Here's one source: https://www.washingtonpost.com/health/2020/02/25/cdc-coronav...
> While South Korea has run more than 35,000 coronavirus tests, the United States has tested only 426 people, not including people who returned on evacuation flights.
> While South Korea has run more than 35,000 coronavirus tests, the United States has tested only 426 people, not including people who returned on evacuation flights.
This bit seems important. The “only 400 tested!” statistic people are citing seems much more reasonable in this context.