Flying presents a lower risk of Covid-19 than grocery shopping or dining out, a Harvard study released by Delta Air Lines concludes.

The use of face masks is “the most essential part of a comprehensive set of measures to reduce Covid-19 during air travel,” scientists found.

The research by Harvard’s T H  Chan School of Public Health is claimed to be the most comprehensive study to find that the approach US airlines have taken to protect passengers and staff from Covid-19 means the risk of exposure during air travel is “very low”.

The report concludes that the universal use of face masks, diligent cleaning protocols and advanced ventilation and filtration systems offer significant protection against the virus, lowering the risk of transmission on an aircraft to minimal levels.

The study suggested it takes a “combination of layered infection control measures” to reduce the risk of Covid-19 transmission.

“The risk of Covid-19 transmission on board aircraft [is] below that of other routine activities during the pandemic, such as grocery shopping or eating out,” according to the Harvard study.

“Implementing these layered risk mitigation strategies…requires passenger and airline compliance [but] will help to ensure that air travel is as safe or substantially safer than the routine activities people undertake during these times.”

The US Centers for Disease Control and Prevention (CDC) has not confirmed a single case of transmission on a US aircraft.

The Harvard research team noted the “highly effective ventilation systems” on aircraft, which mitigate disease exposure by rapid and continuous filtering and exchange of cabin air.

Delta was one of the first airlines to require travellers and employees to wear a mask or face covering at airports and on board aircraft.