The Truth About the Leptospirosis Vaccine: Why Your City Dog May Be Most at Risk
Toby was a 12-pound, apartment-living, belly-scratch-loving little guy. He didn’t hike. He didn’t camp. He didn’t chase wildlife. But he did get seriously ill from something his family never saw coming: Leptospirosis.
At PetMed of Key West Veterinary Clinic in Dubuque, we talk to a lot of pet parents who assume the leptospirosis vaccine is only for large, outdoor dogs. But the truth is: it’s often our smallest, most urban pets who are most at risk.
What Is Leptospirosis?
Leptospirosis is a bacterial infection spread through the urine of infected animals — especially wildlife and rodents. Dogs can become infected by drinking or walking through contaminated puddles, standing water, or even damp grass where an infected animal has been. Once inside the body, leptospirosis can damage the kidneys, liver, and other vital organs. It can lead to lifelong health complications — or worse.
And it’s not just dangerous to dogs — it’s zoonotic, meaning it can spread to people too.
How the Vaccine Protects
At PetMed of Key West, we use a leptospirosis vaccine that protects against multiple strains of the bacteria — not just one. This is critical, because different strains circulate in different environments, and we want your dog protected no matter where they roam… or sniff.
But I Heard the Vaccine Causes Reactions…
Yes, it’s true: the lepto vaccine can cause more reactions than other common vaccines — especially in small breed dogs. But it’s important to understand the full picture.
Most reactions are mild and short-lived: slight soreness, tiredness, or a low-grade fever. And here’s the twist — the same small dogs who are most prone to reactions are also the ones most likely to get severely ill if they contract leptospirosis. That’s why we still strongly recommend the vaccine for small dogs, especially those who live in town or in neighborhoods with known rodent populations.
Lepto Isn’t Just a Country Dog Problem
It used to be thought of as a “big dog, outdoor life” issue — the kind of thing you worry about if your Labrador is jumping in lakes or your hound is hunting in the woods. But that old thinking is dangerously outdated.
Today, Leptospirosis is a growing threat in urban and suburban areas, largely due to the increase in rodent populations. Rats, mice, raccoons, and skunks are common in cities — and they’re the most likely to spread the disease. Your dog doesn’t need to leave the backyard, the sidewalk, or the neighborhood park to be exposed.
When and How Often to Vaccinate
At PetMed, we recommend starting the leptospirosis vaccine as part of your puppy’s routine series, or at your adult dog’s next annual visit if they haven’t had it before:
- Initial series: Two vaccines given 3–4 weeks apart.
- Annual booster: Once yearly after the initial series for ongoing protection.
We’ll help determine the right timing and make sure it’s paired safely with your dog’s other core vaccines.
The Takeaway: A Small Sore Leg Beats Kidney Failure
We understand concerns about vaccine reactions — and we always take precautions to minimize them. But when weighed against the risk of life-threatening illness, a day of post-vaccine soreness is a small price to pay. Especially when it could be what saves your pet’s life.
If your dog hasn’t been vaccinated for leptospirosis — or if you’re not sure — give us a call at PetMed of Key West Veterinary Clinic in Dubuque. We’ll talk you through the pros and cons and help create a vaccination plan that gives your pet the protection they need.