Many years ago, I was doing the "right thing" and getting a dog from rescue. A south Texas rescue had a litter of puppies from a shelter, did I want one. I drove down to South Texas and got the ugliest beagle puppy I had ever seen. Within 12 hours it had diarrhea. Rushed to my vet, spend the weekend trying to keep it alive and ended up giving it back to rescue as I wasn't going through the pain of watching it die. It died. My vet and all the other experts told me not to bring another puppy into the house for a year.
It took me over 10 years to bring another puppy in the house, and that puppy had lived in a place that had dealt with parvo a year earlier. Every other dog I've gotten since then has been at least 6 months old.
To this day, I am very hesitant to even visit puppies.
Imagine when I found out local beagle breeders who do everything right have lost two five-month-old puppies to parvo. When they announced the second, my seven-month-old beagle boy went straight to the vet for a booster. Of course, this is the lady who got a measles shot when the local airport announced that they had a case of measles. Since he is entered in a dog show this month, I am not taking chances or waiting for a titer.