Ask HN: Why are people confident there will be a Covid-19 vaccine?

In discussions in the news, here on this board, and elsewhere, it seems there is a general presupposition that we will create a successful COVID-19 vaccine. People focus on when, not if.

Since there is some evidence that the virus is significantly mutating (e.g. the recent report from Los Alamos), and since we do not yet have vaccines I am aware of for any other coronavirus, what makes people so confident we will be able to produce working vaccine(s) for this one?