need. So, local designers and manufacturers are directly connected to those in need.

3D printing provides a means to manufacture unique and specialised products on demand, in a process known as “distributed manufacturing”.

Unfortunately, compared with mass production methods, 3D printing is extremely slow. Certain types of 3D-printed face shields and masks take more than an hour to print on a standard desktop 3D printer. In comparison, the process of “injection moudling” in factory mass production takes mere seconds.

That said, 3D printing is flexible. Makers can print depending on what’s needed in their community. It also allows designers to improve over time and products can get better with each update. The popular Prusa face shield developed in the Czech Republic has already been 3D printed more than 100,000 times. It’s now on its third iteration, which is twice as fast to print as the previous version.

A Prusa RC3 face shield 3D printed on a desktop 3D printer.
James Novak

Opportunity vs risk

But despite the good intent behind most 3D printing, there are complications.

Do these opportunities outweigh the risks of unregulated, untested product used for critical health care situations? For instance, if the SARS-CoV-2 virus can survive two to three days on plastic surfaces, it’s theoretically possible for an infected maker to transfer the virus to someone else via a 3D-printed product.

Medical products must be sterilised, but who will ensure this is done if traditional supply chains are bypassed? Also, some of the common materials makers use to 3D print, such as PLA, aren’t durable enough to withstand the high heat and chemicals used for sterilisation.

And if 3D-printed products are donated to hospitals in large batches, identifying and treating different materials accordingly would be challenging.

For my research, I’ve been tracking 3D-printed products produced for the pandemic. In a soon-to-be-published study, I identify 34 different designs for face shields shared online prior to April 1. So, how do medical practitioners know which design to trust?

If a patient or worker is injured while wearing one, or becomes infected with COVID-19, who is responsible? The original designer? The person who printed the product? The website hosting the design?

These complex issues will likely take years to resolve with health regulators. And with this comes a chance for Australia – as a figurehead in 3D printing education – to lead the creation of validated, open source databases for emergency 3D printing.

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The Conversation

James Novak, Postdoctoral Research Fellow – Additive Manufacturing, Deakin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Supplies needed for coronavirus healthcare workers: 89 million masks, 30 million gowns, 2.9 million litres of hand sanitiser. A month.

Katherine Gibney, The Peter Doherty Institute for Infection and Immunity and Caroline Marshall, University of Melbourne

In three short months, more than half a million cases of the novel coronavirus, COVID-19, have been reported worldwide.

The US now has the highest number of COVID-19 cases worldwide and Italy has reported more than twice as many COVID-19 related deaths as China. Deaths from COVID-19 in Spain have surpassed China in recent days, and it won’t be long before France and the US follow suit. COVID-19 has well and truly taken hold in the West.

While most people are being encouraged (or ordered) to stay at home to reduce the spread of COVID-19, this is not an option for frontline healthcare workers.

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Healthcare workers have been infected at an alarming rate

In countries whose health infrastructure has been overwhelmed by the sheer volume of severe COVID-19 cases, healthcare workers have been infected at an alarming rate.

In Italy, more than 6,000 healthcare workers have been infected, making up 9% of the total COVID infections. In Spain, 17% of female COVID-19 cases are healthcare workers (12% of all COVID-19 cases are healthcare workers). More than 2,000 healthcare workers in China had laboratory confirmed COVID-19, with 88% occurring in the worst affected Hubei province.

In Australia, COVID-19 patients are cared for in single rooms where available. However, soon it will be necessary to care for COVID-19 patients in wards and ICUs alongside other COVID-19 patients – known as “cohorting” – as a patient with COVID-19 cannot catch the same disease from another patient sharing their ward.

COVID-19 is transmitted primarily by virus-containing droplets that are expelled when an infectious person sneezes, coughs or talks, contaminating others in close face-to-face proximity and nearby surfaces. This underlies the general advice to stay more than 1.5 metres away from others, practice good cough etiquette and hand hygiene, and avoid touching your face with your hands.

The number of masks, goggles, gloves and gowns we’ll need is staggering

Healthcare workers use personal protective equipment (PPE) – masks, goggles, gloves and gowns – and clean surfaces to prevent transmission in hospital.

