Leptospirosis Vaccine Reactions in Dogs

Updated July 19, 2017

Leptospirosis is a serious, potentially fatal disease that affects the liver and kidneys of many animals, including dogs. Due to the severity of the disease, veterinarians often urge their clients to have their dogs vaccinated against leptospirosis. While most dogs will not experience an adverse reaction to the vaccine, it is important to be aware of its potential harmful side effects, and how they could manifest in your dog.


Leptospirosis is caused by an organism called spirochaetes. Many spirochaetes exist in nature, and all but two pose no harm. The ones that do pose harm are Borreia (associated with Lyme disease) and Leptospira, which is responsible for leptospirosis. Among Leptospira, there are several serovars, or strains. Eight of these are known to cause the disease in pets. A dog can pick up the disease by sniffing the urine of infected vermin, wading in or drinking contaminated water or eating infected material. To protect your dog from contracting leptospirosis, it is necessary to have him vaccinated against the disease.

Incidence of Vaccine Reaction

Although most dogs will tolerate the leptospirosis vaccine, there is a higher incidence of adverse reactions following leptospirosis vaccines than any other types of vaccines, according to the American Animal Hospital Association as reported on Dog owners should know what warning signs to look for in their dogs upon administration of the leptospirosis vaccine.

Mild Vaccine Reactions

Following the leptospirosis vaccine, dogs may experience marked pain at the injection site. This reaction can be exhibited in dogs by sensitivity or sometimes even aggression if the site is touched.

Anaphylactic Response

While relatively rare, some dogs will experience an anaphylactic (acutely allergic) response to the leptospirosis vaccine. This reaction is characterised by vomiting, facial swelling, seizures, accelerated heart rate and/or the presence of hives. Additionally, the gums may appear very pale in colour, and the limbs may be cold to the touch. Anaphylaxis is a life-threatening emergency requiring prompt medical attention. If your dog shows signs of anaphylaxis, you should bring him to the vet immediately for care.

Short-lived Immunity

The leptospirosis vaccine only lasts for about a year in most dogs. Occasionally, the vaccine will not protect a dog from leptospirosis, still making him vulnerable to the disease. Given the short-lasting immunity afforded by the vaccine, plus the potential for severe reactions among some dogs, it is wise to assess with your vet whether the benefits of vaccinating your dog outweigh the risks.

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About the Author

Lauren Leatherman has been writing professionally since 2001. She received grants from Breadloaf and the Silver Bay Writers' Institute for her short fiction, and was nominated for inclusion in "Best New American Voices." In 2005, she published the chapbook "How To Lose It" (Hamilton College). Her professional writing encompasses architecture, interior design and health/fitness. Leatherman holds an MFA in fiction from New York University.