There's a meme floating around that basically says:

"Before I had kids, I thought I had a great immune system, but it turns out I was just really good at staying away from the type of people who sneeze directly into your eyeballs while telling you a story."

There's some truth to that If you can avoid most people during your normal routine, you won't be exposed to much. The normal flu has an R0 of 1.3ish? This virus is at least twice that, so it takes a lot less to catch.