Health officials in New Zealand, a country that has a strict 14-day quarantine in place for arriving travelers, published a case study on Friday describing the risk of traveling on long-haul flights during the coronavirus pandemic – although negative coronavirus tests are required before the flight.
The report describes a coronavirus outbreak linked via DNA analysis to a passenger on an 18-hour flight from Dubai to New Zealand in September. The traveler who tested negative for coronavirus with a polymerase chain reaction (PCR) test within 48 hours of the flight was contagious but pre-symptomatic on board the aircraft and infected at least four other passengers.
In total, there were seven cases related to the flight, which had 86 passengers on board.
“By combining disease progression, travel dynamics, and genomic analysis information, we conclude that at least four in-flight transmission events of SARS-CoV-2 were likely to occur,”
New Zealand’s quarantine protocols make the investigation a unique analysis because all passengers were monitored and tested again during their required 14-day quarantine accommodation, which is managed by the New Zealand authorities. Most flights, doctors have pointed out, have no way of monitoring passengers two weeks after their journey.
“This case talks about how difficult it is to keep infected people away from a flight, even if you perform PCR tests in a narrow time window before the flight,” said David Freedman, an infectious disease specialist at the University of Alabama in Birmingham, who reviewed the report. , told The Washington Post.
“The original case probably became contagious after he took the preflight test, but in fact it was not symptomatic until 71 hours after the flight,” Freedman said. PCR coronavirus testing is estimated to be approx. 98 percent effective at detecting coronaviruses, which is why they are required by many countries for entry.
Of the seven infected individuals, five had tested negative within 48 hours prior to the flight. The authors of the article say that “transmission incidents occurred despite reported use of masks and gloves during flight” and that strict masking was required by the airline operating the flight.
Freedman points out that flight time may have had an impact on masking: “It would have been very difficult for people to keep their masks on for a full 18 hours.”
The evidence contradicts an October Ministry of Defense study that suggested an infectious person should sit next to a passenger for at least 54 hours to infect them, declaring the risk of coronavirus transmission in the planes “low.” It also raises questions about the effectiveness of high-efficiency air filtration on aircraft, which airlines have credited for keeping passengers safe.
“These seven cases were found to have been located within four rows of each other during the approximately 18-hour flight,” the investigation says. “Recent studies have presented conflicting findings of the risks associated with in-flight transmission. We therefore conducted a comprehensive study to determine the potential source of infection. ”
The aircraft, a Boeing 777, was of the same type used in the Department of Defense’s investigation to determine aerosol transmission of the virus was unlikely.
“For both 777 and 767 fuselages, the measured concentrations showed that the aircraft’s cabin system was extremely effective in reducing the concentration of the aerosol tracking particle in the passenger’s breathing zones,” the Ministry of Defense wrote. “Subsequently, the risk of exposure due to aerosols is low.”
Transatlantic flights that require fast antigen test flight have also become available recently, but fast tests are only about 70 percent as effective.
On Thursday, the Centers for Disease Control and Prevention against Thanksgiving recommended traveling by plane and train in the United States, where new coronavirus infections are rising to record levels.
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