The specialist vet who treated Henry said that puppies can pick up viruses from
vaccinated dogs. He also said that socialisation is very important, and that we shouldn't have done anything differently. He also pointed out that some vaccines are less effective than others, and some dogs respond better than others as well. On the whole, I suspect we were just very, very unlucky.

If I ever have another pup, I'm not sure how I would feel about them mixing with ANY other dog before all their vacs. But obviously after what we've been through, I would be an
extremely paranoid puppy Mummy.

But as someone else said, if you have a multi dog household, then your pup is automatically going to be mixing with other dogs anyway.