Masks are better than face shields: Experts say airborne droplets can get around the visors 

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Victorians must now wear fitted face masks instead of bandannas, scarves, plastic face shields as masks have been deemed more effective at stopping droplet spread.

Premier Daniel Andrews made the announcement Sunday ahead of Monday’s Step Two lifting of coronavirus restrictions across Victoria.

It means that bandannas and scarves are no longer enough – Melburnians must also wear a face mask with them or instead of them.

YES: face shield with a mask underneath

NO: face shield with no mask

Pictured left: A face shield can be worn with a mask for extra splatter protection. Right: A face shield without a mask is banned in Victoria as of Monday as it lets in too many aerosol particles

As far as transparent plastic face shields go, Victorians must also wear a face mask underneath.

‘Face shields don’t meet the test of covering your nose and your mouth,’ Mr Andrews said on Sunday. 

‘You can wear a face shield if you want to in terms of your eyes, but it would need to be accompanied by a mask and we would recommend a two-ply mask. A shield is akin to not wearing a face covering.’  

Victorians will risk a fine of $200 if they do not wear a face mask while out.

WHY THE RULE CHANGE?

Face shields were never meant to be used without also wearing a face mask.

Professor Raina MacIntyre, head of the Biosecurity Research Program at the Kirby Institute at the UNSW said they are not appropriate protection in the community.

‘In Switzerland, where hotel staff could choose a mask or a shield, only those wearing a shield got infected,’ she told Daily Mail Australia on Monday.

‘The virus is spread by respiratory aerosols, which are breathed directly in, unfiltered, when wearing a shield.’  

A man walks past an outdoor photography exhibition of healthcare workers in Melbourne last Tuesday. Face masks are now mandatory in Victoria - a plastic face shield is not enough

A man walks past an outdoor photography exhibition of healthcare workers in Melbourne last Tuesday. Face masks are now mandatory in Victoria – a plastic face shield is not enough  

Switzerland’s hotel coronavirus outbreak prompted the country’s health department to declare face shields ineffective in July. 

Deakin University epidemiologist Catherine Bennett said masks sit more closely to the face and stop the majority of particles leaving or entering someone’s mouth or nose.

This decreases the risk that the droplets and particles of other people will reach the mucosal lining in your nose and mouth as you breathe.

It also reduces the amount of your own droplets in the air where they might infect others.   

‘If there is too much gaping at the sides, the particles or the droplets can make their way around the edge of the covering,’ she told the Herald Sun.

‘As soon as you having gaping holes, it is not effective. It’s that marginal gain you get in terms of reduced risk of transmission.’ 

WHY DON’T FACE SHIELDS WORK?

Face shields are only for direct splatter protection, for example if someone coughs directly in your face, Professor MacIntyre said.

‘They will not block aerosols, which can be breathed in, unfiltered, through the gaps around the edges,’ she told Daily Mail Australia.

‘Shields are designed to be used as an adjunct to masks, not as an alternative.’

Bandannas such as this one worn by a man at Edithvale Woolworths, Melbourne, in August, are now banned unless you are also wearing a face mask underneath

Bandannas such as this one worn by a man at Edithvale Woolworths, Melbourne, in August, are now banned unless you are also wearing a face mask underneath

Professor MacIntyre said surgical or cloth face masks are not designed to filter aerosols. Instead they are designed as a physical barrier.

‘However, three layers or more in a cloth or surgical mask can be a good filter, as long as the mask fits closely around the face without any gaps,’ she said.

‘This then forces air through the face piece, which acts as a filter.’

Professor MacIntyre and other scientists conducted a study which was published in the medical journal Thorax, showing how much difference extra mask layers can make.

The team found a single-layered cloth mask reduced droplet spread somewhat but was not as good as a double-layered cloth mask.

A three-ply surgical mask was better than both, the research showed.    

‘We did not test more than two layers, but generally, more layers are better,’ the researchers wrote in The Conversation in July. 

‘For example, a 12-layered cloth mask is about as protective as a surgical mask, and reduces infection risk by 67 per cent.’

IS ANYTHING 100 PER CENT EFFECTIVE?

Coronavirus infects a person when viral particles come into contact with the mucosal membranes (the wet parts) in the nose, eyes and mouth.

Droplets with the viral particles are sprayed out of the mouth and nose when an infected person talks, laughs, sings, shouts, breathes, coughs and sneezes. 

The heavier droplets fall to surfaces where they can be picked up on your hands and fingers – and when you touch your eyes, nose or mouth, the virus on your hands infects the mucosal membranes.

The smaller, lighter aerosolised particles hang in the air where you can breathe them in, causing infection.  

According to a WHO-commissioned study on the effect of physical distancing, masks and eye protection against covid-19, no barrier is 100 per cent effective. 

Professor MacIntyre said the study,  published in The Lancet, found even respirators only reduce the risk of infection by 95 per cent.

Face masks reduced the risk of infection by 67 per cent and physical distancing of one metre reduces the risk by 82 per cent, according to the study.

‘The bottom line is no intervention gives you 100 per cent protection, you have to use them in combination to reduce the risk,’ Professor MacIntyre told Dr Norman Swan on the ABC’s health report in June.

‘Until the time that we can vaccinate people, you really have to use these interventions in combination.’ 

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