I have an 8-week old cocker spaniel - poodle mix. I'm told she's had her first parvo shot out of three.
I live in a relatively well-to-do neighborhood with very, very few stray dogs. We have a front yard and a back yard, with the backyard completely gated and dog-proof. The gate joins the house where the front and back yard meet, probably about forty feet between the sidewalk/road and that gate.
For a couple reasons, we really didn't want to let the puppy go to the bathroom in the backyard a few minutes ago (minutes-old tree spray, probably innocuous but playing it safe).
We got lucky and the puppy didn't want to go to the bathroom before the spray dried out (really super hot here). But if she had (because this will probably come up again): What is the real chance my puppy gets parvo if I had let her relieve on my front lawn? How common is it among dogs, and do more dogs come that far up on my lawn than I think? How much does that first shot do?