The Lyme vaccine is controversial. According to Dr. Meryl Littman, Associate Professor of Medicine at the Ryan Veterinary Hospital of the University of Pennsylvania, over 95% of dogs that are exposed to the Lyme organism do not develop symptoms or have non-serious symptoms that resolve within a week on their own. Those dogs that do develop Lyme arthritis (less than 5% of those that are exposed), are easily treated with safe and inexpensive antibiotics. A less common but more serious form of Lyme disease that tends to affect Labrador Retrievers, Golden Retrievers, and Shelties is probably due to an immune-mediated condition because of genetic risk, and vaccination might actually increase the risk of this problem if the dog is later exposed. (Penn Annual Conference 2006)
Leptospirosis is a growing concern in dogs…or at least a growing market for the vaccines. There are 3 important issues related to this vaccine. First, there are 4 strains of Leptospirosis that are most likely to infect dogs. A vaccine that only protects against 2 strains might be missing the one that could infect your dog. Duration of immunity, or how long the vaccine lasts. For most of the leptospirosis vaccines, only a maximum of 3 months of immunity has been shown. Tests by one company producing only a 2-way vaccine have demonstrated one year of immunity.
Protection by the vaccine. Leptospirosis is of concern because it is a disease that can be transmitted to humans. Ideally, the vaccine should prevent the dog from getting the leptospirosis organism. However, studies have shown that dogs still "shed" the organism in their urine if they are infected, even if they have been vaccinated. This could pose a false sense of security to dog owners and actually increase their risk of contracting the disease.
Safety of the vaccine. All of the vaccines have been shown to cause a hypersensitivity reaction that can last up to 4 years. (Personal communication with Dr. Ronald Schultz, School of Veterinary Medicine University of Wisconsin-Madison, October 2005) In our experience, this disease is extremely rare in our area, and is found mostly in dogs with severely immunosuppressed systems. We have not diagnosed a case in years.