Coronavirus Predictions Bedeviled by the Details

Until early this week, the U.K. government under Boris Johnson had been oddly relaxed in its response to the coronavirus pandemic. Unlike many other nations that had closed schools and restaurants and banned gatherings of even five people in an effort to curb the spread of Covid-19, the U.K. had allowed life to continue much as normal, only testing patients entering hospitals and requesting those with symptoms to self-isolate.

That's changed significantly, with the government now advising people to work from home and to avoid public transport and gatherings with friends and family; pubs, restaurants, gyms and movie theaters will be ordered to close. The about-face came after hundreds of scientists from around the world attacked the earlier policy as needlessly risky. And an epidemiological modeling group at Imperial College London — a key scientific resource for the government — revised its estimate of how soon serious cases would overwhelm the National Health Service, adding that the previous policy could have resulted in roughly 250,000 deaths.