This artificially low number means that for the past few weeks, we’ve seen massive state action abroad and only simmering unease domestically. While Chinese officials were enacting a world-historic containment effort—putting more than 700 million people under some kind of movement restriction, quarantining tens of millions of people, and placing others under new kinds of surveillance—and American public-health officials were staring at the writing on the wall that the disease was extremely likely to spread in the U.S., the public-health response was stuck in neutral. The case count in the U.S. was not increasing at all. Preparing for a sizable outbreak seemed absurd when there were fewer than 20 cases on American soil. Now we know that the disease was already spreading and that it was the U.S. response that was stalled.

Meanwhile, South Korean officials have been testing more than 10,000 people a day, driving up the country’s reported-case count. Same goes for Italy: high test rate, high number of cases. (Now some Italian politicians want to restrict testing.) In China, the official data say the country has more than 80,000 cases, but the real number might be far, far higher because of all the people who had mild(er) cases and were turned away from medical care, or never sought it in the first place. That may be cause for reassurance (though not everyone agrees), because the total number of cases is the denominator in the simple equation that yields a fatality rate: deaths divided by cases. More cases with the same number of deaths means that the disease is likely less deadly than the data show.