Parvo kills more puppies in this country than anything else, and most of them were either unvaccinated or taken outside before the course was finished.
The part people get wrong is the window. A pup has some protection from its mother's antibodies, those antibodies fade at an unpredictable age, and until they do they also block the vaccine from working. That is why the course is a series of shots and not one, and why the pup is not protected until roughly two weeks after the last one.
Signs: vomiting, then bloody diarrhoea with a smell you do not forget, refusal to drink, and a puppy that goes flat very fast. Dehydration is what actually kills them.
Questions:
- What vaccination schedule did your vet put your pup on, and at what ages?
- If your pup survived parvo, what did the treatment involve?
- How long did you keep the pup indoors before its first walk?
Also worth saying loudly: a dog dewormed two to three weeks before its shots responds to the vaccine better, because a gut full of worms keeps the immune system busy.