Risk of contracting virus on airplanes - perspective
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Inhttps://www.nature.com/articles/d41586-020-00502-w
21 September — Business-class passenger spreads coronavirus on flight
Genetic evidence strongly suggests that at least one member of a married couple flying from the United States to Hong Kong infected two flight attendants during the trip.
Researchers led by Leo Poon at the University of Hong Kong and Deborah Watson-Jones at the London School of Hygiene & Tropical Medicine studied four people on the early-March flight (E. M. Choi et al. Emerg. Infect. Dis. https://doi.org/d9jn; 2020). Two were a husband and wife travelling in business class. The others were crew members: one in business class and one whose cabin assignment is unknown. The passengers had travelled in Canada and the United States before the flight and tested positive for the new coronavirus soon after arriving in Hong Kong. The flight attendants tested positive shortly thereafter.
The team found that the viral genomes of all four were identical and that their virus was a close genetic relative of some North American SARS-CoV-2 samples — but not of the SARS-CoV-2 prevalent in Hong Kong. This suggests that one or both of the passengers transmitted the virus to the crew members during the flight, the authors say. The authors add that no previous reports of in-flight spread have been supported by genetic evidence.
21 September — Business-class passenger spreads coronavirus on flight
Genetic evidence strongly suggests that at least one member of a married couple flying from the United States to Hong Kong infected two flight attendants during the trip.
Researchers led by Leo Poon at the University of Hong Kong and Deborah Watson-Jones at the London School of Hygiene & Tropical Medicine studied four people on the early-March flight (E. M. Choi et al. Emerg. Infect. Dis. https://doi.org/d9jn; 2020). Two were a husband and wife travelling in business class. The others were crew members: one in business class and one whose cabin assignment is unknown. The passengers had travelled in Canada and the United States before the flight and tested positive for the new coronavirus soon after arriving in Hong Kong. The flight attendants tested positive shortly thereafter.
The team found that the viral genomes of all four were identical and that their virus was a close genetic relative of some North American SARS-CoV-2 samples — but not of the SARS-CoV-2 prevalent in Hong Kong. This suggests that one or both of the passengers transmitted the virus to the crew members during the flight, the authors say. The authors add that no previous reports of in-flight spread have been supported by genetic evidence.
I'm 99.99...% sure that I had "it" back in December before it was fashionable, caught most likely on a flight from HKG to HND (6 hours or so iirc). I was in biz class. I could have caught it at the airport but I spent most of my time there practically alone in the Thai lounge.
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Does the timing of the positive tests prove that the passengers did not contract the virus from the cabin crew? Not sure it makes much difference although an infected crew member seems likely to spread the virus to more pax than vv.
While there is every reason to suspect that passengers/crew on a flight can catch the virus from others on board, it's pretty well impossible to prove based on on timings alone that a specific infection occurred on a particular flight.
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Indeed, but in this case the genetic evidence seems strong for transmission during the flight. My question was whether the timing evidence demonstrated the likely direction of transmission.
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I can only quote the referenced paper.
Given the case histories and sequencing results, the most likely sequence of events is that one or both of passengers A and B contracted SARS-CoV-2 in North America and transmitted the virus to flight attendants C and D during the flight. The only location where all 4 persons were in close proximity for an extended period was inside the airplane. Passengers and cabin crew do not generally go through the same check-in process at airports before boarding. Although we cannot completely rule out the possibility that patients C and D were infected before boarding, the unique virus sequence and 100% identity across the whole virus genome from the 4 patients makes this scenario highly unlikely. Patient D may have acquired infection from patient C, but because their test results were positive within 1 incubation period, it is more likely that patient D was infected by patient A or B. We therefore conclude that these 4 patients belong to the same in-flight transmission chain.
Our results strongly suggest in-flight transmission of SARS-CoV-2. No other COVID-19 cases associated with this flight have been identified. We were unable to quantify the virus attack rate on this flight because not all passengers were tested.
Given the case histories and sequencing results, the most likely sequence of events is that one or both of passengers A and B contracted SARS-CoV-2 in North America and transmitted the virus to flight attendants C and D during the flight. The only location where all 4 persons were in close proximity for an extended period was inside the airplane. Passengers and cabin crew do not generally go through the same check-in process at airports before boarding. Although we cannot completely rule out the possibility that patients C and D were infected before boarding, the unique virus sequence and 100% identity across the whole virus genome from the 4 patients makes this scenario highly unlikely. Patient D may have acquired infection from patient C, but because their test results were positive within 1 incubation period, it is more likely that patient D was infected by patient A or B. We therefore conclude that these 4 patients belong to the same in-flight transmission chain.
Our results strongly suggest in-flight transmission of SARS-CoV-2. No other COVID-19 cases associated with this flight have been identified. We were unable to quantify the virus attack rate on this flight because not all passengers were tested.
