Okay, so I'm really worried about the new puppy I am getting soon. We have been looking after a friend's dog for some months now, and his last vaccination against parvo was in 2011, when he was a puppy. He was due for another vaccination in July this year, but he hasn't had it. Could there be a chance that he could be carrying parvo? He's leaving soon, so he won't be here when the puppy is, but could he still be a danger to her? How can I keep her safe?