An ‘unprecedented’ global health challenge

The top U.S. health official warned that the coronavirus outbreak, which has already sickened nearly 80,000 people in 37 countries, could hit the country hard, as chaos in the rest of the world drew attention to the need for a global game plan.

“We cannot hermetically seal off the United States to a virus,” the official, Alex Azar, said. “And we need to be realistic about that.”

The emergence of Italy, Iran and South Korea as new hubs for the virus shifted the focus in many countries from prevention to reaction. A 14-day isolation period has become standard, but that can be difficult to implement, and its effectiveness has been called into question.

Restricting the movement of goods and people seemed to have worked in China, where the rate of new infections has plunged, according to the World Health Organization — though the economic ramifications of those measures remain to be seen. South Korea has tried something entirely different, warning residents while keeping businesses running.