Key Point: It's been worse before.
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. During the 2009 influenza pandemic, the earliest reports listed 59 deaths from approximately 850 suspected cases, which suggested an extremely high case fatality of 7%.
However, the initially reported information of 850 cases was a gross underestimate. This was simply due to a much larger number of mild cases that did not report to any health system and were not counted. After several months – when pandemic data had been collected from many countries experiencing an epidemic wave – the 2009 influenza turned out to be much milder than was thought in the initial weeks. Its case fatality was lower than 0.1% and in line with other known human influenza viruses.