IATA,
Aircraft Manufacturers Provide Proof Of Low Inflight Virus Transmission Risk
Karen Walker October 08, 2020
Briefing media Oct. 8,
IATA medical advisor David Powell said about 44 people are thought to have
caught the virus during a flight. That is among the 1.2 billion people who have
flown so far this year, making the risk of transmission about one in 27.3
million. Even if some 90% of cases were not reported and the risk were 10 times
higher, it would mean the likelihood of catching the virus that causes COVID-19
on a flight would be one in 2.73 million, making it “an uncommon event,” Powell
said.
He compared it to the
probability of being struck by lightning, which he believed was between one in
500,000 and one in 1.2 million, making it a far higher risk.
Until a COVID-19
vaccine becomes available and virus testing is widely available, affordable and
rapid, the air transport industry is struggling to convince people that it is
safe to fly, although some progress appears to have been made in communicating
the multi-layers of measures that are in place and why they work. Powell said
that in a recent survey of people who had flown, 86% said they felt safe. But
60% said they felt cabin air was dangerous and the biggest single fear was of
catching the virus from a passenger sitting next to them. The other challenge
is convincing all those people who are not flying that it is safe to do so;
IATA August travel data showed that passenger numbers worldwide were still down
by 75% compared with a year ago.
Of the 44 known inflight transmission
cases, most occurred early in the year before masks were widely worn. Most
airlines now mandate masks for passengers and crews. Most of the cases involved
just one or two transmission on a flight. There were two exceptions, both
happening in March: a London-Hanoi flight in which 15 cases were confirmed and
a Sydney-Perth flight in which there were 11 cases. On the London-Hanoi flight,
12 of the infected passengers were in business class, two were in the economy
cabin and one cabin crewmember was affected, Powell said.
In the same briefing,
representatives of Airbus, Boeing and Embraer shared information on extensive
research they have conducted independently to understand the effectiveness of
onboard protections such as the cabin HEPA air filter system, top-to-bottom air
flows, the natural barriers formed by seatbacks, and mask wearing. All have
conducted 3D computational fluid dynamic models that have provided insight into
what happens to cough droplets in a cabin. The downward flow of air that comes
from the cabin ceiling and is completely refreshed every two to three minutes
pushes larger droplets to the floor and washes them out. Smaller aerosol
droplets, which can reach further, are also massively dissipated by the air
system.
Bruno Fargeon, leader
of Airbus Engineering’s Airbus Keep Trust in Air Travel initiative, said models
show a single cough by one passenger could create some 10,000 such droplets,
but a maximum of just five droplets might reach a passenger seated next to the
cougher. The same models also looked at what happens when a person coughs on
the ground but is socially distanced by 1.8 m (6 ft.) from other people. Models
found the likely maximum number of droplets that might reach a person 1.8 m
away was 10.
“So being on an
aircraft is safer than being six feet away on the ground,” Powell said. The
biggest difference is the effect cabin air and filters have on droplets.
Dan Freeman,
engineering director at Boeing’s Confident Travel Initiative, said the company
had done “vast amounts of research” and modeling and live testing on
narrowbodies and widebodies, taking worst-case scenarios with masked and
unmasked passengers. Even in worst-case scenarios, the research indicates that
being on an aircraft is equivalent to being 7 ft. or more away from other
people in an indoor ground environment, he said. Boeing models were done based
on full aircraft with every seat occupied.
Luis Carlos Affonso,
Embraer SVP engineering, technology and strategy, noted that their modeling
based on seven rows of seating did show that mask-wearing further reduced the
risk of droplets being dispersed, with the risk being six times higher if masks
are not worn.
“Masks should be
worn,” Fargeon agreed.
“We are not saying
there is no risk; it’s about relative risk to all the other things people do
and it’s important for people to understand that risk in air travel is very
low,” Freeman said.
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