I had the same question for my vet last year. Until a year or two ago, she says the lepto vacc. had not been available due to the issues you talked about. But, she said the new and improved vacc. currently being given has none of the untoward side effects of the previous one. Like you, I was very worried. She assured me that it was very safe. My dogs are large breeds however, and I did not specifically mention breed size. I think she would have noted any exceptions. However, considering what others here with small breed experience, and the AKC have said, I would look into it further. I have to go to the vet tomorrow, and will ask specifically about this. Lepto was very prevelant here the past few years, with several dog deaths reported, and my kids are always in the woods, ponds, lakes etc. so I felt it very important they get vacc. for this. I'll let you know what my vet says. Sandra