People wait to enter a tent erected to test for coronavirus at the Brooklyn Hospital Center in Brooklyn, New York, March 19, 2020. (Andrew Kelly/Reuters)

Last updated March 21, 9am EST

Ten American states now have more than 500 confirmed cases of coronavirus. In comparison, twelve Chinese clusters reached 500 cases (according to the available data, which is by no means totally trustworthy). Most of the outbreaks outside of Wuhan seem to have been contained early, whereas in the U.S., the number of cases within each cluster continues to grow exponentially. New York remains the epicenter of the domestic outbreak, with more than 11,000 confirmed cases. However, New York is carrying out more tests per capita than other states, so the numbers don’t necessarily reflect the severity of each statewide outbreak. Fifty-five percent of those infected in New York are between the ages of 18 and 55, which, while troublesome, bodes well for the death rate, as COVID-19 is most deadly in elderly populations. New York governor announced that he would send 1 million N95 facemasks to New York City and would continue purchasing medical resources, such as ventilators, to combat the virus.

After initial obstacles, the U.S. has succeeded in massively increasing its testing capacity. Over the past few days, the number of tests administered domestically has grown by nearly 40 percent each day. Yesterday, the FDA approved a test that could diagnose coronavirus in just 45 minutes. As the U.S. ramps up its ability to diagnose the virus, the most severe social-distancing measures could possibly be rolled back, but only if authorities pair testing efforts with tracing efforts, ensuring that those tested remain in strict quarantine. We’ll be watching tracing measures in the next few days to see whether states can capitalize on testing to reduce lockdowns.

The death toll continues to be severe in Italy. Seven hundred ninety-three people died yesterday alone, and the growth in the number of dead has been consistent over the past few days, meaning the national lockdown has not yet “flattened the curve” of deaths. One caveat: The high death rate in Italy may reflect the way in which Italian hospitals determine cause of death. An Italian doctor told the Telegraph that “all the people who die in [Italian] hospitals with the coronavirus are deemed to be dying of the coronavirus.” Other countries may attribute those deaths to preexisting conditions. “On re-evaluation by the National Institute of Health, only 12 per cent of death certificates have shown a direct causality from coronavirus, while 88 per cent of patients who have died have at least one pre-morbidity — many had two or three,” the doctor continues. Still, the devastation is harrowing and shows no signs of abating.

The rate of new cases in the U.S. and U.K. remains staggeringly high compared with other countries’ at the same point in their outbreaks, whereas France seems to have succeeded in slowing down transmission over the past few days. One simple but crucial takeaway from the curves below is that masks are effective. Southeast Asian countries, many of whose residents were already accustomed to wearing masks, have rationed huge numbers of masks since January, and have seen remarkably low rates of infection. In the U.S., officials warned against purchasing masks, with some news reports saying masks don’t protect people. Perhaps this was a noble lie to direct masks to medical workers who need them most, but we’ll need to ramp up the civilian use of face masks to slow the spread of coronavirus.