If you have a deck with 2 hearts and 10 spades, your first flip could very well be a heart, even if with enough flips, 10/12 are spades.

What I mean by this is that viruses may have arbitrary behaviour when the infected population is small. Let's say as of September 2019, five people in the world were infected with COVID. It's actually not improbable or crazy that the epidemic outbreak only started in Dec/Jan.