Study Finds 16 Passengers On A Single Flight Caught Covid-19, What Does This Mean For Air Travel?

A new study identifies a flight in February on which spread of Covid-19 might might have occurred. It’s being used by airline unions to call for a ‘national mask policy’ on flights, even though all U.S. airlines already require masks, and it’s being used to attack President Trump over masks.

It’s an interesting and detailed look at a single flight on which 100 passengers originated in Wuhan, China. It’s also not the first flight where there were suspected cases of Covid-19 spread on a plane. A March 1 Vietnam Airlines flight from London Heathrow to Hanoi carried passengers who later tested positive for the virus.

Given the number of people in the world confirmed to have been infected by SARS-CoV-2, and the number of flights that have taken place throughout the pandemic I’d be surprised if there hasn’t been a single incident of spread on a plane somewhere during that time. What’s most striking is how few we’ve been able to find, not just in the U.S. but worldwide, regardless of what you think of variance in contact tracing capabilities in different locations. (A $295 million contact tracing contract in Texas has generated basically no actual work.)

In each of these instances of suspected inflight spread what you want to look for is whether it’s likely the people on the flight were infected elsewhere.

  • You may find that spread is among members of an immediate family, or among a group that was traveling together.

  • You may find that spread occurs in pockets of the aircraft that aren’t close to each other, a couple of passengers in one part of the cabin and a couple in another.

These things may suggest that it’s not a case of a person being infected, and people near that person catching the virus.

If you see clusters on a plane of unrelated people sitting in rows near each other, it may also be that they picked up the virus waiting in the gate area before the flight, or on the jetway (since nearby rows tend to be boarded together). The reason that matters is because knowing where during travel spread occurs leads to different policy responses.

  • Do we need to make sure passengers are better distanced in gate areas, perhaps gate areas better cleaned, or maybe that there’s more outside air on jet bridges?

  • Or is it really happening on a plane, so distancing does actually matter if virus spread is happening at scale?

Researchers studied a 4:30 p.m. Singapore Airlines Boeing 787 flight from Singapore to Hangzhou on January 24, 2020 which had 335 passengers on board along with 11 crew. 100 passengers “had visited Wuhan” – arriving in Singapore 5 days earlier – and containment procedures were in place on arrival, not least of which because “several passengers had already developed fever or upper respiratory infection symptoms” (suggesting that their exposure happened prior to the flight).

These passengers tested positive for SARS-CoV-2 the following morning, and ultimately 16 passengers from the flight would test positive (6 of whom were asymptomatic). The final two cases were identified on February 2, 9 days after the flight.

  • 15 of the 16 who tested positive originated in Wuhan.

  • 10 out of 16 passengers who tested positive were related to someone else who tested positive, or were part of a single tour group. Four passengers consisted of two couples, seated nowhere near other confirmed cases, suggesting they may have been exposed together outside of the flight. The other two cases weren’t seated within a row of anyone else who tested positive.

  • The closest person among the remaining passengers who contracted the virus was a 44 year old male two rows away and in a separate aisle from others who tested positive. He was one of the last two to test positive. It’s impossible to say where or when they contracted it, but they’re the only one on board who hadn’t traveled to Wuhan that tested positive.


    Credit: Travel Medicine and Infectious Disease, July-August 2020

If the passenger who hadn’t traveled to Wuhan did pick up the virus inflight, what’s remarkable is that with 15 people that had been in Wuhan in January ultimately testing positive for the virus only one other person on the aircraft got it. What’s remarkable is the lack of spread, rather than that there’s spread, considering the number of infected persons on board.

While the paper is being taken as proof of inflight spread the researchers actually conclude only that transmission of the virus “may have occurred during the flight” though it looks like “the majority of the cases..could not be attributed to transmission on the flight but were associated with exposure to the virus in Wuhan or to infected members in a single tour group.”

With less talking (fewer respiratory droplet emissions), HEPA air filtration, and a high rate of cabin air refresh many mainline passenger jets are safer from a virus spread perspective than dining inside a restaurant or doing any number of other activities that are permitted in many states. That is likely even more the case with mask enforcement becoming near-universal and much more common by commercial airlines.

Nonetheless it’s difficult to imagine any activity done at scale that won’t see some spread of the virus. Absent a ‘full Wuhan’ lockdown policy, passenger cabins are probably low on the list of concerns to address.

Dr. Eric Feigl-Ding attributes at least one case on the flight to lack of mask wearing and that’s an important takeaway, because if spread happened on board it may be that a properly worn quality mask would have prevented it.

That’s a separate matter from travel itself, whether someone with the virus might bring it with them to an area that currently has low infection and generate an outbreak at their destination. That’s why I’ve suggested that the ban on Europeans coming to the U.S. came too late (but no longer makes sense) and why I’ve been surprised to see relatively few limits on domestic travel. Much of the spread being experienced in the country today likely originates with people who had it in New York (and to a lesser extent on the West Coast) and traveled inland.

