With a whole host of safety regulations in place, flying is statistically the safest way to travel as you are least likely to die of a crash when compared to other modes of transportation. But since COVID-19 has spread across the world, often through international air travel, does embarking on an international flight post a significantly higher risk of COVID-19 infection than if you stayed in one place? Not necessarily.
Since reliable data is scarce, it is still too early to tell. At this point in time evidence says that it depends on where you’re flying to and from. The below is my opinion based on information I could gather online and personal experience of flying over 23,000km across three continents between February and August 2020, I am neither a statistician nor a scientist. All my flights were necessary from an immigration control perspective.
In the US, it depends on which airline you fly with
A recent article in August by New Scientist points out the ratio of positive tests to population per day is about 1:6,500. While the risk of infection in domestic US flights are indicated to be around 1:4,300 on 2-hour long flights with 3-a-side configuration, the risk could drop significantly to 1:7,700 if the middle seats were left empty, assuming that the aircraft are full in their respective configurations.
Currently, Delta, JetBlue, and Southwest have a policy of leaving the middle seats empty. It’s also important to keep in mind that US domestic passenger flight numbers are only around 30% of what they were in equivalent months in 2019 so it’s likely that the flights will not be completely full even if airlines do not leave the middle seats empty.
On US domestic flights of around 2 hours or less, it is best summarized as:
“These death-risk levels are considerably higher than those associated with plane crashes but comparable to those arising from two hours of everyday activities during the pandemic.”
Professor Arnold Barnett, Sloan School of Management, MIT
For international flights, it’s more complicated than that
Confirmed infection rates vary wildly from country to country, even if we only have developed economies in consideration that have the capacity and ability to perform massive accurate testing for COVID-19. The cumulative confirmed infection rate in South Korea is less than 4 in 10,000 while Germany (with a comparable population, climate, and economy) has a rate of about 29 in 10,000.
Some estimates put the risk of infection on an aircraft from the UK at just 2.5:10,000 considering that its infection rates were 10 times lower than that of the US. The Canadian transport minister also said that there was no indication of a COVID-19 transmission in commercial flight in Canada. It seems to me that flying internationally is not riskier than any other daily activity outside of the home.
Factors reducing transmission risk in international flights
If you need to fly internationally during a global pandemic, remember to fly direct if you can to reduce number of contacts with other travellers and to maintain preventative measures in airports before and after the flight. If someone infected flies on your flight and you sit at least 3 rows away on the aircraft, the risk of infection is less than 1%, but you could still get infected if you take your mask off and talk to them at the airport.
In the event that a connection is unavoidable, avoid bargain deals that require you to transit through third countries like the UAE or Qatar. Always connect in the same customs union of your departure or arrival country, if possible. On my flight from Geneva to Hong Kong I transited in Frankfurt (part of Schengen), and I transited through Vancouver on my flight from Hong Kong to Ottawa.
When I arrived in Hong Kong on my Lufthansa flight, I was allowed to quarantine at home after my COVID-19 test came back negative while travellers who transited through Doha were subject to additional scrutiny. Connecting in a third country increases exposure to other travellers from customs unions of much higher risk levels in developing economies, which in turn increases your risk of being infected.
Known knowns of international flights, unknown knowns of community transmission
Travel website trip.com has a handy page informing travellers of travel restrictions and quarantine requirements of different countries. Restrictions include quarantine ranging from 7 days in Singapore to 14 days in North America, requirement to have a negative test for COVID-19 in Cambodia, and contact tracing. All this is in addition to sterilization of airline cabin interiors after every flight and HEPA filters on that clean 99.97% of cabin air every few minutes.
Meanwhile, a study in Austria indicated with 95% certainty that approximately 55% of all cases in 6 countries in Europe are undetected. This could be due to lack of universal testing or asymptomatic cases, meaning that the number of confirmed cases could constitute to just 45% of the real infection rate. If we go back to our examples of South Korea and Germany, this could push the numbers up to 9 in 10,000 and 64 in 10,000 respectively, potentially making flying statistically safer than going to a crowded supermarket several times a week.
International flights between developed nations with proper contact tracing, quarantining, and testing after arrival eliminates the unknowns by testing everyone while it still remains very difficult to test everyone in any given city. Flying internationally during COVID-19 isn’t as scary as you think, but you should still avoid it if you can.
