German researchers have found possible evidence of the spread of the coronavirus during a four-hour flight.
In March, at the start of the pandemic, two airline passengers developed coronavirus infections after witnessing a nearly five-hour flight, researchers said.
It all started with an infected hotel manager. A week before the flight, 24 travelers had contact with a hotel manager who then tested positive for Covid-19, according to a study published Tuesday in the journal JAMA Network Open.
They were all among 102 passengers on the four-hour, 40-minute Boeing 737-900 flight from Tel Aviv to Frankfurt. None of the passengers had been diagnosed with Covid-19 before the flight. At the start of the pandemic, no mitigation measures had been put in place and passengers were not advised to wear masks.
Researchers at the Institute of Medical Virology at Goethe University in Frankfurt, Germany, examined 24 patients from a tour group and tested them for the coronavirus. Most of the other passengers were also contacted four to five weeks later for interviews.
Seven members of the tourist group have tested positive for Covid-19. Four were symptomatic during the flight, two were presymptomatic and one remained asymptomatic, the researchers said.
“We discovered 2 probable transmissions of SARS-CoV-2 on this flight, with seven index cases,” the researchers wrote. The two people who may have been infected during the flight were seated in the back of the plane, directly across the aisle from the seven infected passengers seated in a group.
“These transmissions may also have taken place before or after the flight,” the researchers wrote.
Just over 90% of other air passengers conducted interviews with the researchers. A passenger said he tested positive for Covid-19 four days after the flight, but could not recall any symptoms.
“Airflow in the cabin from ceiling to floor and front to back may have been associated with a reduced transmission rate,” the researchers wrote. “One would assume that the fare could have been reduced further if the passengers wore masks.”
The risk of transmission on board an aircraft depends on a number of factors, including proximity to an index patient and the movement of passengers and crew.