About Gary Leff

Gary Leff is one of the foremost experts in the field of miles, points, and frequent business travel - a topic he has covered since 2002. Co-founder of frequent flyer community InsideFlyer.com, emcee of the Freddie Awards, and named one of the "World's Top Travel Experts" by Conde' Nast Traveler (2010-Present) Gary has been a guest on most major news media, profiled in several top print publications, and published broadly on the topic of consumer loyalty. More About Gary »

More articles by Gary Leff »

Pingbacks

Comments

  1. Whatever the result or implications, I am sure we will now see a parade of the usual downers on these comments with “I don’t feel safe flying until there’s a vaccine”, “Wear masks, save lives”, “We need more testing”

    Etc, Etc, blah blah blah.

  2. @DB – I dunno, he knows a lot more about how disease spreads than I do, even if we sometimes disagree on the policy conclusions that flow from it. In any case there does seem to be some prophylactic benefit to masks, even less than the best masks.

  3. You don’t need this study to attack Trump on masks or his continuing failure to keep Americans safe from Covid-19. With respect, leave epidemiology to epidemiologists not travel bloggers.

  4. Interesting that no-one in F/J tested positive for it, which seems to support it was spread at the gate and/or among travel groups.

  5. @john – I’m writing about what the epidemiologists are saying, and they’re not the ones attacking the current administration in this case, politicians are using the study to do so (maybe you ought to be directing your admonition about who should be commenting on epidemiology to Democratic pols?)

  6. Given that the passengers seated in 11E/F and 12F departed from Wuhan and were seated in as close proximity to as many positive carriers as “passenger 16” as well as at least 2 dozen other passengers in proximity to positive carriers, this looks like one big red herring. Passenger 16 could have contracted it anywhere. Your chances of (or not) contracting it in-flight seems to be the same as an any enclosed close contact environment and therefore as with everything with this virus, do what you feel comfortable with at your own risk.

  7. This cannot be trusted and should not have been posted – it’s wrong on science and wrong on US Air carriers.. #SHAME

  8. I heard AA is in the process of getting federal approval to shrink wrap all passengers in cellophane before boarding the aircraft. AA will then be able to sell the middle seat without much public uproar. This would mean no food and beverage service for the immediate future. I still haven’t figured what this means for those that need to use the lavatory.

  9. Great article. It’s great to have actual, specific facts around which to discuss COVID, flying, masks etc. More articles like this please.

    And more comments like Vernon’s, which actually address the facts in the article.

  10. I read the study, and it doesn’t support these conclusions at all. It attributes a single case as “possibly” arising from the flight, and the attributes the rest of the cases to infection elsewhere.

    “One passenger without an epidemiological history of exposure before boarding developed COVID-19. During the flight, he was seated near four infected passengers from Wuhan for approximately an hour and did not wear his facemask correctly during the flight.”

    If this is the worse case scenario — a bunch of infected people from Wuhan at the height of the uncontrolled pandemic who get on a plane and surround and “possibly” infect a single person not wearing a mask — it would seem to be incredibly thin evidence to limit flying at this time. I would suggest that it provides evidence for the opposite conclusion . . . . flying is safe if any reasonable precautions are taken, and of which (preventing infected people from places with uncontrolled epidemic from boarding, wearing a mask, etc.) could have prevented even this single case of infection, if it did occur on this flight (which the paper can’t conclude even happened).

  11. The facts that new studies since then have found COVID in US and Europe well before February and the extremely variable incubation period make it doubtful that this passenger definitely got it on the plane.

  12. If mask wearing was taking place in January, no one would have gotten infected. Now with mask wearing, cleaning, limited contact and HEPA filters, the chances are low.

  13. @Gary, There are several places where it appears to me you go beyond reporting what epidemiologists are saying and draw your own conclusions or speculate about spread. My impression is you are making the case that the risks of air travel are not as great as people think.

    Even though well intended, meaningful discussion of issues related to Covid-19 and SARS-CoV-2 that remain unresolved by epidemiologists is beyond the effective scope of this blog or any other blog in the travel arena that I know of.

    When it comes to serious illness or death, when there is any doubt, erring on the side of caution is preferable to the opposite alternative.

  14. we cannot let a single person fall under covid, we must totally eliminate the risk or else we don’t open the economy. why rush to get back when gov is going to send us $40-$50k a year stay unemployed. the difference between covid & all other life incidents (winter flu, traffic, fire, drug, suicide..) is gov is not giving any money for them. at least stay this way till Nov, all bets are off after that.

  15. @John – my speculation – which I often flag as such – is based on prior reporting of other research papers.

    The risks of air travel appear to be clearly not as great as what many people think, based on this paper and other evidence presented so far. That doesn’t mean there’s no risk. But it’s often a place people are uniquely scared of, when it seems less risky than most other indoor activities.

    I agree that the elderly, especially elderly with comorbidities, should approach any activity right now with caution.

