“It is not surprising that we have seen additional cases today. The estimate from our work at Imperial College London is that about 1% of infections with the virus responsible for covid-19 are fatal, so the total of 12 deaths to date in Italy suggests many more than the 470 cases detected so far.
Our best estimate would be over 1000 cases. Each undetected case creates at least the potential for onward spread. This combined with frequent travel to and from affected regions, means that all countries are at risk of detecting cases both in travellers and those they came into contact with.”