Leptospirosis is a disease found in many animals including dogs. Leptospirosis is a bacterial disease and becomes a source of many other harmful to deadly conditions in the host. The sole source of leptospira bacteria is the wild rodents.

Dogs become infected with the bacteria when their conjunctiva or mucus membrane gets exposed to the infectious agent. Leptospirosis is most common in dogs. But the good news is that vaccination against leptospirosis is available. But before administering any vaccination in your dogs, it is crucial to know its benefits and side effects. So, in the following article, we will see what are the pros, and cons of the leptospirosis vaccine.

The leptospirosis vaccine has many benefits. But like all vaccines, the leptospirosis vaccine does not prevent the disease. In fact, it creates a specific number of antibodies that make the disease much milder if infection occurs. There are also several side effects of the leptospirosis vaccine, but in most cases, they are mild. The most common side effects of the leptospirosis vaccine are lethargy, mild fever, and loss of appetite. While the acute side effects of the vaccine include diarrhea, allergy vomiting, and collapse.

If we see in detail, the leptospirosis vaccine has more benefits or pros than cons. Before discussing the pros and cons of the leptospirosis vaccine, let’s discuss a bit about leptospirosis infection in dogs. It will help us to better understand how crucial the leptospirosis vaccine is? Let’s discuss what leptospirosis is and why it is dangerous for dogs?

What is Leptospirosis in dogs?

Leptospirosis is a bacterial disease. It affects animals and humans. Bacteria of the genus leptospira cause the disease. Leptospirosis causes a wide range of symptoms in dogs and all the other hosts.

Leptospirosis spread through the urine of infected animals. The urine of the infected animal stays in the water and soil and can survive there for a long time. Different kinds of domestic and wild animals carry the leptospira genus. But wild species, specifically the raccoons, are the most important carriers of the infection.

dog in water

You must be wondering why we specifically paying a head-on on leptospirosis infection of dogs? As we have talked about leptospirosis diseases and vaccines previously, that is because it is a zoonotic disease, it can spread from your dogs to you. So, it is crucial to keep an eye on your dog and get your dog vaccinated against leptospirosis infection.

Another substantial thing about leptospirosis infection is that it might be non-symptomatic in dogs, but it can cause severe disease in humans. Leptospirosis infection can even cause acute ailments in humans. So the vaccine is the best solution to avoid this tantrum.

If leptospirosis infection continues to proceed in the body without medication and vaccine, it can lead to meningitis, kidney infection, liver failure, respiratory distress, and can even cause death.

Now let’s discuss the vaccine for leptospirosis.

Leptospirosis Vaccine

Although leptospirosis could be a deadly disease, you can prevent it by the vaccine. Vaccine against leptospirosis is available around the globe, and it is doing very well in immunizing dogs.

So do consider administering the leptospirosis vaccine to your four-footed friend. American Animal Hospital Association has regarded the leptospirosis vaccine as the non-core vaccine. Non-core vaccines mean you should vaccinate your pet against bacteria if there is a chance of exposure to bacteria.

Once administered, the leptospirosis vaccine can’t guarantee lifetime immunization against the leptospira genus. Instead, booster shots are administered to ensure long-lasting immunity. Also, we have described that the current leptospirosis vaccine is not effective against all spores of the bacteria. The current vaccine of leptospirosis is only effective against 6-7 spores of leptospira. And these 6-7 spores are the most deadly. All other spores of the leptospira are either non-diseases causing or cause only a mild illness in dogs.

It was all that you need to know about the leptospira and leptospirosis vaccine. Now let’s see, what are the pros and cons of the leptospirosis vaccine?

What are the Pros of Leptospirosis Vaccine?

In general pros of a thing are its plus points that advocate us to use a particular thing, and cons are the negative point of that thing. The decision of vaccine administration is done based on its pros and cons. For example, if the pros of the leptospirosis vaccine are strong enough to prevent the disease, and cons of the vaccine are mild. Then veterinarians will ask you to go for vaccination, and vaccination will be called safe.

Leptospirosis has several pros and a few cons. We will discuss both in detail. Let’s begin with the pros of the leptospirosis vaccine.

