I did have a dog react.. she looked like a manatee but she was still with her breeder, an awesome vet tech, so not a biggie. But I began doing research and decided that most logical was if it is in your area, give it. If it isn't common, more vaccines does not – imho -- equal better.
The my daughter was in Costa Rica doing volunteer work, they took a break white water rafting, got dumped into the water and she and 2 other kids came home with lepto. SHE was lucky, as she had a sinus infection (she nearly drowned btw), so we put her on steroids and antibiotics immediately for that. The doctors think she had a milder case thanks to it. The other two, boys, both ended up hospitalized and were in pretty bad shape. One parent (lots of financial resources) had called in a tropical disease doctor who identified it pretty fast when the hospital didn't -- guiding the testing for Leora and the other guy. It was a bloody nightmare with testing forever .
So, I have experience of the horrible kind with it. Guess what, I still say research and if it's not in your area, consider not doing it. If it IS a problem near you, not worth risking it. .. get the vaccine and watch for problems.