[Thread] By analyzing flight data and interviewing travelers, we get a better understanding of how the Covid-19 pandemic evolved:

Passenger volume was high on China-US flight routes in January when Chinese authorities were downplaying the severity... 1/5 https://nyti.ms/3bUTtQn 
2/5 ... of the coronavirus and no screening was in place. By Jan 17th when U.S. started to screen passengers from Wuhan, 4000 travelers had already taken direct flights from the city to NYC and SF.
3/5 Trump's China travel restriction significantly reduced the influx of travelers, but nearly 40,000 Americans & authorized travelers have still come in via direct flights since the order was enacted.

The screening process at arriving airports is spotty with minimal follow-up.
4/5 People evacuated from Wuhan were put under a mandatory quarantine; for other travelers from China, quarantine is advised but not enforced. It is challenging because the virus can spread even from asymptomatic & pre-symptomatic cases.
Last note: Although we mentioned this in the beginning of our piece, ppl may not read the article, so just reasserting:

Travelers are of multiple nationalities.

China-US routes are popular. The numbers are to help contextualize the scale of impact of authorities’ decisions.
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