Thread by @yaneerbaryam

In-flight transmission despite required masks, gloves and pre-flight testing. @nntaleb

A traveler tested negative for covid-19 before a flight. He had the virus and infected 4 passengers.

washingtonpost.com/travel/2020/11…

"The study details an outbreak linked to one passenger on an 18-hour flight from Dubai to New Zealand in September.

The report details a coronavirus outbreak linked through DNA analysis to one passenger on an 18-hour flight from Dubai to New Zealand in September.

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"The traveler, who tested negative for the coronavirus with a polymerase chain reaction (PCR) test within 48 hours of the flight, was contagious but pre-symptomatic onboard the plane, and infected at least four other passengers.

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“By combining information on disease progression, travel dynamics and genomic analysis, we conclude that at least four in-flight transmission events of SARS-CoV-2 likely took place,”

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"New Zealand’s quarantine protocols make the study a unique analysis because all passengers were monitored and retested during their required 14-day quarantine managed by New Zealand authorities. Most flights have no way of monitoring passengers two weeks after their travel.

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“This case speaks to how hard it is to keep infected people off a flight, even if you do PCR testing in a narrow window of time before the flight, The original case most likely became infectious after he took the preflight test, but was not symptomatic until..after the flight

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"The evidence contradicts an October Department of Defense study that suggested a contagious person would need to sit next to a passenger for at least 54 hours to infect them, and declared coronavirus transmission risk on planes “low.”

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It also raises questions about the efficacy of high-efficient air filtration on planes that airlines have credited as keeping passengers safe..

The aircraft, a Boeing 777, was the same kind used in the Department of Defense study.

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“These seven cases were found to have been seated within four rows of each other during the approximately 18-hour flight,”

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Of the seven infected individuals, five had tested negative within 48 hours before the flight.. “transmission events occurred despite reported use of masks and gloves in-flight,” and that stringent masking was required by the airline operating the flight.

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"On Thursday, the Centers for Disease Control and Prevention recommended against Thanksgiving travel by air and train in the United States, where new coronavirus infections are rising to record levels.

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👉The article misstates the false negative rate, which is about 30%. The confusion is in the problem of sampling. Samples are 30% negative, and the test is reporting on the RNA in the sample.

nejm.org/doi/full/10.10…

@DrZoeHyde

"Cases A and B travelled together from Switzerland. Both cases reported negative test results in their country of origin at most 72 hours prior to boarding the flight. They departed Zurich, Switzerland and arrived in Dubai, UAE on 28 September 2020 at 08:02hrs."

Here is the testing and flight timeline