Researchers in Germany have found possible evidence of the spread of coronavirus on a four-hour flight.
In March, early in the pandemic, two airline passengers developed coronavirus infections after sitting through a nearly five-hour-long flight, the researchers said.
It all started with an infected hotel manager. A week before the flight, 24 travelers had contact with a hotel manager who later tested positive for Covid-19, according to research published in the journal JAMA Network Open on Tuesday.
They all were among 102 passengers on the four-hour 40-minute Boeing 737-900 flight from Tel Aviv to Frankfurt. None of the passengers had received Covid-19 diagnoses before the flight. That early on in the pandemic, there were no mitigation measures in place and passengers were not asked to wear masks.
Researchers from the Institute for Medical Virology at Goethe University in Frankfurt, Germany examined 24 patients from a tourist group and tested them for coronavirus. Most of the other passengers were also contacted four to five weeks later for interviews.
Seven members of the tourist group tested positive for Covid-19. Four were symptomatic during the flight, two were presymptomatic and one remained asymptomatic, according to the researchers.
“We discovered 2 likely SARS-CoV-2 transmissions on this flight, with seven index cases,” the researchers wrote. The two people who may have been infected on the flight were sitting at the back of the plane, directly across the aisle from the seven infected passengers seated in a cluster.
“These transmissions may have also occurred before or after the flight,” the researchers wrote.
Just over 90% of the other flight passengers completed interviews with the researchers. One passenger reported testing positive for Covid-19 four days after the flight, but did not recall having any symptoms.
“The airflow in the cabin from the ceiling to the floor and from the front to the rear may have been associated with a reduced transmission rate,” the researchers wrote. “It could be speculated that the rate may have been reduced further had the passengers worn masks.”
The risk of transmission on a plane depends on a number of factors, including closeness to an index patient and movement of passengers and crew.