My vet does not recommend the Lepto for my Yorkies and many a dog has had a bad reaction to this shot.
http://ianrpubs.unl.edu/animaldisease/g417.htm#dogs
Leptospirosis is an infectious disease of animals and man caused by a spiral-shaped organism (spirochete) of the genus Leptospira. The important serotypes recognized in livestock in the United States include Leptospira pomona, L. canicola, L. icterohaemorrhagiae, L. grippotyphosa and L. hardjo. These organisms have a wide host range, including man. Among domestic animals, swine, cattle, dogs, and horses are most frequently affected. Known wildlife hosts include many of the small rodents, raccoons, foxes, opossums, skunks, deer, and moose.
Because of the nature of the disease, it should not be considered a problem of the individual animal but a problem of a population, either a herd or a species within the area. The disease can be controlled by proper management and the correct use of available vaccines.
Method of Spread
Leptospirosis is generally contracted by the direct splashing of urine from infected or carrier animals into the eyes of susceptible animals