Leptospirosis (again! - sorry!)

I found some good threads on this but I have a bit of a dilema. Winston's parents were vaccinated and this included the lepto shot. Winston is having his first shots tommorow and the vet was talking through the vaccinations he gives. This was last week when we were talking. I recently found the "dangers of leto shot" thread and phoned the surgery. He's happy to talk it over with me, he said bring along the thread so he can have a read. It was a bit too sciency for me so I was wondering how many people pass up what seems to be a very neccessary vaccination??!! I really dont know what to do about it! From what I can gather the problem stems from a reaction to the vaccine? If his parents were done I'm assuming the chances of complications are low. The vet lives above the surgery and said he would be happy to be on call any time if I was worried after the shots, but he was very confident that the course they use is very good. I've been with them with my other pets, but as this is a whole new ball park I find myself wavering. Please, any comments?