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COVID-19 can spread on flights, 2 studies trace positive cases

COVID-19 can spread on flights, 2 studies trace positive cases
Posted at 2:20 PM, Sep 22, 2020
and last updated 2020-09-22 18:46:48-04

Two studies recently published in the CDC’s journal indicate COVID-19 can spread on airplanes.

In one study, researchers found a woman showing symptoms on a 10-hour flight potentially spread COVID-19 to at least 15 other people on the plane.

A 27-year-old businesswoman who lived in London and was from Vietnam started having symptoms, fever and cough, while still in London in late February. She and her sister had visited Italy and other locations in London before the woman flew to Vietnam. Her sister later tested positive for COVID-19.

The 27-year-old was one of 21 people sitting in business class on the March 1 flight from London to Hanoi, Vietnam. The woman became more sick once she landed, and isolated in her home. A few days later, she tested positive for COVID-19, as did three people in her house and a friend back in London she had visited before the flight.

Researchers quickly tracked down the majority of people who were on the woman’s flight to isolate and trace potential cases.

In all, researchers identified 14 additional passengers and one crew member who had COVID-19. The study states 12 of the passengers who tested positive had sat in business class with the 27-year-old woman, and 11 of them were sitting within two seats of her.

“First, thermal imaging and self-declaration of symptoms have clear limitations, as demonstrated by case 1 (the woman), who boarded the flight with symptoms and did not declare them before or after the flight. Second, long flights not only can lead to importation of COVID-19 cases but also can provide conditions for superspreader events,” researchers concluded.

The second study looked at four people aboard a flight from Boston to Hong Kong on March 9 who all tested positive for COVID-19 after landing in Hong Kong and showing symptoms. Two passengers, a couple, flew in business class. They showed symptoms the day they landed and sought healthcare.

The other two cases were flight attendants who served the business class and first class sections of the plane. Both had come into close contact with the couple, and they both developed symptoms a few days after landing.

Researchers were able to sequence their viruses and discovered all four had the same strain of COVID-19.

Scientists conclude the couple contracted COVID-19 while they were in the U.S. and transmitted it to the flight attendants on the plane.

“Passengers and cabin crew do not generally go through the same check-in process at airports before boarding. Although we cannot completely rule out the possibility that (the flight attendants) were infected before boarding, the unique virus sequence and 100% identity across the whole virus genome from the 4 patients makes this scenario highly unlikely,” researchers stated.

Although there were no other positive COVID-19 cases reported from this flight, not all passengers were tested or tracked like in the first study.

“Our results demonstrate that SARS-CoV-2 can be transmitted on airplanes. To prevent transmission of the virus during travel, infection control measures must continue,” they noted.

Both of these studies looked at cases on flights before face coverings were mandatory on flights. They were published in Emerging Infectious Diseases, a journal of the Center for Disease Control and Prevention.