COVID-19 and flying – a medical expert’s view
As air travel is gradually starting to recover, many travellers are concerned about getting infected with novel coronavirus (SARS-CoV-2) when they travel. We sat down with Kimmo Ketola, Finnair’s Medical Director to talk about COVID-19 and flying.
Exactly how safe or un-safe from COVID-19 (the disease caused by SARS-CoV-2) are we, when flying?
“According to medical evidence so far, a passenger’s risk of in-flight transmission of SARS-CoV-2 is likely to be low or extremely low. The reasons for the apparently low rate of in-flight transmission are not known yet but could encompass a combination of the lack of face-to-face contact, and the physical barriers provided by seat backs, along with the characteristics of cabin air flow.
In commercial aircraft the cabin air is replaced on average every 3 minutes. Air circulation patterns aboard standard commercial aircraft are side-to-side with air entering the cabin from overhead, circulating across the aircraft and exiting near the floor. There is little longitudinal (front-to-back) airflow. The cabin air is a mix of recirculated and fresh outside air. The outside air is assumed to be sterile at typical cruising altitudes. All air passes through high efficiency particulate air (HEPA) filters that filter >99,97% of particles in the air, including bacteria and virus. The resulting air quality has been shown to meet the same standards as hospital operating theatres.”
Are there known cases of aircraft transmission of SARS-CoV-2 in-flight?
“Looking at what has been published on this topic in medical publications, there is only one paper that suggests a probable aircraft transmission of SARS-CoV-2 in-flight1.
One paper from Canada reports careful follow up of a long-haul flight on which a passenger was later confirmed to have been unwell at the time, but no secondary cases resulted1. In another yet unpublished report, a flight from USA to China with 11 people subsequently confirmed to be symptomatic at the time, similarly had, at the time of writing, generated no secondary confirmed cases from around 300 passengers tested2.
An inquiry to 70 airlines (representing half of global passenger traffic) failed to identify any cases of suspected passenger-to-passenger transmission3.
Naturally research continues on this topic, but looking at the evidence so far, the risk of transmission in an aircraft seems to be very low.”
How do the masks prevent transmission?
“Droplet transmission seems to be the major mode of contracting SARS-CoV-2 with possibility of transmission by contacts with surfaces. Generally, droplets are propelled short distances (<1 m) when an infected person sneezes, coughs or talks. A person with any respiratory symptoms will be denied boarding on Finnair flights.
In line with EASA’s recommendations, Finnair requires that passengers wear masks during the flight to tackle the risk of asymptomatic carriers transmitting the virus. By wearing a mask, we all protect each other. “
What about the surfaces in the aircraft, should we be concerned about transmission via surface contacts?
“Concern of transmission via surface contacts has been heightened by research indicating potential SARS-CoV-2 survival on a range of surfaces for a few days.
Nevertheless, cleaning with normal agents such as alcohol >70 % is very effective at destroying the virus on such surfaces. Many airlines have increased the frequency and extent of their routine cleaning, and also the European Aviation Safety Authority EASA has updated the instructions on cleaning. At Finnair, for instance, the frequency of cleaning has been intensified, with special focus on high touch surfaces.
We also provide customers with sanitizing wipes, so that you can clean your table for example before eating. It is also a good practice to carry with your own hand sanitizer and disinfecting wipes when you travel, as it is not always possible to wash hands regularly during the trip.”
So the aircraft is not a very likely place to get a virus – but some people say they always get ill after flying, why is that?
“The cabin air is dry, and that can irritate mucous membranes in some people. But the incubation period of a respiratory virus varies from a few days to a week, so if you get a flu right after a flight, you most likely have caught it well before the flight.
Travellers have a higher risk of catching a viral infection in public transportation or at airport when touching surfaces that many people touch. That is why it is important to wash your hands and avoid touching your own face. “
What can I as a passenger do to ensure my safety on board during the coronavirus pandemic?
First of all, passengers with any signs of a respiratory tract infection can be denied boarding the flight, so do not travel if you feel unwell.
Secondly, physically distancing the passengers at the airport (e.g. at check-in, security checks, boarding gate, baggage retrieval) and during the boarding and deplaning is likely to achieve significant risk reduction.
In the aircraft maintaining physical distance is not always possible. The solution then – as recommended also by EASA - is requiring passengers wear masks during the flight to tackle the risk of asymptomatic carriers transmitting the virus. Masks have been obligatory on Finnair flights since May 18th.
Adhering to the recommended means of reducing the risk of SARS-CoV-2 transmission -- physical distancing, good hand hygiene and not travelling when you are ill -- you can be confident in the safety of air travel even during the pandemic.
The list of references can be obtained from the author by emailing firstname.lastname@example.org
2) Schwartz KL, Murti M, Finkelstein M, et al. Lack of COVID-19 transmission on an international flight. CMAJ 2020 Apr 14; 192: E410.doi: 10.1503/cmaj.75015