Four months after the coronavirus outbreak was declared a global health emergency, countries around the world have seen vastly different results from their efforts to fight the pandemic. Some have beaten an initial onslaught, some are in the middle of it, and some have yet to see, or at least report, that the virus is causing havoc. Factors both in and out of the control of individual countries have influenced their different outcomes so far. Here’s a breakdown of some things we’ve learned:

Early testing is paramount. Countries that rolled out good diagnostics in January -- including South Korea and Germany -- have managed their crises comparably well, since it enabled policy makers to react quickly to the growing threat and convinced people of the danger at hand. The picture was grimmer for countries that failed to put early testing into effect, including the U.S. There, the virus spread largely unchecked through February. When cases exploded, hospitals in hot-spots such as New York City were overwhelmed, states had to compete with each other for essential equipment, and citizens were subjected to conflicting, often highly politicized messaging about the stakes of the twin health-care and economic crises.