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Crew are being quarantined some places, not optionally. Pilots may get away with it (not as dumb as it sounds - being in prolonged contact with anyone not also on flight deck is/should-be unlikely). See e.g.:
https://liveandletsfly.com/hong-kong...ine-detention/
https://viewfromthewing.com/british-...nt-quarantine/
https://liveandletsfly.com/hong-kong...ine-detention/
https://viewfromthewing.com/british-...nt-quarantine/
The other issue with enforced quarantine for everyone is that accommodation is limited (some Pacific countries with few or no cases are considering quarantining all arrivals). Several hundred people arrive on each plane so the beds soon fill and remain full for two weeks until the next group of people fill the beds.Meanwhile no further arrivals are possible.
Obviously this won't work, so can testing and exemption be used instead?
Obviously this won't work, so can testing and exemption be used instead?
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Peter H
The great thing about these last two reports is that they are by professionals, with no axe to grind, with significant expertise in the field.
No matter what evidence they have, no matter how irrefutable the data is . . . there will always be a knuckle dragging neanderthal minority who just don't believe them . . . loudly teling everybody who will listen.
Policy is not set by the knuckle draggers.
The evidence will inevitably keep mounting.
The great thing about these last two reports is that they are by professionals, with no axe to grind, with significant expertise in the field.
No matter what evidence they have, no matter how irrefutable the data is . . . there will always be a knuckle dragging neanderthal minority who just don't believe them . . . loudly teling everybody who will listen.
Policy is not set by the knuckle draggers.
The evidence will inevitably keep mounting.
Andrewgr2
According to the paper, the two passengers were symptomatic on the day that the flight arrived in Hong Kong which makes it extremely unlikely that they were infected on the flight. One of the cabin crew is described as developing symptoms over a week after the flight arrived making it much more likely that the transmission was in that direction. The authors allow for the (remote) possibility that the infection did not occur on the flight, but not that the cabin crew infected the passengers.
According to the paper, the two passengers were symptomatic on the day that the flight arrived in Hong Kong which makes it extremely unlikely that they were infected on the flight. One of the cabin crew is described as developing symptoms over a week after the flight arrived making it much more likely that the transmission was in that direction. The authors allow for the (remote) possibility that the infection did not occur on the flight, but not that the cabin crew infected the passengers.
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Evidence based on timing? Not really solid. On genomic tracing? Yes, solid.
https://www.abc.net.au/news/2020-09-30/covid19-ruby-princess-passengers-infected-qantas-coronavirus/12718748
https://wwwnc.cdc.gov/eid/article/26/12/20-3910_article
https://www.abc.net.au/news/2020-09-30/covid19-ruby-princess-passengers-infected-qantas-coronavirus/12718748
https://wwwnc.cdc.gov/eid/article/26/12/20-3910_article
An ongoing 'Survey Monkey' survey of airline crew members accessible through the GCAQE 'Cabin Air Quality' facebook page is showing about 25% of crews reporting COVID-19 typical symptoms. Yes, many of those flew before face masks became mandatory but it indicates that HEPA filters will not protect you from close proximity with an infected person.
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But did they get it on board, as opposed to the briefing room, the security queue or the crew bus? Or, if it's a company doing layovers, from socialising with other crew members? Thankfully, I haven't seen a COVID-19 outbreak in an airline - but lots of other cases of contagious stuff spreading like wildfire among an entire base. Especially all the flu-like stuff in the winter.
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what was before
Hi, it´s about the 2 flight attendants and the 2 passengers.
Yes, they were on the same flight - I´d say they started at the same airport, and all 4 were in the same city before the flight.
How about the theory that all 4 got the virus in the north american city where the flight started ?
Or....were the flight attendants confined to their hotel-room during layover, China-style , and thus unable to get the virus before the flight ?
Just my 2 bits....
Yes, they were on the same flight - I´d say they started at the same airport, and all 4 were in the same city before the flight.
How about the theory that all 4 got the virus in the north american city where the flight started ?
Or....were the flight attendants confined to their hotel-room during layover, China-style , and thus unable to get the virus before the flight ?
Just my 2 bits....
Coronavirus exposure risk on airplanes very low, U.S. defense study finds
(Reuters) - The risk of exposure to the coronavirus on flights is very low, a U.S. Department of Defense study released on Thursday found, a positive sign for the airline industry as it tries to rebound from the pandemic’s crushing effect on travel.
The testing assumed only one infected person on the plane and did not simulate the effects of passenger movement around the cabin.
The study, conducted aboard United Airlines Boeing 777 and 767 aircraft, showed that masks helped minimize exposure to infection when someone coughed, even in neighboring seats.
About 99.99% of particles were filtered out of the cabin within 6 minutes due to fast air circulation, downward air ventilation and the filtration systems on the aircraft.
