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Flight risk - odds of picking up Covid on plane are low

Faye Flam


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Cabin pressure: Airlines have introduced new safety measure

Cabin pressure: Airlines have introduced new safety measure

Bloomberg

Cabin pressure: Airlines have introduced new safety measure

If you do decide to fly, the odds that you will pick up Covid-19 are low, according to one expert analysis. Despite the known dangers of crowded, enclosed spaces, planes have not been the sites of so-called superspreading events, at least so far.

That's not to say flying is perfectly safe - safety is relative and subjective. But as restrictions continue to change, the only way to move forward through this long pandemic is to start thinking in terms of risk-benefit ratios. Very little is without risk, but perhaps some risks - such as flying - are small enough to warrant taking.

Arnold Barnett, a professor of management science at the Massachusetts Institute of Technology (MIT), has been trying to quantify the odds of catching Covid-19 from flying. He's factored in a bunch of variables, including the odds of being seated near someone in the infectious stage of the disease, and the odds that the protection of masks - now required on most flights - will fail. He has accounted for the way air is constantly renewed in airplane cabins, which experts say makes it very unlikely you'll contract the disease from people who aren't in your immediate vicinity.

What Prof Barnett came up with was that we have about a one-in-4,300 chance of getting Covid-19 on a full 2-hour flight - that is, about one in every 4,300 passengers will pick up the virus, on average.

The odds of getting the virus are about half that, one in 7,700, if airlines leave the middle seat empty. He's posted his results as a not-yet-peer-reviewed preprint.

The odds of dying of a case contracted in flight, he found, are even lower again - between one in 400,000 and one in 600,000 - depending on your age and other risk factors. To put that in perspective, those odds are comparable to the average risk of getting a fatal case in a typical two hours on the ground.

The numbers all sound low enough, though Prof Barnett says they are still high compared to the one in 34 million odds your flight will end in a deadly crash. He told me he wouldn't fly right now because his age, 72, puts him at higher risk than the average American, and he says you have to consider the risk of adding to the problem by getting the virus and unknowingly passing it on to others.

Other experts have been mixed on whether they, personally, would fly. The Boston Globe recently reported that of 15 epidemiologists and infectious disease experts surveyed, 13 said they would not fly at this time. However, it wasn't clear whether they had any reason to get on a plane.

University of Massachusetts biology professor Erin Bromage says he is flying every week, as he advises federal, state and district courts on how to reopen while minimising risks. Whereas many experts are taking a zero-tolerance-for-risk approach, he's trying to find a middle ground and helping others do it in a rational way.

Prof Bromage says that the air exchange system in planes is better than in hospitals but agrees with MIT's Prof Barnett that it's possible to transmit the disease to or from your close neighbours.

He and Barnett both suggested that customers should, if possible, choose an airline that promises to keep the middle seat open. That cuts way back on the odds of getting or giving the virus.

Real-world data bodes well for flying, too. Australia has been using contact tracing to investigate Covid transmission on hundreds of flights, and has found that while infected people got on planes, nobody got infected on a plane. Worldwide, there have been a couple of individual transmissions possibly linked to flights, but no superspreading-type events.

Assuming we'll be living with this disease for months to come, we will need ways to separate low-risk activities from high-risk ones. Keeping informed of relative risks can help us do that. By worrying less about the relatively safer part of a trip - the actual flight - we can pay more attention to the potentially riskier parts, such as crowds and tightly packed lines at the airport.

What happens at your destination matters too. Traveling around and new contacts can increase the risk of spread.

In the old normal, Bromage would wrap up his advisory duties and have dinner with the people he's working with. Now, he just goes back to his hotel room. "It's quite lonely," he says. Like so much this year, it's a compromise.

Bloomberg