A woman is thought to have caught the coronavirus from an asymptomatic passenger aboard the same flight.
As lockdown continues with ease, the UK Foreign Office has relaxed its advice on “essential travel only”.
While holidays in Spain, France or Croatia must be followed by a 14-day quarantine, Britons are free to visit Greece, Italy, Australia and Cuba, to name a few destinations.
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According to government guidelines, airlines must “formally advise” customers not to travel if they develop symptoms of coronavirus – namely fever, cough, or loss of taste or smell.
However, scientists at Soonchunhyang University in Seoul have revealed that a woman probably caught the infection while on board a flight with a passenger who showed no signs of the coronavirus.
The woman, who was sitting three rows behind the infected passenger, is thought to have been infected while using the toilet – the only time she removed her mask.
Toilet ‘most plausible explanation for transfer’
The proportion of asymptomatic patients was debated early in the outbreak.
On March 3, the director general of the World Health Organization Dr Tedros Adhanom Ghebreyesus said: “Evidence from China is only 1% of the reported cases have no symptoms and most of these cases develop symptoms within two days”.
Scientists from the University of Hong Kong later claimed that 12.1% of patients do not develop a fever.
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When it comes to these individuals spreading the virus, it has been argued that those who do not cough or sneeze – the main routes of transmission – would be expected to transmit the infection to fewer people.
It has been suggested, however, that most people who appear asymptomatic actually have “really mild illness”.
To better understand the risk of asymptomatic flyers, Soonchunhyang scientists looked at a March 31 flight from Italy to South Korea.
Of the 310 passengers were later confirmed to be flying with an asymptomatic coronavirus infection.
Prior to take-off, passengers underwent a physical examination, medical interview and temperature check at Milan Airport.
Eleven people were not allowed to step in after showing symptoms.
In the waiting area, masks were distributed and the passengers kept 2m (6.5ft) apart.
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Once on board, most passengers wore masks unless they were eating or using the toilet.
At the end of the 11-hour flight, the passengers were immediately quarantined for 14 days at a government facility.
On day one of quarantine tests six positive for the coronavirus, have caught it before flying. On day 14, these patients still showed no signs of infection and were declared asymptomatic.
Also on day 14, a 28-year-old woman tested positive for the coronavirus.
She reportedly wore a mask with her on board, except when using the toilet, which is also known to be used by one of the asymptomatic passengers.
The woman sat three rows away from the same asymptomatic individual.
“Given that she did not go outside and was only quarantined for three weeks at her home in Italy before the flight and did not use public transport to get to the airport, it is very likely that her infection during the flight was indirectly transferred contact with an asymptomatic patient, ”the scientists wrote in the journal Emerging Infectious Diseases.
“They reported coughing, rhinorrhea [a runny nose] and myalgia [muscle pain] on quarantine day eight, and was transferred to a hospital on quarantine day 14. ”
The scientists concluded the “most plausible explanation for the transmission of [the coronavirus] “to a passenger on the plane, she is infected by an asymptomatic but infected passenger while using a toilet on board”.
It is unclear why the other passengers did not catch the infection.
The aircraft bathroom may be contaminated, with research suggesting that the coronavirus may survive on surfaces.
Studies also mean that the infection can spread through feces, a lesser route of transmission.
The scientists also saw 205 passengers making the same trip on April 3rd.
Three were asymptomatic, and tested positive only on the first day of quarantine. Another passenger changed negatively on day one, but positively on day 14.
The scientists “suspect that this infection was also transmitted by contact with inflight”.
Previous research suggests flu and severe acute respiratory syndrome (SARS) may be transmitted between airport passengers nearby.
This may be due to the limited space on board as contaminated surfaces.
Given their results, the scientists stressed the importance of hand hygiene, masks and social distancing when boarding and disembarking aircraft. This is repeated by the UK Government.
