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Evidence suggests universal mask-wearing may help to curb COVID-19 spread: study

Research 20 Jul 2020
Woman wearing mask

Wearing of masks by everyone may help to reduce droplet transmission of the virus, says a Sydney researcher.

People should be encouraged to wear face masks in public to limit the devastating effects of COVID-19, says a researcher at the George Institute for Global Health in Sydney.

Dr Anthony Paulo Sunjaya, a doctoral researcher in the respiratory division of the Institute, believes there is strong evidence to suggest that wearing masks can be helpful in limiting the spread of the virus, especially in public spaces, on public transport, and in areas of high-density living such as public towers.

Physical distancing and maintaining hand hygiene have been recommended as key strategies to reduce transmission of the virus, say the authors. Wearing a mask, adds Dr Sunjaya, should be considered as another layer of protection.

“I would recommend using reusable masks and, if possible, to use more than one mask a day, maybe two or three,” he says. “I would also recommend putting the used masks into a ziplock bag until you are ready to wash them.”

Victorian Premier Daniel Andrews has announced mask-wearing in public will be compulsory for all people in Melbourne and Mitchell Shire from this Thursday, following the explosion in COVID-19 cases that saw the city put into a second lockdown. Mask wearing is increasingly being made compulsory or recommended in countries across the globe including the US, Germany, Spain, Greece, Italy, Israel, France and the UK.

Dr Sunjaya, who co-authored a commentary paper called Rationale for universal face masks in public against COVID-19, published in the journal Respirology in April, says the case for wearing masks has become even stronger in the months following the paper’s publication. To date, nearly 13.5 million people worldwide have been infected by the virus and it has caused close to 580,000 deaths.

In the paper, Dr Sunjaya and his co-author Dr Christine Jenkins point to some of the difficulties in battling COVID-19. Some reports, they say, have suggested that up to 75% of those infected may be asymptomatic – not showing any symptoms – or have mild symptoms. However, that does not stop them from infecting others.

Droplet spread has been identified as the primary cause of human-to-human transmission. The authors say that laboratory studies have shown that droplets can travel distances as great as seven to eight metres – a lot further than the one to two metre recommendation for physical distancing in many countries, including Australia (1.5m).

What may be even more concerning is that particles, or aerosols, can remain suspended in the air for some time before finally settling on surfaces. These particles, which may carry the virus, are so tiny that they cannot be seen by the naked eye. It is possible that people could inhale those microdroplets.

No study has been done to test the effectiveness of masks against COVID-19. However, the authors cite a case-controlled study during the SARS outbreak in Hong Kong in 2003, which suggested that frequent use of masks (mainly surgical) in public places could be protective by 64%.

United nations covid 19 response pjo B 6l Ub Lo unsplash

The authors admit that a universal uptake of masks could put pressure on their supply to health workers on the frontline who are at greatest risk of infection, so suggest homemade cloth masks could be the solution.

They quote one study that revealed homemade masks – made by using a pillowcase or a 100% cotton shirt – were about 33% as effective as medical masks, but still helpful in reducing the number of microorganisms expelled compared to no protection.

However, a recent study comparing homemade masks made from four layers of kitchen paper and one layer of cloth with N95 masks and surgical masks reported comparable results of 95.1% versus 99.98% and 97.14%, respectively, in blocking avian influenza aerosols made by a nebuliser.

Dr Sunjaya says that in real-world conditions, the effectiveness of the handmade masks would probably be less, but nonetheless would still be helpful.

Masks – what you need to know

  • Do I need to wear a mask? Wearing of masks in public is compulsory for all people aged 12 and over in Melbourne and Mitchell Shire from this Thursday. This ABC news story has the latest information on mask use and regulations.
  • How do I correctly use a mask? This video from the Royal Melbourne Hospital is essential viewing. It shows how to correctly put on, wear and remove face masks.
  • Can I make my own masks? Yes. This story in The Age includes instructions on how to make your own masks.
  • Where can I buy masks? Single-use masks are available to buy from chemists and many online suppliers. If you would like to buy re-usable masks and also support women from migrant, refugee or asylum seeker backgrounds, they’re available from Melbourne organisation Sisterworks.
  • What else can I do to stay safe? You still need to ensure you remain at least 1.5 metres away from other people when out in public. Sneezing or coughing into your elbow, washing your hands often and/or using hand sanitiser, and avoiding handshakes or hugs remain essential to help keep you safe from COVID-19.