Health officials in New Zealand, a country that has a strict 14-day quarantine for arriving passengers, published on Friday a case detailing the risks of long-haul travel during a coronavirus pandemic – even if negative coronavirus tests are needed before the flight.
The report details a coronavirus outbreak linked by DNA analysis to a single passenger on an 18-hour flight from Dubai to New Zealand in September. A passenger who tested negative for coronavirus with a polymerase chain reaction (PCR) test within 48 hours of the flight was infected but had symptoms on board the aircraft and infected at least four other passengers.
There were a total of seven cases involving the flight, which had 86 passengers on board.
“By combining information on disease progression, travel dynamics and genomic analysis, we conclude that at least four cases of in-flight transmission of SARS-CoV-2 are likely to have occurred,”
New Zealand’s quarantine protocols make the study a unique analysis, as all passengers were monitored and retested during the required 14-day quarantine accommodation, which is managed by the New Zealand authorities. Most flights, doctors said, have no way of observing passengers two weeks after their journey.
“This case shows how difficult it is to keep infected people out of flight, even if you do PCR tests in a narrow pre-flight window,” said David Friedman, an infectious disease specialist at the University of Alabama at Birmingham, who reviewed the report. he told The Washington Post.
“The initial case most likely became contagious after taking the prepress test, but was actually symptomatic only 71 hours after the flight,” Friedman said. Coronavirus PCR tests are estimated to be about 98 percent effective in detecting coronavirus, which is why they are required by many countries to enter.
Of the seven infected individuals, five had a negative test within 48 hours before the flight. The authors of the article say that “transmission events occurred despite reports of the use of masks and gloves in flight” and that the airline operating the flight required strict camouflage.
Friedman said the duration of the flight may have affected the camouflage: “It would be really difficult for people to keep their masks on for all 18 hours.”
The evidence contradicts an October study by the Ministry of Defense, which suggested that an infected person would have to sit next to a passenger for at least 54 hours to infect them, and declared the risk of transmitting coronavirus to aircraft “low.” It also raises questions about the efficiency of high-efficiency air filtration in aircraft, which airlines believe keep passengers safe.
“These seven cases were found to be located in four rows one during the approximately 18-hour flight,” the study said. “Recent studies have presented conflicting findings about the risks associated with in-flight transmission. Therefore, we undertook a comprehensive investigation to determine the potential source of infection. “
The aircraft, a Boeing 777, is of the same type used in the Department of Defense study to determine aerosol transmission of the virus is unlikely.
“For both 777 and 767 aircraft, the measured concentrations showed that the aircraft cabin air system was extremely effective in reducing aerosol particle concentrations in passenger breathing areas,” the Department of Defense wrote. “Subsequently, the risk of exposure due to aerosols is low.”
Transatlantic flights, which require a rapid pre-flight antigen test, are also available recently, but rapid tests are only about 70 percent as effective.
On Thursday, the Centers for Disease Control and Prevention recommended not traveling on Thanksgiving by air and train in the United States, where new coronavirus infections are rising to record levels.
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