The media regularly alarms Canadians by publishing stories about COVID-19 being detected on domestic and international flights in Canada.
The information about possible COVID exposure on a flight is correct. It comes from a government source.
However, it is less alarming than it looks.
Indeed, the information comes from a page put online several months ago by the Government of Canada, which publishes a list of each event or trip where cases of COVID-19 have been confirmed .
However, this detailed list is updated daily.
In other words: when, on a given day, a media outlet decides to report information based on data from this site, it is important not to conclude that there is a sudden outbreak of cases on domestic and international flights in Canada.
(Besides, since the list is updated daily, the media could just as easily have released this information the day before, the next day, the previous or next week!)
Risk of exposure does not equal transmission
The government page lists risk situations of exposure to COVID-19, but does not identify cases of transmission of the coronavirus between passengers.
Exactly how many cases of COVID-19 have been reported attributable to transmission between passengers on flights to or from Canada since the start of the pandemic?
None. Let's say it again: None.
Ottawa's new safety guide for air travel, Canada’s Flight Plan for Navigating COVID-19, released last Friday (Aug. 14th) confirms this notion.
"To date, the Government of Canada is not aware of any case attributable to transmission between passengers during flights to or from Canada," stated Transport Canada in a release detailing the new plan.
Very rare cases of transmission
Cases of disease transmission on an airplane are very rare, explains Air Canada in a publicly-available fact sheet.
"The reasons for the apparently low rate of in-flight transmission are not fully determined but are thought to include a combination of factors, such as the inherent characteristics of cabin air flow," the airline says.
Air Canada adds that scientific studies on communicable diseases and air transport also confirm that the risk of transmission on board an aircraft is minimal.
For example, the United States Centers for Disease Control and Prevention (CDC) says the majority of viruses and germs do not spread easily on an airplane due to air circulation and HEPA air filtration.
A survey confirms
An informal conducted by IATA from January to March 2020 with 18 major airlines also confirms the trend.
According to the survey, just three episodes of suspected in-flight transmission of COVID-19, all from passengers to crew, were found during this period.
A further four episodes were reports of apparent transmission from pilot to pilot, which could have been in-flight or before/after (including layover).
Notably, there were no instances of suspected passenger-to-passenger transmission found.
Air Canada points out that this survey was conducted before carriers largely put in place additional security measures in response to COVID-19 - the CleanCare+ program in the case of Air Canada.
However, the additional measures put in place by air carriers - such as the preliminary screening questionnaire, temperature measurement and compulsory face covering - are also considered effective in countering the risk of disease transmission on board.
It's also important to remember that Canada's Flight Plan presented last week recognizes that the biosecurity programs put in place by carriers and airports respect or exceed international measures in terms of health and safety.