Side Effects of Leptospirosis Vaccine for Dogs

By Naomi Millburn

Leptospirosis is a potentially life-threatening disease brought on by exposure to a bacteria called Leptospira, which lurks in infected urine and contaminated water or soil. Although the leptospirosis vaccine does not protect against all strains, it is still recommended for dogs at risk. Possible side effects of the leptospirosis vaccine for dogs include appetite loss and lack of energy.

Leptospirosis Vaccine Basics

The leptospirosis vaccine is a non-core vaccine, so it's not required for all dogs. Veterinarians generally decide whether or not dogs are good candidates for the vaccine by assessing their specific risk levels. Young puppies generally are given these vaccines when they're 12 weeks in age and then again between two and four weeks later. Mature dogs and puppies who are at least four months in age who have never been vaccinated against leptospirosis are usually given two doses of the vaccine spaced apart between two and four weeks. Dogs who have relatively high risks are advised to get revaccinated on a yearly basis. Those who have severely high risks, however, are advised to get leptospirosis vaccines in intervals of between six and nine months.

The leptospirosis vaccine can defend dogs from getting infected, but not in all cases. Many kinds of leptospires exist, and the leptospirosis vaccine doesn't offer immunity from all of them.

Possible Side Effects and Reactions

Side effects of the leptospirosis vaccine can appear in some dogs. They include reduced energy and appetite loss. Some dogs get skin rashes that are particularly obvious on parts of their body that lack hair, too. Dogs occasionally experience shock responses soon after getting these vaccines. Toy breeds, for example, may be vulnerable to anaphylactic shock reactions caused by these vaccines. Anaphylaxis is an urgent condition that happens when an animal has a negative response to a specific allergen. Severe cases of anaphylaxis can often be life-threatening. Potential signs of anaphylactic shock in dogs include:

  • Vomiting
  • Diarrhea
  • Urination
  • Passing stools
  • Loss of energy
  • Weakness
  • Itching
  • Salivation
  • Problems breathing
  • Heightened heart rate
  • Coma
  • Seizures
  • Death

If you notice any potential side effects or adverse reactions to this vaccine in your pet, notify your veterinarian of the matter promptly.

Risk Factors

This bacterial disease is particularly prevalent in locations that have wet and warm weather. If your dog resides in a rural location that has an abundance of wildlife, he probably has a higher risk of contracting leptospirosis. Dogs frequently get infected with leptospirosis by consuming water that has been infected by the bacteria, whether from outdoor watering stations, lakes, rivers, streams or ground water. If your dog spends a lot of time in or around water outdoors, particularly in a warm and damp climate, then he may be at high risk.

Protect Yourself

Although the odds of your dog passing leptospirosis on to you or to any other person are slim, they're not nonexistent. If your dog has this bacterial disease, keep his urine away from your bare skin. Use rubber gloves when you clean up any spots your dog urinated on, too. Disinfect any locations that may contain his urine.

Never assume that a dog who is vaccinated against leptospirosis can't spread the disease to a human or to another animal. Dogs who are immunized against leptospirosis continue to shed the bacteria in their urine. As a result, they're still capable of passing it on to others.


Since dogs from toy breeds are susceptible to anaphylactic shock reactions caused by leptospirosis vaccines, the vaccines should only be given to those who have high risk of contact with the bacteria. If you own a toy breed, speak to your veterinarian about his risk of contact with Leptospira.