It estimated that to receive an infectious dose, a passenger would need to fly 54 hours on a plane with an infectious person.
United, which also provided pilots for the test, took pains to present the results in its favor.
“These results ... mean your chances of COVID exposure on a United aircraft are nearly non-existent, even if your flight is full,” said United Airlines Chief Customer Officer Toby Enqvist.
The study was led and funded by Transportation Command, which operates Patriot Express flights that use commercial planes like United’s for members of the military and their families.
The research over six months involved 300 tests during 38 hours of flight time and 45 hours of ground testing. It was done by releasing particles the same size as the novel coronavirus across the entire cabin by section, each of which had 42 sensors representing other passengers who could potentially come in contact with the particles.
Each test released 180 million particles – the number of particles that would be produced by thousands of coughs.
Study participants included the Defense Advanced Research Projects Agency (DARPA) and Boeing Co, among others.
Last week, plane manufacturers Boeing, Airbus SE and Embraer SA released a joint publication showing that cabin air filters limit the spread of viruses on their aircraft.
Their conclusions were based on computational fluid dynamics research that simulated how particles move around the cabin.
The International Air Transport Association (IATA) said it has identified only 44 flight-related COVID-19 cases since the beginning of 2020 versus some 1.2 billion passengers who have traveled during that time.
While “nothing is completely risk-free,” the published cases of potential inflight COVID-19 transmission show that “the risk of contracting the virus on board appears to be in the same category as being struck by lightning,” IATA Director General Alexandre de Juniac said.
The testing assumed only one infected person on the plane and did not simulate the effects of passenger movement around the cabin.
The study, conducted aboard United Airlines Boeing 777 and 767 aircraft, showed that masks helped minimize exposure to infection when someone coughed, even in neighboring seats.
About 99.99% of particles were filtered out of the cabin within 6 minutes due to fast air circulation, downward air ventilation and the filtration systems on the aircraft.
It estimated that to receive an infectious dose, a passenger would need to fly 54 hours on a plane with an infectious person.
United, which also provided pilots for the test, took pains to present the results in its favor.
“These results ... mean your chances of COVID exposure on a United aircraft are nearly non-existent, even if your flight is full,” said United Airlines Chief Customer Officer Toby Enqvist.
The study was led and funded by Transportation Command, which operates Patriot Express flights that use commercial planes like United’s for members of the military and their families.
The research over six months involved 300 tests during 38 hours of flight time and 45 hours of ground testing. It was done by releasing particles the same size as the novel coronavirus across the entire cabin by section, each of which had 42 sensors representing other passengers who could potentially come in contact with the particles.
Each test released 180 million particles – the number of particles that would be produced by thousands of coughs.
Study participants included the Defense Advanced Research Projects Agency (DARPA) and Boeing Co, among others.
Last week, plane manufacturers Boeing, Airbus SE and Embraer SA released a joint publication showing that cabin air filters limit the spread of viruses on their aircraft.
Their conclusions were based on computational fluid dynamics research that simulated how particles move around the cabin.
The International Air Transport Association (IATA) said it has identified only 44 flight-related COVID-19 cases since the beginning of 2020 versus some 1.2 billion passengers who have traveled during that time.
While “nothing is completely risk-free,” the published cases of potential inflight COVID-19 transmission show that “the risk of contracting the virus on board appears to be in the same category as being struck by lightning,” IATA Director General Alexandre de Juniac said.
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The testing assumed only one infected person on the plane and did not simulate the effects of passenger movement around the cabin.
I find the report encouraging in some ways - but, until there is sufficient compliance with the new rules, I'm still not getting on any public transport (aircraft included).
Just my POV.
It estimated that to receive an infectious dose, a passenger would need to fly 54 hours on a plane with an infectious person.
The International Air Transport Association (IATA) said it has identified only 44 flight-related COVID-19 cases since the beginning of 2020
The International Air Transport Association (IATA) said it has identified only 44 flight-related COVID-19 cases since the beginning of 2020
Is he/she seriously suggesting that those 44 unfortunate individuals took 54-hour flights?
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If one passenger needs to be on a flight, for 54 hours, with 1 infected person to catch Covid then ...
If there are 108 passengers on a half hour flight, with 1 infected person, then, on average, 1 passenger will be infected
Uses the same numbers!!!
As someone said: "There's lies, damn lies and then there's statistics" - you can make them say whatever you want.
If there are 108 passengers on a half hour flight, with 1 infected person, then, on average, 1 passenger will be infected
Uses the same numbers!!!
As someone said: "There's lies, damn lies and then there's statistics" - you can make them say whatever you want.
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Sloppy math behind the presentation too apparently. Latest seems to be that one of the authors of the original research objected to the way it's been used/presented, declined to take part in the presentation and is now publicly stating that the industry's risk analysis is "bad math". https://uk.reuters.com/article/healt...-idUSKBN27411O