14 Sep 2021

Masking out the virus

From The Detail, 5:00 am on 14 September 2021
School-age children in medical masks. portrait of school children

Photo: 123RF

As Covid community cases fall, and New Zealand cautiously cycles back its alert levels, one highly visible precaution is staying – mask wearing.

Level 2 with a twist means face coverings must be worn in most public venues such as shops, malls and libraries, places such as bars and restaurants (unless you’re actually eating), on public transport, and in some instances, at work.

It’s possible that there is no end in sight for the appearance of the mask. Today on The Detail, we have a look at the pros and cons for that.

Epidemiologist Dr Michael Baker says ultimately mask wearing is all about the transmission of what is a respiratory virus.

“If we stop that …. there is no more pandemic, there’s no outbreak, it finishes,” he says.  

“If it was a food-borne disease you would be preventing people eating contaminated food; if it was say a skin infection, you would look at how it’s getting from one person’s skin to another by direct contact.

“So this is a respiratory pathogen, it basically latches onto cells in your upper airways and viruses have to attach to receptor sites, they have to get inside the cell, they hijack the machinery of the cell to make more copies of themselves, they kill the cell and then you get all sorts of other effects.

“It’s evolved to transmit from person to person as a respiratory infection and the main way it does that is on respiratory droplets in aerosols.

“People generate these just by breathing, by talking, laughing, singing, shouting … and coughing and sneezing.

“All of those activities they fire out these little droplets that have a limited range.”

Try to think of it as a can of fly spray – fire it out and the aerosol eventually fills a whole room.

Masks provide two barriers against the virus getting from the source person to others in the room – even quite a basic mask stops the droplets getting into the room; and mask wearers have a barrier against the entry of the virus particles getting in.

Our everyday masks obviously aren’t as good as hospital grade ones, “but it’s better than nothing,” says Baker.

At the start of the pandemic masks were looked at as being designed for health care workers, as PPE. 

“Initially in the pandemic many of us were thinking ‘it’s not really practical for the public to have that level of protection’. We felt we had to preserve our masks for the healthcare system because our supply was limited.”

But mass-masking, or universal masking, is another way of looking at it – one designed to dampen down transmission. Here’s where fabric masks have a use, a cheap way of approaching the issue and which won’t run the risk of running out of stocks.

Baker recommended the increased use of masks in Level 2, the first level below the ‘stay at home’ orders designed to stamp out the outbreak.

“The lower levels provide additional backup if we get an unexpected case occurring in the community,” he says.

“We know the system is not perfect. There’s a chance (someone) may have escaped screening and other measures, and may be asymptomatic for example.

We have to try and put a barrier in the way of the virus in case people are infectious. Masking is a very useful step.”

It’s certainly more effective than physical distancing, which we now know doesn’t really provide the protection we thought it did at the start of this pandemic.

And – “you can always tell when someone’s wearing a mask – but you can’t tell if they’ve washed their hands.

“If mask use allows us to come out of lockdown faster – it’s worthwhile.”

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Photo: .