A study published by the Korean Centers for Disease Control and Prevention suggests that travellers with no symptoms of COVID-19 could spread the coronavirus on flights.

The study found that, on a flight with 290 passengers, a passenger appeared to contract the new coronavirus from one of the six asymptomatic travellers.

We must improve flight safety

The researchers note that the use of masks on board flights is crucial to prevent the spread of the virus, along with hand hygiene, surface disinfection and work to limit contact during boarding and disembarking.

In the study, before boarding, medical workers examined the 310 people scheduled to fly; 11 people who showed symptoms did not board the plane. Each passenger was issued an N95 mask, and staff members followed strict infection control procedures at the airport and in the air.

When the flight landed, the 299 passengers were quarantined by the government for two weeks and were regularly tested for COVID-19. Six passengers, who were asymptomatic, tested positive at the beginning of the quarantine. At the end of the quarantine, a passenger tested positive after previously testing negative.

That passenger was sitting three rows ahead of the asymptomatic and had used N95 for the entire flight, except to eat and use the bathroom. The asymptomatic patients used the same bathroom during the flight.

Due to strict infection control and post-flight quarantine, the researchers concluded that the newly infected patient had likely contracted the virus during the trip. A validation study looking at a second flight found the same result, with three asymptomatic patients likely infecting another passenger.