Hi, I agree with others who have said to go back to your vet, I have heard of this happening before though. I was once told by an ex RSPCA vet no less that after the first annual booster (that's a year after the puppy ones) that a dog doesn't need any more as this one gives immunity for life, obviously if you put your dog in kennels when you go on holiday then you have to prove that injections have been done, my dogs only get an annual jab against Leptospirosis as I live on a farm with the inevitable rat population, and rats are carriers, my vet has never suggested that I am doing the wrong thing., makes you wonder?