Aircrafts are hotbeds of coronavirus transmission


Vijaya Laxmi Tripura

Airline companies clearly have an interest in selling more tickets. But should we buy their confidence?

According to the airline industry, it is safe to fly during the coronavirus pandemic. Here we need to remember, at the beginning of the pandemic, people who were infected with the virus boarded planes and rapidly seeded outbreaks all over the world.

But whether planes themselves are a dangerous place to become infected, and infect others, has been more of an open question. The truth is we don’t really know the answer yet. There are few high-quality studies on transmission on airplanes, and they all come with important caveats and uncertainties.

United Airlines boasts that the “risk of exposure to Covid-19 is almost non-existent on our flights.” Southwest Airlines has opened up middle seats for passengers, saying the odds of catching the coronavirus on a plane are “similar to the odds of being struck by lightning”.

Flying is not the most dangerous activity during the pandemic. It’s safer than, say, going to a crowded bar for drinks. But safer does not necessarily mean safe. There have been credible instances of transmission on planes, particularly on longer flights and earlier on in the pandemic (when the current guidelines for masking and other risk-reducing actions weren’t in place).

There are many gray areas — situations that arise in an airport and on a plane — that probably increase the chance of virus spread but aren’t well understood. For example, while scientists have looked at the risk of viral transmission in flight, they haven’t studied the transmission dangers posed by crowding during boarding or deplaning.

Flying may be a relatively low risk, but we must ask ourselves: Should we really be traveling in the first place? Getting on a plane might not even be the most dangerous part about travel — it could be the new exposure potential when you get to your destination.

Even though there isn’t one simple answer here, there are many, many ways both passengers and airlines can reduce risk.

Let’s dive in.

“How safe is air travel during the Covid-19 pandemic?” sounds like a simple question, but it’s deceptively hard to answer scientifically.

While Saskia Popescu, an infectious disease epidemiologist and assistant professor with George Mason University, commenting on the risk of coronavirus infection inside aircrafts said, “Overall, the risk of getting the virus on a plane is probably low, he noted, lower than going to a crowded bar or restaurant. But it’s not zero. What’s more. Travel is a process that is more than just the flight itself. Passengers need to weigh their tolerance of risk in this context. You may wind up in a line for boarding or the bathroom, where it’s harder to distance. When you’re traveling, I think you’re more at the hands of those around you in terms of how safe are they being”, Harvard report authors said, when more than 60 percent of seats on a plane are occupied, it is no longer possible to rely on physical distancing alone to mitigate the risk of virus transmission.

The flight described in the paper was a virtual hotbed of Covid-19: An astonishing 27 passengers had the virus upon arrival in Hong Kong from Dubai, meaning they were probably already infectious when they got on the plane. The researchers determined that they likely passed the virus on to two other people (both people were negative upon landing but tested positive by day 14). Notably, this was a flight where mask-wearing was mandatory, which may explain why the 27 index cases only generated an additional two cases.

The final example was essentially a slightly pared-down real-world version of the unethical experiment described earlier. Since April in Hong Kong, air travel passengers are required to submit to PCR testing upon landing and then quarantine for 14 days. The information on cases can tell us how many people on a flight are positive when they arrive at a destination, and how many go on to develop Covid-19 — suggesting they probably picked it up in the air.

According to another experts, the absence of evidence is not evidence of absence.” Since the burden of proving a Covid-19 case was generated in the air — and not through contact just before getting on the plane or just after — is really high, and not all passengers are followed up with, there’s probably a lot we’re missing.

So, what does this mean for the people who want to go home for the holidays or visit loved ones across the country? There are a few things we can take away from the opinion of experts.

Wearing of masks

Mask-wearing probably reduces your risk of catching the virus. Three of the mass transmission events — where more than one person got infected — Freedman’s study uncovered happened on flights early in the pandemic, when masking wasn’t mandatory. In contrast, in the flight from Dubai to Hong Kong, which carried 27 passengers who were coronavirus positive, there was universal masking in place and only two people got infected. (One of them was seated in a row with five people who tested positive for the virus on arrival.)

The circumstantial evidence is extremely strong that these [mass transmission] incidences we know about really stopped happening after the airlines started implementing some form of masking.

Wearing glasses or a face shield to cover your eyes too is probably even more protective (though face shields are not a substitute for masks).


Proximity matters. In all four real-world examples mentioned above, most of the cases were clustered near the person who was sick — and a minority happened more than three rows away from an index case.

People’s behavior

You’re subjected to other people’s behaviors on a flight in a way you can’t escape. Even with universal mask-wearing, people might remove their mask to eat or talk. Or they might not wear their mask properly. And flying is different from other activities we do that involve some coronavirus risk: If someone started coughing in a meeting or restaurant, you could simply walk away, but the same isn’t true for an airplane. People “don’t want to take a chance on being a prisoner in a circumstance they can’t control.

We need to know, given all the flying that’s happened during the pandemic and these relatively few well-documented examples of virus spread, the airline industry has been arguing that this means there’s a “low incidence of inflight COVID-19 transmission.

The good news

We know, the coronavirus pandemic, which initially appeared in China last December, has spread across the world and infected millions of people. Since then, the entire world has been witnessing terrible days as normalcy of lives were severely affected by social-distancing and fear of getting transmitted. Business sectors are worst affected with tremendous decrease in turnover, pushing hundreds of thousands of people towards unemployment. The global outbreak affected several sectors deeply, particularly aviation, tourism, travel, and manufacturing. Although several experts had predicted a sudden disappear of this pandemic and some had even expected a world free from coronavirus by June 2020, the harsh reality is – we already are witnessing a second wave and few experts are now prediction a much stronger shape of the pandemic during the winter. But of course, there is good news. According to media reports, coronavirus vaccine is all set to be available from December this year, which would liberate the global populace from the “imprisonment” of this pandemic.

Vijaya Laxmi Tripura is a research-scholar, senior journalist and Special Correspondent of Blitz


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