In 1962 we had 2 puppies and at that time people did not have their dogs injected like they do now, we never had either of ours injected during the 12 years we had them and they were never ill. I remember at that time you still had to have a licence. I used to pay for them out of my pocket money.
When we lived in Hampshire we had a Yorkie and our vet said you did not have to have the booster done exactly every 12 months as they would be covered for up to 15 months without a problem and thats what we did with Pepper and she lived to 16 years.
We now have Holly and she is just due her first yearly booster, as there is more Parvo about now and especially, I am told in this area I will be getting it done soon.