  16. Thanks for the article. Amazing that it’s likely only person (out of 346) contracted COVID from transit on an airplane. And he was unlucky enough to be surrounded on both sides by people likely already infected with COVID and himself not wearing his mask properly. It’s incredible that more people didn’t become infected.

  17. @Mak – that Atlantic piece from January seems to imply he was overly alarmist on Covid-19, I’m not sure history over the past several months hasn’t proven the overall thesis correct even if some of the particulars in a virus we were or still are learning a lot about quickly turned out to be off.

  18. So one plane 5 months ago might have contributed to the spread…and in China where the news is 100% trustworthy. How is a responsible organization of any type reporting this like it is news of some kind? This is just a story to continue to spread panic about the virus and further hurt economies, especially travel related businesses. This is rediculous.

  19. @mak – you failed to mention that he achieved a dual doctorate in epidemiology and doctorate in nutrition at age 23 from Harvard University.

  20. @Gary Leff I was taking issue with the headline, which I don’t think is supported by the article. “Study Finds 16 passengers on a single flight caught covid-19″ — that’s just not right.

    I’m not sure that the assistance of hindsight has made Feigl-Ding’s fearmongering correct, even if only by coincidence.

    “Ding claimed that the new virus was eight times as infectious as SARS.”

    “How bad is that reproductive R0 value? It is thermonuclear pandemic level bad—never seen an actual virality coefficient outside of Twitter in my entire career. I’m not exaggerating.”

    “The world is “faced with the most virulent virus epidemic the world has ever seen.”

    In reality, while Covid is quite bad, the above panic statements have been very far from true. Unlike Feigl-Ding’s predictions, it has turned out that — as John Ioannidis, Knut Wittkowski, and Richard Epstein suggested — many would have or develop immunity and would never get the disease, lowering the R0 as infection progressed. This is far from thermonuclear level as 40%+ of people who contract Covid are asymptomatic and never even know they have it, most of the rest of those infected will have only minor symptoms, and that the overwhelming majority of fatal cases involve elderly and infirm people with significant co-morbidities already near the end of their lives. In fact, the supposed cure to the Covid pandemic has been materially worse than the sickness, and we will be paying the price for many years in lost prosperity, happiness, education, peace, and even health. Covid has been bad, but the response by governments around the world have largely been a complete disaster.

  21. @Mak is absolutely right. The cost we have all paid to save (maybe a few hundred thousand) lives of already sick and old people is devastating not to hundreds of millions, but billions of people. This is what we get for living in an ‘everyone gets a trophy’ generation. When will individuals understand that they don’t really matter in a world population of billions. The fact that people make this abut democrats or republicans is so obtuse. Like Trump making a mask law has anything to do with this. How about people just being smart about it on their own regardless of who sits at a desk in Washington. Why aren’t we using this as an opportunity for population control, or as Darwin called it, survival of the fittest. We’re all fighting about masks and how far apart to sit on planes. How about this, if you’re afraid to fly, don’t. If you’re afraid to stay at a hotel, don’t. If you think a mask is going to save you, wear one. These lock-downs and impossible to enforce quarantines are such a waste. We are destroying everything for what?

  22. One problem is that there are no useful tracing mechanisms in the US. And since someone could be exposed to it but either not show symptoms for days, or be asymptomatic and never get tested you don’t know who could have had it or how many others it was passed on to.

    You can see that with the baseball team (Marlins). Some are positive, some are negative but how many of the negative tested players will eventually test positive? And if they all aren’t quarantined, then how many others will they spread it to.

    My GF and 4 members of her family tested positive in late June. Most had mild symptoms and she has been fine for weeks but still tested positive last week. She is unlikely to be contagious at this point but some companies require multiple negative tests before returning to work. I read that one nurse took 10 weeks to finally test negative twice in a row. Her hospital (like many others) have backed away from that policy.

  23. Many of the passengers who got it were clustered quite close to each other on plane. In rows 11-12 and then near the closest bathroom to those passengers. Could they have gotten it at the gate? Sure. But I would have suspected a more random splattering of cases

  24. When deplaning people are literally on top of each other, generally for several minutes. If I can smell someone’s perfume 3 rows away then the wonderful HEPA filtration system isn’t nearly good enough. When returning from Moscow on a 9 hour flight someone was coughing and hacking four rows over the entire flight. Sure enough, I got deathly ill.

  25. If CHINA had not lied to us and stopped flights in dec or jan we would not be having this conversation!! thanks again to CHINA for all of this….

  26. Kind of surprising how many similar case studies of viral spread fail to genotype the virus (sequencing the rna of the virus which can now be done very quickly at fairly low cost; see work of DeRisi et at at ucsf) found in infected persons. By genotyping , you can tell with fair deal of certainty who gave virus to whom due to relatively constant rate of mutation of the virus to avoid all waste in extra time/potentially unnecessary precautions due to assumptions of where/when the infections occur during travel.

Leave a Reply

Your email address will not be published.