Wearing a mask that covers both your mouth and nose is crucial to protecting yourself (and others) from coronavirus, because the nostrils are particularly vulnerable to infection, new research shows.
Although its coronavirus’s devastating effects on the lungs that land patients in the ICU, University of North Carolina (UNC) scientists found that the virus typically first lodges itself in the tissue inside the nose and travels down the respiratory tract from there.
The virus does not establish itself or make copies of itself as well in the throat, but can make its way from the nose into the lungs of some people at night while they sleep.
With strong evidence that the nose is coronavirus’s first target and best breeding ground, the scientists say that wearing a mask is key – and rinsing out your nostrils may help reduce the risk that the virus will reach the lungs and cause life-threatening pneumonia.
WRONG! Nostrils are full of receptors that the virus targets and is a far more fertile ground for coronavirus to multiply before traveling down to the lungs, making wearing a mask over the mouth and nose essential, University of North Carolina researchers warn. An NYPD officer wore his mask incorrectly during a Black Trans Lives Matter protest in Brooklyn (file)
In their research, published in the scientific journal Cell, the UNC researchers studied the microbiology of tissue samples taken from nostrils, trachea and lungs.
They also tested what happened to cells from each of these tissue types when they were put in the petri dish ring with SARS-CoV-2, the virus that causes COVID-19.
In the first part of their study, they found a bellwether for how coronavirus gets into the body.
Unquestionably, the inside of the nose – specifically, cells known as the nasal epithelium – was the area most ripe for infection.
That’s these cells’ surfaces are densely packed with ACE2 receptors.
‘Every virus has a key on the surface – this one is called the spike protein – and this key opens a lock, and the lock is a [ACE2] receptor, and your nose is just loaded with receptors for this virus,’ explained co-lead study author, Dr Richard Bouche during an interview with DailyMail.com.
‘So if this virus impacts there, it finds very fertile ground for infection.’
Not only are there lots of ‘keys’ that fit the virus’s ‘key,’ Dr Boucher and his team found that it can replicate itself far more prolifically in nasal tissues than in other tissues.
‘It really blooms i the nasal surfaces,’ said Dr Boucher.
‘It really is the nose that is the engine for this thing, so you have to protect it.’
And the best way to do that at present is the simplest one: wear a mask, and wear it correctly, covering both your nose and mouth (the latter of which is a far less vulnerable or desirable target for the virus).
Studies have suggested that wearing a mask reduces coronavirus transmission by up to 80 percent.
A nurse from Oregon assisting during the pandemic in New York City wears two masks covering her nose. Within four days in the nose, the virus can make 10 million copies of itself
Still, a stroll down any city street in the US or other nations will show clearly that many people are either not wearing masks, or wearing them over only their mouths, or slung (uselessly) around their chins.
‘I think if they thought about it, they would understand it completely,’ says Dr Boucher.
‘The nose has just got to be protected, so I’m a mask, mask, mask fan.’
If it isn’t, the virus gets into the nostrils and multiplies prolifically.
‘After three of four days, there are 10 million copies per milliliter of secretions on cultured nasal surfaces, where as you find a thousand to 10,000 at most in deeper lung tissue – so there’s 1,000-fold more in the nose,’ Dr Boucher explained.
‘The nose is clearly the fertile ground for the virus.’
How it goes from the nose to deeper lung tissue where coronavirus poses a real, deadly risk, is a subject of speculation, but Dr Boucher believes it most likely happens, nightmarishly, at night as people sleep.
Most of us are able to clear mucus that drips down the nasal passageway into the throat or, incorrectly, into the windpipe.
‘But at night, if you’re older, or chubby or have diabetes’ – all of which sometimes cause dysfunction in the muscles and mechanisms that open and close the airway – ‘often you get some of that oral material that went down the wrong way, and that wrong way is down to the lung,’ said Dr Boucher.
‘Suddenly you have this huge bowl of virus that goes down into the lung and that’s enough to trigger infection.
‘That’s very consistent with the fact that the most at-risk people are elderly, obese or diabetics.’
In addition to wearing a mask to prevent the virus from getting into the nose in the first place, the UNC research suggests that washing virus out of your nose – literally – before bed might help prevent it from traveling into the lungs overnight.
Dr Boucher primarily treats children with cystic fibrosis, whose lungs are highly infection prone, and for whom even a common cold can prove deadly.
Physicians like Dr Boucher sometimes advise these patients to do neti pot or high volume rinses of their noses at night to avoid sinus infections.
Although it would be an uncomfortable nightly practice, Dr Boucher says that it might ‘wash out 10 or 50 million viruses’ if you think you’ve been exposed.
Because coronavirus is encased in a protective lipid, or oily, ‘envelope,’ simple detergent, like baby shampoo, can actually break the virus’s bubble open and kill it.
So UNC, as well as Vanderbilt University, are testing whether a soapy nose rinse could lower risks of coronavirus infection.
‘What we know now is a high volume nasal lavage [with water alone] is safe and everything in life is risk-benefit and do no harm,’ Dr Boucher said.
However he adds that the a soapy wash still needs to be tested in the clinical trials to know if it’s completely safe and works.