The chance of catching Covid-19 on a flight is so small, you are probably more likely to pick the winning numbers in Australia’s Saturday Lotto, according to latest studies – with new tests by the United States Transportation Command (US Transcom) confirming the low risk of Covid-19 transmission aboard an aircraft.
The US Transcom test found the that the ventilation systems on two Boeing aircraft types in common use removed particulate matter five to six times faster “than the recommended design specifications for modern hospital operating or patient isolation rooms”. Airbus testing in Europe indicates similar.
The US Transcom testing was conducted in partnership with Boeing and United Airlines, along with the US Defence Advanced Research Projects Agency (DARPA), Zeteo Tech, S3i and the University of Nebraska’s National Strategic Research Institute.
The encouraging results arrived, coincidentally, as Australasia’s one-way “travel bubble” began, in which New Zealanders are allowed to fly to New South Wales, Canberra and the Northern Territory (but not to Victoria!)
It has long been known that the chance of catching Covid-19 in flight is low, but it was not generally appreciated how low.
Last week, The International Air Transport Association (IATA) confirmed that since the start of 2020, 44 cases of Covid-19 had been reported in which transmission was thought to have been associated with a flight journey, out of 1.2 billion passenger journeys in 2020.
“With only 44 identified potential cases of flight-related transmission among 1.2 billion travellers, that’s one case for every 27 million travellers,” IATA’s Medical Advisor, Dr David Powell, commented.
For comparison, Australia’s regular Saturday Lotto gives a one in 8,145,060 chance of winning the big one – which is over three times more likely than one in 27 million.
Dr Powell conceded, however, that “we recognize that this [one in 27 million] may be an underestimate – but even if 90% of the cases were un-reported, it would be one case for every 2.7 million travellers. We think these figures are extremely reassuring. Furthermore, the vast majority of published cases occurred before the wearing of face coverings inflight became widespread.”
Facemasks lower the chance of contagion still further.
The US Transcom tests involved more than 300 aerosol releases, simulating a passenger infected with Covid-19, performed over eight days using United Airlines Boeing 767-300 and 777-200 twin-aisle aircraft.
Testing showed that the aerosol was “rapidly diluted by the high air exchange rates” of a typical aircraft cabin. Aerosol particles remained detectable for a period of less than six minutes on average. Both aircraft models tested removed particulate matter 15 times faster than a typical home ventilation system and 5-6 times faster “than the recommended design specifications for modern hospital operating or patient isolation rooms.”
Testing was done with and without a mask for the simulated infected passenger, showing the overall exposure risk from aerosolized pathogens, like coronavirus, to be very low.
Finally, those Saturday Lotto odds, one in 8,145,060. Dr Stephen Woodcock, Senior Lecturer in the School of Mathematical and Physical Sciences at the University of Technology, Sydney, has given a graphic description of what that represents.
Speaking to SBS World News, Dr Woodcook said those odds were “a little bit less likely than getting 27 people each to flip a fair coin and seeing all 27 coins land the same way”.
Written by Peter Needham
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