Time and again

摘要

HOW AND when it infected the first human being, by making the jump from an animal, is anybody's guess. But one thing is certain about the new coronavirus which was discovered in December in China and is now causing a global scare: it is a known unknown. And this, along with the health authorities' response so far, is mostly good news. People's fear is understandable. As The Economist went to press, over 600 cases had been confirmed in six countries, of which 17 were fatal. The new virus is a close relative of sars (severe acute respiratory syndrome), which emerged in China in 2002 and terrorised the world for over half a year before burning out. sars afflicted more than 8,000 people and killed about 800, leaving in its wake $3obn-ioobn of damage from disrupted trade and travel (see China section).