Pros of leptospirosis vaccine

There is a long list of the pros of the leptospirosis vaccine:

  • It protects your dog against the potentially harmful strain of leptospira strain.
  • It is an FDA-approved vaccine. and according to the reports of the Food and Drug Administration, the leptospirosis vaccine is safe.
  • Leptospirosis vaccine not only saves the vaccinated individual but also saves the surrounding individuals well.
  • It provides immunization to your dog for the future.
  • It prevents all the symptoms of leptospirosis disease like:
    • High fever
    • Headache
    • Chills
    • Red eyes
    • Abdominal pain
    • Diarrhea
    • Rash
    • Muscle aches
    • Vomiting
    • Jaundice

In nutshell, the vaccine can protect your dog from the various effects of leptospira bacteria.

As you know, no vaccine is 100% effective and almost all vaccines have side effects. Same, in the case of leptospirosis. The leptospirosis vaccine also has some cons and side effects, yet it is regarded as one of the safest vaccines for dogs.

The side effects of the vaccine are either short-lived or mild. A very few long-term side effects are present.

The side effects of leptospirosis are usually due to a number of other causes. Like if you vaccinate your dog simultaneously against leptospirosis and another disease. Then there are more chances of side effects appearing. Also, the side effects of the leptospirosis vaccine are more prominent in dogs of young age and in immunocompromised dogs.

Let’s discuss all the cons or side effects of the leptospirosis vaccine in detail.

What are the Cons of Leptospirosis Vaccine?

Leptospirosis vaccines consist of different components, and all the components can affect differently. A certain component might cause a reaction in an individual while remaining non-toxic to others. That is why different dogs show different side effects of the vaccine. The earlier form of leptospirosis vaccine was risky and has a number of side effects.

The debut leptospirosis vaccine was even considered a deadly vaccine. But by the time leptospirosis vaccines improved a lot. By various improvements, the leptospirosis vaccine has a minimal side effect now. As we explained above, the cons or the side effects of the leptospirosis vaccine are short-lived and mild. So let’s see the side effects of the leptospirosis vaccine.

The initial side effects of the leptospirosis vaccine are the same as many vaccines. Like:

  • Mild swelling at the injection site
  • Mild fever and tiredness

The mentioned effects are not the side effect of the leptospirosis vaccine; they are just common outcomes of almost every vaccine. Another usual outcome of the vaccine is the feeling of discomfort.

The advanced cons of the leptospirosis vaccine are:

  • Dyspnea or lack of proper breath, the reason for this is unknown, but owners have reported that their dogs have gone through mild dyspnea after the vaccine shot
  • Vomiting and diarrhea are also common side effects of the vaccine. Often a problem with digestion is also reported.
  • Allergic reaction is also a frequent side effect of the leptospirosis vaccine. If you observe any sign of urticaria in dogs, contact the veterinarian as soon as possible.
  • Along with general depression, dogs often feel hypertension immediately after the vaccination shot. It is due to the weakened infectious agent that is introduced in the dog’s body through injection.
  • Leptospirosis vaccine can also cause nausea, lack of attention, and laziness in the dog. But these conditions become better after 1-2 days.

The mentioned side effects of the vaccine are rare and often appeared in young dogs or immune-compromised ones.

Until now, no report of death is associated with the leptospirosis vaccine (with the modern version.)

It is easy to reverse the side effects of the vaccine. Important point is to keep the dog under observation for two to three days after the vaccination. If you see any side effects, seek veterinarian help as soon as possible.


By seeing the number, you might think that the cons of the leptospirosis vaccine are more than the pros, but, the fact is that the leptospirosis vaccine is effective to prevent the disease. The cons or side effects of the vaccine are very mild in most of the conditions and could be treated very easily.

Leptospirosis is a devastating disease, and also it is zoonotic. So, if your dog is at risk of infection, then you should consider administering a vaccine to your dog.

Veterinarians suggest a leptospirosis vaccine for dogs above 2-3 months of age. And also, it is recommended not to administer the leptospirosis vaccine with any other vaccine. If a combination of vaccines is administered then several side effects could appear.