COVID-19: Face masks are no silver bullet, but they're important

The second wave of COVID-19 in Victoria has resulted in the state's Chief Health Officer mandating that “adults living in areas under stage three restrictions wear a face mask when outside ... if it is difficult to keep 1.5 metres apart from other people”.

Read more: Ten postcodes are back in stage three coronavirus lockdown – here's what that means

This is a good and sensible; however, despite  the populist belief that masks may be the panacea, the wearing of masks in public needs to be put into context.

The recommendations to prevent the spread of COVID-19 have been very clear from the outset. Stay at home if you're unwell, maintain 1.5m distance, practise good hand hygiene, and get tested if you have symptoms.

Read more: Metropolitan Melbourne, Mitchell Shire return to lockdown – this is just how vigilant we have to be until a COVID-19 vaccine is found

In regard to wearing masks in public, guidance has always been related to the prevalence of infection in the community. For the most part, the prevalence of COVID-19 in the Australian community remains low. Hence, a recommendation to wear a mask in public was not warranted. However, now that the prevalence of community transmission in Victoria has increased, the recommendation has been scaled up. This isn't a change in policy, merely a reflection of the increased prevalence.

It's also worth putting Australia’s prevalence into an international context.

Masks are more commonly worn in the US, and yesterday the UK government announced masks are mandatory when in shops.

So why shouldn’t Australia automatically follow suit?

This is why: The number of COVID-19 cases in the US is 10,500 per million population; in the UK it's 4300. In Australia, it's 390.

The number of deaths in the US is 418 per million population. In the UK, it's 660. In Australia, it's four. In short, by comparison, the prevalence of COVID-19 cases in Australia remains remarkably low.

Nevertheless, this is not a time for complacency, and we must remain vigilant. Victoria’s second wave has not peaked, and the number of new cases now appearing in NSW is worrying, so we need to follow the recommendations. In Victoria, this includes wearing a mask when we can’t maintain physical distancing.

Why the mask?

COVID-19 is spread through close contact with an infectious person, and contact with their droplets. A mask will assist in stopping those droplets entering your mouth and nose. Probably more important, though, is that if you have undiagnosed COVID-19 and cough, the mask will greatly suppress the dispersion of droplets to others.

Essentially, there are two type of masks – single-use disposable, and reusable cloth. Each has its pros and cons, and choice will also be influenced by availability and cost. So, there's a few things to remember when wearing a mask.

First, as noted in the recent systematic review published in The Lancet, a mask alone will not prevent infection. You must continue to follow all of the other recommendations – hand hygiene, maintain 1.5 metres whenever possible, stay at home if you aren't well, and get tested and isolate if you have symptoms.

Second, a mask will only be effective if you wear it properly. They aren't chin slings, earrings, or fashion accessories. Wear them with purpose. The mask needs to fit snugly and cover both your mouth and nose at all times. Masks can be uncomfortable to wear. If you're going to wear one, you also need to avoid fiddling with it, and touching your face, eyes, nose, and mouth, otherwise you might contaminate yourself.

Third, you need to be careful when putting on and taking off your mask. The Victorian Department of Health and Human Services has an excellent resource on mask protocols. Here are some key points:

• Wash or disinfect your hands (with alcohol-based disinfectant) before you put on your mask.
• Avoid touching the mask while you're wearing it.
• Carefully remove the mask using the loops or ties. Don't touch the front of your mask. If it's a disposable mask, place it in an appropriate waste container; if it's reusable, place it into a plastic bag and take it home to wash.
• Then wash or disinfect your hands (with alcohol-based disinfectant).

COVID-19 continues to present us with many challenges. Evidence continues to be scanned on a daily basis, our knowledge evolves, and guidelines are updated.

Prevalence in Australia may wax and wane for some time, and, accordingly, recommendations will be scalable. Recommendations only work if they're followed. Right now, metropolitan Melbourne and the Mitchell Shire are in stage three, and an upgrade to stage four isn't out of the question. Let’s follow stage three. We’ve done it before, we can do it again.