The 44-year-old man was chatting with his wife and son on a flight from Singapore to China earlier this year when he let his guard down, allowing his face mask to slip below his nose.
That lapse appears to have been how he became infected with Covid-19.
The case, cited in a recently published study of an outbreak among passengers on a January flight, is one of the first to document a probable transmission on an airliner and is reviving calls for government rules requiring masks. It comes as safety concerns raise questions about whether passengers will return in sufficient numbers to keep airline companies from collapsing.
Lawmakers and airline unions—which have sought more rigorous standards for months as infections surge across the nation and reports circulate of passengers skirting existing rules—said the study adds new weight to their demands.
“This report seems to confirm the tragic consequences of the Trump administration’s abject failure to protect passengers by mandating masks,” said Senator Richard Blumenthal, a Connecticut Democrat. “Wearing masks, like requiring seat belts or banning smoking, is absolutely fundamental to protecting passengers and crew during these unprecedented times.”
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The head of a union representing flight attendants—the workers most exposed to passengers and who are called on to enforce airline mask directives—called the lack of action “inexcusable.”
“This new study underscores the urgent need for a single national policy that would mandate that masks be worn, and worn properly, on all commercial flights,” said Julie Hedrick, president of the Association of Professional Flight Attendants at American Airlines Group Inc.
All major U.S. airlines now require passengers to cover their faces, but advocates for a federal mask requirement say it would make enforcement easier, potentially making violations a crime. It would also set a more uniform standard, they say. The Department of Transportation earlier this month released a 44-page set of guidelines for airlines and airports that urges mask usage, but officials have repeatedly said they don’t favor legal requirements.
The airline industry is facing a crisis as passenger counts, which plummeted to about 5% of pre-pandemic levels in April, started coming back but stalled in recent weeks at about 25%, according to Transportation Security Administration data. Companies have warned of possibly tens of thousands of layoffs once restrictions tied to initial federal aid expire on Sept. 30.
President Donald Trump has rarely worn a mask and some of his allies bitterly oppose mandatory orders for them, though he declared his support for face coverings in briefings last week.
“The Department of Transportation and FAA have been clear that passengers should wear face coverings while traveling by air, for their own protection and the protection of those around them,” the Federal Aviation Administration said in a statement.
The trade group for large carriers, Airlines for America, said: “U.S. airlines are continuing to take extraordinary measures as part of a multilayered approach to help protect the health and well-being of the traveling public and employees.”
Air travel presents unique risks for contracting the virus because conditions are so crowded. Research has shown airborne diseases such as Covid-19 can be transmitted on planes, but risks aren’t well quantified.
The Jan. 24 flight from Singapore to Hangzhou, China is the most thoroughly documented case of a likely passenger-to-passenger infection of Covid-19 to date.
About 100 of the 335 passengers had recently traveled to Wuhan, China, where the disease erupted originally, and a handful exhibited symptoms. As a result, everyone was quarantined for at least two weeks. They were questioned in detail by infectious disease experts. The peer-reviewed results of the study were published online July 6 by the journal Travel Medicine and Infectious Disease.
The team in China concluded that one man most likely became infected by fellow passengers after ruling out other possible contacts and noting the timing of when he became ill.
For an hour of the flight, he went to talk with his wife and son, who were in a different row.
“While he talked, he reported that he did not wear his mask tightly, and his nose was outside of mask,” the authors wrote.
Two people adjacent to him in the same row and two more across the aisle in the row directly behind tested positive for Covid-19, including one was already showing symptoms, the study found.
Ashok Srinivasan, a computer science professor at the University of West Florida who specializes in modeling disease transmission and has studied airline travel, said the paper highlights the importance of masks in preventing the spread of the coronavirus in crowded environments.
“I think it is important to wear the mask all the time,” Srinivasan said.
The study’s authors said the 15 other passengers who got Covid-19 were infected while in Wuhan or by close contacts with family members or others.
The aircraft, a Boeing Co. 787-9, is equipped with filters that remove the virus from recirculated air and that may have lowered the chances that others became infected, the authors said. All modern jetliners have such filters.
The study acknowledged the researchers couldn’t completely rule out whether the man had been infected elsewhere, but said the evidence suggests “he probably acquired SARS-CoV-2 infection during the flight.”.
The leaders of two House committees overseeing transportation policy have inserted language requiring the government to adopt strict mask standards into separate bills. The bills have yet to be taken up by the Senate.
Representative Peter DeFazio, the chairman of the Transportation and Infrastructure Committee, called the study “intriguing,” but said enough doubt remains that the FAA should conduct its own research.
“That’s why I’ve repeatedly pressed the FAA to not only commission its own study to better understand how the virus travels within the airplane cabin, but also to mandate masks,” DeFazio, an Oregon Democrat, said in a statement.
Representative David Price, the North Carolina Democrat who heads the Appropriations Committee panel overseeing transportation spending, said in an interview that a federally mandated mask rule is needed to set “an example for the entire country.”