A woman may have contracted the coronavirus in an airplane bathroom, researchers say.

Researchers say they have evidence that a woman contracted the coronavirus on a flight, perhaps in the bathroom on the plane.

The 28-year-old woman was among 300 South Koreans evacuated from Italy at the height of the coronavirus pandemic in Milan in March, the researchers wrote in the U.S. Centers for Disease Control and Prevention’s journal Emerging Infectious Diseases. (CDC).

“On the flight from Milan, Italy, to South Korea, he was wearing an N95 mask, except when using the bathroom,” they wrote.

“The bathroom was shared by passengers sitting nearby, including one asymptomatic patient. She was sitting three rows away from the asymptomatic patient,” they added.

The South Korean officials who organized the flight had implemented comprehensive infection control measures and had examined everyone before boarding. All passengers and crew were also quarantined when they arrived in South Korea. Six passengers tested positive shortly after their arrival in South Korea.

The 28-year-old woman developed symptoms eight days after she arrived home and was hospitalized.

“Since she did not leave and was quarantined for three weeks alone at her home in Italy before the flight and did not use public transportation to get to the airport, it is very likely that her infection was transmitted on the flight through indirect contact with an asymptomatic patient,” wrote the researchers from Soonchunhyang University School of Medicine in Seoul.

There has been very little evidence on whether people can contract the coronavirus on a flight, although many airlines have policies that leave more room for passengers, clean planes more frequently, and encourage passengers to stay in their seats and not move around the plane. Evidence already shows that airplane ventilation systems clean the air quickly and completely.

“This study was one of the first to evaluate asymptomatic covid-19 transmission in an aircraft. Previous studies of in-flight transmission of other respiratory infectious diseases, such as influenza and severe acute respiratory syndrome, revealed that sitting near a person with an infectious disease is an important risk factor for transmission similar to our own findings,” the researchers wrote.

The researchers said that many precautions were taken by the officials who organized the flight.

“When passengers arrived at the Milan airport, medical personnel conducted physical examinations, medical interviews, and body temperature checks outside the airport before boarding, and 11 symptomatic passengers were removed from the flight,” they wrote.

The passengers were issued N95 respirators (masks that have been shown to protect the wearer from viral infection) and kept at a distance of two meters before boarding.

“Most passengers wore N95 respirators, except at mealtimes and when using the restroom during the flight. After an 11-hour flight, 299 asymptomatic passengers arrived in South Korea and were immediately quarantined for two weeks in a government quarantine facility where the passengers were completely isolated from each other. Medical personnel examined them twice daily for elevated body temperature and covid-19” symptoms.

Researchers in Germany reported earlier this month that two people may have been infected before, during, or after a flight from Tel Aviv to Frankfurt in March.

They were sitting near the back of the plane, directly across the aisle from seven passengers who later turned out to be infected.

By Maggie Fox – CNN