(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.) As the new coronavirus continues to cross international borders, the two key questions on public health officials’ minds are: ‘How deadly is it?’ and ‘Can it be contained?’. The two outbreaks in recent memory that give the most insight into these questions are the 2002-2003 SARS outbreak, which spread from China to 26 other countries but was contained after eight months, and the 2009 H1N1 influenza pandemic, which originated in Mexico and spread globally despite all containment efforts. The severity and mortality of a novel emerging virus, which we scientists in this case are calling 2019-nCoV, are very difficult to judge when new data are coming in on a daily basis.