Unmasking myths
No harm, and failing to wear one is as ‘antisocial’ as drunk-driving
THE frantic woman made a controversial argument as to why Palm Beach, US residents should not be forced to wear face coverings: “I don’t wear a mask for the same reason I don’t wear underwear,” she said. “Things gotta breathe.”
Her proclamation at the County Board meeting earlier this month was met with a chorus of whoops and cheers – the rest of the room, it seems, agreed.
A video of the hearing, at which commissioners unanimously voted to make wearing masks in public mandatory, has gone viral, and while some commentators poke fun at her antimask stance, others appear convinced by her argument.
Yes, tight face coverings can seem restrictive, but are they harmful?
The claims, often made in widely shared social media posts, sound alarming. Masks increase the risk of catching Covid-19; they suppress the immune system; wear one long enough and they’ll push up your blood pressure, starve the body of oxygen and allow carbon dioxide to build to toxic levels.
No wonder there are concerns, especially as face coverings are now compulsory.
After a study found that face coverings reduce the risk of coronavirus transmission by a third, president of the Royal Society, Professor Venki Ramakrishnan, suggested that failing to wear one is as “antisocial” as drunk-driving or not putting on a seatbelt. “If all of us wear one, we protect each other and thereby ourselves,” he said.
Is there evidence that a mask can be harmful? And are some people, particularly those with respiratory conditions, at additional risk from wearing one?
The claims are, on the whole, nothing but fake news. The most outlandish have spread from America, where there is growing opposition to mask-wearing despite a terrifying surge in coronavirus cases. There are groups who refuse to wear them, and have staged demonstrations about their “right to breathe”.
Some mask concerns do have a scientific basis, but they are mostly linked to studies on a specific type known as a N95 respirator, according to Paul Hunter, professor of medicine at the University of East Anglia.
These are tightly fitted to the face and are worn by surgeons during operations on bones and joints, which generate large amounts of airborne particles. They are also highly effective at filtering out tiny molecules, including viruses such as Covid-19, so some people have taken to using them.
One of the main claims on social media is that masks cause a toxic build-up of carbon dioxide in the blood, known as hypercapnia.
This happens when someone breathes in recycled air – usually in confined spaces without ventilation – reducing oxygen and increasing CO2 levels. It causes breathlessness, headache, confusion and, in extreme cases, irregular heartbeat. One small study found nurses wearing N95s on a 12-hour shift had “significantly elevated” CO2 levels and reported headaches and feeling short of breath. But these symptoms were not significant enough to be considered hypercapnia.
The US Centers for Disease Control and Prevention said any build-up of CO2 would be unlikely in everyday use outside hospitals, and could be avoided byletting some air in. The same effects are not linked to normal surgical or cloth masks.
Other claims link masks to hypoxia, or reduced oxygen intake. One study of blood oxygen levels in surgeons before and after performing operations found levels of oxygen were reduced the longer they wore a mask. Again, these have not been linked to normal mask wearing.
The World Health Organization is also clear: face masks of a breathable material, worn properly, will not lead to health problems.
Another claim circulating on Instagram and Facebook is that wearing a mask makes catching coronavirus more likely, because the material “traps” infected droplets.
Epidemiologist Professor Keith Neal, at the University of Nottingham, says this is nonsensical. “The mask is to stop you spreading it – you can’t infect yourself if you are already infected,” he says.
However, Hunter warns that it is important to regularly wash cloth masks and to use surgical masks only once. “Particles of the virus might get trapped in the mask. It could spread to someone else if they handle it.”
What about claims that masks suppress the immune system, making infections more likely? Unsurprisingly, there is no evidence for this.
“Masks may stop germs getting into your mouth or nose, so your immune system doesn’t have to kick in, but this doesn’t mean it is being suppressed,” Neal says.
As for suggestions that face coverings can cause heart palpitations, and even raise blood pressure, this is likely to be caused by the psychological effects of wearing a mask.
But what about those with medical conditions such as asthma?
Many won’t feel any effects from wearing a mask, says Jessica Kirby, head of health advice at the British Lung Foundation. “But it can be a barrier to breathing for some people, which causes anxiety and in turn worsens breathing further.”
“Social media platforms need to get a grip on misinformation, including deleting the accounts of persistent offenders,” says Neal. |