It's good that you're concerned about your poor pup spreading this to other dogs (one way or another). It's a nasty disease and we wouldn't wish it on any dog. But there's a bit more to it than just how long your pup is contagious.
A dog will continue to shed the virus in its stools for a few days after they recover. We can't be totally accurate because the virus multiplies in the bowel lining and passes into the stools of an infected dog. Once a dog "recovers" the virus ceases to multiply but the virus particles survive in the stools within that dog until they have all been passed. That should be just a few days. So we usually allow a few days after "recovery". The latter meaning that the dog is well, has stopped vomiting and is no longer passing diarrhoea.
The real complication comes with the fact that the virus can survive outside the dog for many months, even up to a year. This means the ground, carpets, feeding
bowls, bedding and anywhere else the patient has vomited or passed diarrhoea. This might even include the dog's own hair. There is the potential for humans to pick this contamination up and transfer it to other dogs. In fact Parvovirus infection is usually picked up by dogs from the ground rather than from direct dog to dog contact. Some pups are infected even when isolated with their own home with their owner transferring the infectionin in on their shoes.
Household bleach is effective in sterilising surfaces but this is of no use with fabrics, etc.
However in a practical sense once a dog has recovered, has been bathed (normal shampoo) and after a few days have passed it should be considered "clean". At least it will pose no greater risk than any other dog might. The main risk to other dogs will be your environment and particulary if an unvaccinated pups up to 4-5 months of age is introduced. I would consider other people handling your dog once itb has recovered to pose minimal risk. Of course they should practice normal hygeine if they then plan to handle an unvaccinated dog.
So it's a bit complicated. Please contact me back if I haven't fully clarified this or if you require further information.
I hope your pup is ok.
Kindest regards, Peter