Cloth masks quickly became a staple of the pandemic, a bright splash of colour in otherwise grim times.
However, the humble face covering is in danger of becoming Omicron's latest casualty.
In the US, a number of leading health experts are urging people to upgrade from cloth masks to N95s, or similar products, amid concerns that cloth masks just don't cut it against the highly virulent COVID-19 strain.
Some US buildings, such as the famed Mayo Clinic health centre, won't let people inside if they're wearing a bandana or cloth mask.
As the new variant pushes cases to record highs, 1.4 million Americans contracted COVID 19 on Monday, the highest daily count of any nation so far, according to Johns Hopkins University.
"Omicron is such an incredibly infectious agent, probably the most contagious pathogen on Earth," said Lawrence Gostin, professor of global health law at Georgetown University and the director of the World Health Organization Center on Global Health Law.
"A cloth mask is doing virtually nothing at this stage.
"Against Delta, it was only about 20 to 30 per cent effective, if that. And certainly, with Omicron, it has negligible effectiveness."
Professor Gostin said people need to ditch their cloth masks now in favour of a more-effective face covering.
"[They are] virtually useless against this kind of airborne aerosolised pathogen. And even surgical masks aren't as effective as they need to be."
"The truth is that we have very good masks. They're available. You can wear them appropriately. And they're highly protective."
Which masks are best?
Understanding the various options and array of letters associated with the higher-grade products can be confusing.
N95 masks, also referred to as respirators, are certified according to US standards.
In Australia, an N95 is sometimes referred to as a P2 mask, and is considered the best option on the market.
But you might see other options on the shelves or online.
US Health experts are urging the public to opt for three-ply surgical masks or N95 masks, which offer more protection against the highly contagious variant. (AP: Ted S. Warren)
KN95s should meet Chinese specifications, and KF94s, which have a slightly different design, are the Korean standard equivalent.
Both KN95s and KF94s — assuming they are the genuine — should, in theory, provide a comparable level of protection as the N95.
The masks are made from multi-layered interwoven synthetic material and filter out or capture about 95 per cent of airborne particles.
That means if one of these masks is worn correctly, they will provide a very high level of protection against exposure to the virus.
But what if you can't find an N95 at your local pharmacist?
The surgical option
Experts say the next best option is a multi-layered medical grade surgical mask, not a paper one.
But there's one important caveat: It must fit well.
While surgical masks can be effective, experts warn that a tight fit is key to protecting yourself from COVID-19. (Reuters: Shannon Stapleton)
"Let's talk about what are the two qualities that we look for in a mask," said Sabrina Assoumou, an infectious diseases doctor at Boston Medical Centre.
"The first one is filtration, and the second one is fit," she said.
Since surgical masks are usually one size, there are often gaps at the side, which dramatically reduce their effectiveness.
But these can be reduced by simple hacks such as knotting the ear loops.
What about double masking?
Putting a cloth mask on top of the surgical mask can also help to a certain extent.
Double-masking was popular in the US for a time last year, but Dr Assoumou said it's wrong to assume the cloth mask is increasing protection.
What it's doing is ensuring the surgical mask does its job properly with a better seal around the nose and mouth.
"You're trying to get the best of both worlds," she said.
US President Joe Biden was a big fan of double-masking during the 2020 presidential election. (Reuters: Tom Brenner)
Sabrina Assoumou also advocates strongly for a move away from cloth masks.
"I would say to anyone who's still using a cloth mask, please seriously consider upgrading your mask to at least a medical grade surgical mask that fits well," she said.
The infectious diseases doctor said she's frustrated that the Centres for Disease Control and Prevention (CDC) hasn't recommended a change in mask practices.
"I would welcome more clear messaging about upgrading our masks," she said.
"It's certainly something that I'm recommending to my patients, to my loved ones, and I don't want it to be that you only get access to this information if you're connected to a health worker."
How to spot a fake
At the beginning of the pandemic, the use of N95s was discouraged to allow supplies to go to frontline health workers.
These days they are much more widely available but so, too, are a multitude of fakes.
The CDC has published information about how to spot a fake, including tips as simple as being on the lookout for incorrect spelling.
Experts say to be on the lookout for fakes when purchasing an N95 or P2 mask. (Reuters: Carlos Osorio)
Australia's Therapeutic Goods Administration is also conducting its own review.
Checking whether the mask you have purchased is genuine can still be tricky, but the lists of approved products is being frequently updated.
"It's been completely confusing," said Professor Gostin.
"It's not just confusing in the messaging. You've got very little regulation going on about what claims companies can make."
Some basic tricks to test whether your mask is working include trying to blow out a candle while wearing it. You should have difficulty.
You can also put on your mask and hold out your hand in front of you and to each side while blowing to see if you can feel the air.
You can also hold your mask up to a lamp to check if too much light is not getting through.
To reuse or not to reuse
Medical staff are advised not to reuse N95s, but for the general public, most experts agree the masks can be re-worn several times.
"N95s, KN95s and KF94s could probably be reused for about a week if not soiled or wet," said Sabrina Assoumou.
Most experts agree it's okay to reuse your respirator masks a few times. (Reuters: Elizabeth Frantz)
If you're worried about the environmental impact of reverting back to disposable masks, experts say there is some light at the end of the tunnel.
Lawrence Gostin said the world will one day reach a time when the SARS-CoV-2 virus is endemic.
At that point, he said, there would be more treatments available for those who became seriously ill and masks would not be necessary in every situation.
"There will be one day — and it won't be that far away — where the goal will be really just to prevent people from being hospitalised, from getting very sick and dying," he said.
Dr Assoumou agreed that wearing masks would not have to be forever.
"I am hoping that cases are going to start coming down and then we'll be in a place where we don't all have to be wearing all this protective gear and all these masks all the time," she said.
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