i dont think it is mate. i dont think they spread parvo when they have had the jab.
a lad i know had a litter of pups about 3 years ago and was stuggleing to to sell them, he wanted to keep one but was worried about them getting parvo as they were getting on a bit. i asked my vet if he could just jab the one pup he was keeping and leave the others without it spreading through the rest of the litter. to which my vet replied he could the others would not catch it. the lad jabbed the pup and kept it in with the rest of the litter and they were all fine.
Why didnt he just jab the whole lit