Some procedures that are required when caring for critically ill patients can generate smaller virus-containing particles called aerosols, which can be inhaled.

In circumstances where aerosols could be generated, PPE requirements include use of a respirator mask (also known as a P2 or N95 mask) and a negative room pressure, where a slight vacuum is created to prevent contaminated air escaping the room.

The volume of PPE required to deal with the COVID-19 pandemic is staggering.

The WHO has estimated frontline healthcare workers will require at least 89 million masks, 30 million gowns, 1.6 million goggles, 76 million gloves, and 2.9 million litres of hand sanitiser every month during the global COVID-19 response.

Hoarding and misuse of masks puts healthcare workers at risk

The WHO has also noted panic buying, hoarding and misuse of PPE are putting lives at risk from COVID-19 and other infectious diseases.

Healthcare workers are most at risk if they don’t use appropriate PPE when caring for a COVID-19 patient, such as before the COVID-19 infection has been recognised. This is how a number of unlucky Australian healthcare workers have already been infected with COVID-19 at work, including four from the Werribee Mercy Hospital in Melbourne’s outer west.

Early recognition of potential COVID-19 cases, and instituting precautions including isolation and use of PPE, will protect healthcare workers. Routine use of surgical masks in high-risk clinical settings such as emergency departments, ICUs and COVID-19 screening clinics is now recommended in many places.

PPE supplies in many countries have reportedly been exhausted, forcing healthcare workers to care for COVID-19 patients without adequate protection. Inappropriate and irrational use of PPE, including use of masks in situations where there is no risk of droplet or airborne transmission, accelerate consumption of a finite PPE supply.

The urgent work of securing more PPE

The federal, state and territory governments are working hard to secure enough PPE to prevent this scenario in Australia, including boosting domestic production and manufacturing capacity. Local industry has stepped up with companies previously making other products now making hand hygiene products and masks.

This is urgent work because it’s likely a rapid surge in COVID-19 cases would consume current PPE supplies quickly.

Crisis strategies being employed internationally to deal with mask shortages include prolonged use, re-use by a single healthcare worker, and use beyond the manufacturer designated shelf life, although these are not standard practice. Work is also taking place around sterilisation of masks for re-use by health care workers, which again is not standard practice.

Healthcare workers are also at risk if PPE is used incorrectly, due to inadequate training, inattention, or fatigue. Training healthcare workers in correct use of PPE is a critical part of our emergency response.

Like everyone else, healthcare workers are at risk outside work. In China, outside Hubei, the majority of healthcare workers’ infections could be traced to a confirmed COVID-19 case in the household. As community transmission of COVID-19 becomes more widespread in Australia, more healthcare workers will be infected at home and in the community.

When healthcare workers can’t work

It’s vital the healthcare workforce is maintained for the duration of the pandemic. Perversely, some of the actions taken to prevent COVID-19 transmission might result in healthcare workers’ workplace absenteeism. Often healthcare workers would work through a mild upper respiratory tract infection, but with the current heightened awareness they might not be doing this. All healthcare workers are being encouraged to present for testing if they have fever or acute respiratory symptoms such as sore throat, cough and difficulty breathing. They are usually unable to return to work until a negative COVID-19 test result is received and symptoms have resolved. This can take several days.

If a healthcare worker is exposed to a COVID-19 case when not wearing PPE (meaning they spend more than 15 minutes face-to-face or more than two hours in the same room as a case), they will be classed as a close contact and will be home-quarantined and unable to work for 14 days after they were exposed.

And carer responsibilities – either for someone unwell with COVID-19 or for children unable to attend childcare or school due to closures – will keep many healthcare workers away from work.

In the current climate, healthcare workers have been described as “every country’s most valuable resource.” Governments, employers and the public need to do everything they can to protect and support healthcare workers throughout this pandemic.

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The Conversation

Katherine Gibney, NHMRC early career fellow, The Peter Doherty Institute for Infection and Immunity and Caroline Marshall, Associate Professor, Infectious Diseases, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.