Floor tiles, signs, and posters urge us to “KEEP A SOCIAL
DISTANCE,” while arcane one-way systems stop us from passing to one another.
Sinks have been taped up, just in case we get too close while carrying out
all-important hand-washing.
اضافة اعلان
It’s a picture being seen in workplaces and public spaces up
and down the country.
The UK’s government advice, for almost a year now, is that
we should all stay at least two meters away from anyone we don’t live with.
The idea is that, if we are far enough apart, we’ll avoid
transmitting the virus. And if we can’t be, there’s always those plastic
screens that seem to have been erected everywhere to protect us. But is it that
simple?
Social distancing policies have been instigated by many
businesses at the start of the pandemic. And as Britain edges out of lockdown,
they remain unchanged.
But the science has moved on, and for months experts have
been urging the government to reconsider the approach — warning that these
measures alone won’t prevent infections. One leading public health researcher,
speaking to the Daily Mail, went as far as to brand many of the rules as “well
meaning but pretty much useless.”
Last week we revealed how workplaces were ignoring Public
Health England guidance by relying on temperature checks — which had been found
to be inaccurate and ineffective at picking up COVID-19 cases.
Could a fixation with one-way systems and two-meter rules
also present a similar problem? Giving the illusion of safety, while
distracting us from the true risks?
Part of the problem lies in the fact that, initially, it was
believed COVID-19, like colds and flu, is mainly transmitted through coughs and
sneezes. When sprays of tiny moisture droplets carrying the coronavirus are
expelled this way, they can land on other people and potentially infect them.
But these droplets are also subject to the laws of gravity — they travel just a
meter or so before falling to the ground.
Mask-wearing is a vital measure to mitigate the risk of this
sort of transmission — they block droplets from being expelled from the mouth
and nose. This became particularly relevant when it emerged that large numbers
of people with COVID-19 get few, if any, symptoms but are still potentially
infectious.
But it has become increasingly clear that droplets are not
the only way the disease spreads. Infection also occurs from so-called airborne
exposure to the virus.
Microscopic viral particles can remain hanging in the air
for hours, like smoke, experts have warned. Outdoors, these particles are
quickly blown away.
But indoors, without adequate ventilation, this viral
“smoke” rapidly builds up.
Again, masks can mitigate this to a degree, soaking up some
of these particles. But they aren’t 100 percent effective, and this means that
simply being in the same room for any length of time with someone carrying
COVID-19 poses a risk, no matter how far apart you are.
Studies of super-spreader events — of which there have been
many — are proof of this.
In March last year, there were reports that 50 people who
attended a choir practice in the US state of Washington for an hour and a half
were subsequently diagnosed with the virus.
Two of them died.
And then there are the outbreaks in meat factories.
Researchers who studied a slaughterhouse in Germany, where about 1,500 workers
contracted the virus, suggested cold and stale air conditions allowed
coronavirus particles to travel more than 26 meters.
In December, an outbreak in Adelaide, Australia, was traced
to a security guard at a quarantine hotel. After examining CCTV footage, it was
concluded he caught the virus by standing outside the room of a
COVID-19-positive couple. Health chiefs said poor ventilation was to blame. The
list goes on and on.
In a study, researchers had a young woman who’d tested
positive for COVID-19, but had mild symptoms, drive a car that contained a
virus-detecting sensor. It was still picking up viral particles in the air two hours
after she had got out. This, perhaps, explains why during the first wave of the
pandemic, in the UK, men who worked as cab drivers were found to be most likely
to die from COVID-19.
In October the US Centers for Disease Control updated its
guidance on transmission, recognizing that airborne transmission can occur in
enclosed, poorly ventilated spaces.
A month later more than 200 scientists signed an open letter
urging all public health authorities to recognize the potential for the
airborne spread of COVID-19. They highlighted numerous studies that had proven
the virus could easily travel more than 9 meters.
Due to the tiny size of these particles, they settle in the
air at a height of about 1.5 meters, research suggests.
Last week, the UK government updated its “hands, face,
space” slogan to include “fresh air” — acknowledging that being outdoors
presents the lowest infection risk. But what about the air in offices, shops,
and restaurants?
Cath Noakes, a professor of environmental engineering for
buildings at Leeds University who campaigned for the slogan change, warns: “The
virus is carried in people’s breath. If you’re close to someone who’s infected,
you are at higher risk, so social distancing does matter. But it only deals
with part of the risk.
“If you are indoors, in a poorly ventilated space, viral
particles build up and we breathe them in.”
The health and safety executive says the law requires
employers and business owners to open windows or install mechanical ventilation
— fans and ducts that bring in fresh air from outside.
“Spaces that are most risky are those that have no
mechanical ventilation, or access to open windows and doors,” says Noakes.
Without good ventilation, those social-distancing stickers,
one-way systems and desk-dividing screens — “Ah, the magic screens,” Noakes
chuckles — are fairly futile.
Trish Greenhalgh, a University of Oxford public health
expert, was even more critical of many social-distancing measures.
She said: “Distancing round the sinks and urinals would only
work if the mode of transmission were limited to droplets. The virus is
airborne. We need to ventilate to reduce its transmission.”
Outdated COVID-19 safety measures could be putting us in
harm’s way.
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