17 dead from 2019-nCoV

https://www.washingtonpost.com/world/asia_pacific/nine-dead-as-chinese-coronavirus-spreads-despite-efforts-to-contain-it/2020/01/22/1eaade72-3c6d-11ea-afe2-090eb37b60b1_story.html?outputType=amp
So far there might be thousands infected, are these numbers really something to be worried about? Even if mortality rate is low, could the virus mutate into something more deadly?
Also how come pneumonia is still so deadly as of 2020?

The WHO will have an emergency meeting later today, in Genova
what will they say about the virus?