29 August 2020 | New Scientist | 11SITTING in a confined space for
hours with hundreds of strangers
sounds risky during a pandemic.
But while hard evidence is scarce,
it appears the risk of being
infected with the coronavirus
during a flight is relatively low.
“Overall, planes are probably
safer than poorly ventilated pubs,
where similar densities of people
do not wear masks and talk a lot
and loudly,” says Julian Tang at the
University of Leicester in the UK.
If you use public transport, the
risk depends firstly on the odds of
an infected person being on the
same bus, train or plane, and then
the odds of them infecting you.
Travelling in South Korea,
where just 1 in about 225,
people test positive every day, is
inherently safer than travelling
in the US, where 1 in 6500 people
test positive every day. In the UK,
it is 1 in 60,000 people.
If you do sit on a plane near
someone who is infected, how
likely are you to catch the virus?
We don’t know for sure as there
is little to go on, but some case
studies offer clues.
One describes a 5-hour flight
from Singapore to China, where
11 of the 325 people on board were
infected by one man. Passengers
were screened before boarding,
but the man developed a fever
during the flight and wasn’t
wearing a mask.
However, when an infected
couple flew from China to Canada
on 22 January, none of the 350
passengers on the 15-hour flight
were infected. Masks were worn.In a document on the evidence
for in-flight transmission, the
International Air Transport
Association (IATA), an industry
body, says that when four airlines
followed up with 1100 passengers
confirmed to be infected after
flying, just one may have been
infected by another passenger. It
isn’t clear how rigorous the finding
is, as no details were published
and the IATA didn’t respond to
queries from New Scientist.
There are reasons to think the
risks are low. Many airports check
people’s temperatures before theyboard, and airlines now disinfect
planes between flights and require
passengers to wear masks. The air
on planes is also replaced every
3 to 5 minutes, and the air that is
recirculated goes through HEPA
filters that should remove most
droplets containing viruses.
“The ventilation systems
on planes are very effective in
reducing the concentration of
any airborne pathogen exhaled by
passengers,” says Tang. The main
risk may be face-to-face talking
where air can be swapped before
being pulled away, he says.
In the US, the risk of infection
is about 1 in 4000 if a flight is full,
estimates Arnold Barnett at the
Massachusetts Institute of
Technology. If the middle seats
are left empty, the risk falls to 1 in- For the UK, the equivalent
risks are about 10 times lower, says
Barnett. That is, there is just a 1 in
40,000 chance of infection. These
are just rough estimates, however.
It isn’t clear how travelling on
trains or buses compares as their
ventilation systems vary. For
instance, the air on Eurostar trains
is replaced every 15 minutes. ❚
“ For the majority of people
with lung disease, wearing
a mask is a mild irritation
they can put up with”Air travel
Michael Le Page
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Why some people
cannot wear a
face covering
DO YOU get angry when you see
someone without a face covering?
They might have a good reason to
avoid one, even if it isn’t obvious.
Despite claims to the contrary,
face coverings don’t reduce the
amount of oxygen in the blood or
raise the level of carbon dioxide.
So people with lung conditions such
as asthma shouldn’t assume they
don’t need to wear one. “For the
vast majority of people with lung
disease, wearing a mask is fine.
It’s a mild irritation that they can
put up with,” says Nick Hopkinson
at the British Lung Foundation.
The exceptions are some people
who experience occasional
breathlessness due to conditions
such as emphysema and pulmonary
fibrosis. This can be due to
genuinely low blood oxygen, but
the conditions also make the lungs
stiffer, requiring the chest muscles
to work harder to pull in air. That
sends a misleading signal to the
brain that oxygen is in short supply,
which creates the feeling of being
short of breath, even if you aren’t.Face coverings can also trigger
anxiety and panic attacks in those
who are vulnerable, says UK mental
health charity Mind. People with
autism may have issues if they
experience heightened touch
or smell – so that a mask feels
smothering – or if they struggle
with the change to their routine.
Individuals with learning disabilities
may need to see their carer’s face for
reassurance and to communicate.In the UK, people are legally
exempt from wearing a face
covering if they are unable to use
one because of disability or if it
causes them severe distress. This
is subjective, so we should accept
the choice of individuals going
unmasked, says Tim Nicholls at
the UK’s National Autistic Society.
Those exempt can wear a
badge explaining their medical
reasons if they wish, but they
aren’t obliged to do so. “We have
to encourage people to wear a mask
if they can, but be understanding
if they can’t,” says Nicholls. ❚
Clare WilsonHow likely are you to catch
the coronavirus on a plane?
Face coverings and filtered
air could help minimise risk
of catching the coronavirusCoronavirus Essential Guide
All you need to know about coronavirus and covid-
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