Wearing masks to prevent the spread of the coronavirus was not widespread in March, when a group of German tourists took a long flight home from Israel – but researchers were surprised that only two passengers outside the group were infected.
In a short study published Tuesday in the American medical journal JAMA Network Open, virologists at a university hospital in Frankfurt, Germany, made close contact with all the passengers of the flight – none of whom were wearing masks at the time – to to investigate the real risk by the presence of travelers infected with COVID-19.
On March 9, 102 passengers boarded the four-hour, 40-minute flight from Tel Aviv-Frankfurt, including a group of 24 tourists.
German authorities were warned that the group came into contact with an infected hotel manager in Israel, and decided to test the 24 tourists upon their arrival in Frankfurt.
Seven of their tests tested positive, as did seven later.
Four to five weeks later, investigators contacted the 78 other passengers on the flight, 90 percent of whom responded. The researchers asked them who they came in contact with and what symptoms they had, and tested several of them.
They found two passengers were likely to be infected during the flight: the two people were sitting across the hallway from the original seven cases.
For respiratory viruses, experts traditionally consider the infection zone in an airplane to extend two rows of seats in front of the infected person and two rows behind.
But shockingly, a person sitting in the row (seat 44K) directly in front of two of the infected tourists (seats 45J and 45H) was not infected.
“This person from row 44 told us he had a long conversation and a long time talking to both of row 45,” Sandra Ciesek, head of the Institute of Medical Virology in Frankfurt, told AFP, noting that it made it all the more surprisingly he was not infected.
The two passengers who were sitting directly behind another infected tourist also did not contract COVID-19.
“We were surprised to find only two probable broadcasts,” said Sebastian Hoehl, of the same Frankfurt Institute.
All other passengers were not tested, so investigators could not rule out that some of them may have been infected. The study emphasizes that in any case viral transmission on an aircraft is indeed possible if passengers do not wear masks.
However, Hoehl notes, “because the fare was lower than we expected, and because none of the passengers wore masks, I think it’s reassuring that we could not track down any more” cases.
The investigators also said that several investigations into repatriation flights from Wuhan, China at the beginning of the pandemic found that no transmissions were on board while passengers were masked.
© 2020 AFP
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