Scientists uncover ancient coronavirus epidemic in East Asia., page-64

There may be some truth to this, because when the ice from a long term ice age thaws, viruses are released.
And within a few hundred years the ice thawed and it became much hotter that it is now.
Below is what happened 20,000 years ago.

• What Thawed the Last Ice Age? - Scientific American
  
  https://www.scientificamerican.com/article/what-thawed-the-last-ice-age
  4/4/2012 · Roughly 20,000 years ago the great ice sheets that buried much of Asia, Europe and North America stopped their creeping advance. Within a few hundred years …
  • Estimated Reading Time: 7 mins