Comparing to SARS (I was in Canada at the time) - quote from the article:
https://www.dw.com/en/will-mutations-soon-make-the-coronavirus-less-harmful/a-53839943

Mutated into oblivion: Mutations can even lead to a virus becoming so weak that it eventually disappears completely. This was the case, for example, with the severe acute respiratory syndrome (SARS) virus. Starting in November 2002, the first SARS pandemic spread from southern China to almost all continents within a few weeks. As the first pandemic of the 21st century, it aroused great fears among the global population. However, SARS ended up claiming only 774 lives worldwide within six months. By the summer of 2003, the number of newly infected persons worldwide was declining continuously, and in May 2004, the World Health Organization already declared this first SARS pandemic to be over.

My comment: Similarly to COVID-19 there was a lot of money invested in developing a vaccine. Eventually, the funding was pulled because there was no profit to be seen. Subsequently, there never was a vaccine against SARS, but a lot of money went down the drain.