- August 18, 2026
- Dogs, Pet Health & Wellness
Why the leptospirosis vaccine is now core for every dog
The leptospirosis vaccine for dogs is now a core vaccine, which means AAHA recommends it for every dog, not only farm and hunting dogs. If someone told you years ago to skip it for a dog who lives in a Parma house and walks the same few blocks, that advice made sense then. The guideline behind it changed in 2024. Here is what changed, why, and what it means for your dog.
Key takeaways
- In 2024, AAHA updated its canine vaccination guidelines so that leptospirosis is a core vaccine for all dogs, not only dogs with a farm or hunting lifestyle.
- Leptospirosis spreads through the urine of infected animals, including wildlife that lives in suburban yards. It can injure the kidneys and liver, and people can catch it too.
- Lyme disease vaccine is still a risk-based choice, not a core one. The two are different decisions, even though a new combined shot can deliver both at once.
- A first-time course is two doses a few weeks apart, then a yearly booster. AAHA reports reactions to current leptospirosis vaccines as rare, and your veterinarian can tailor the plan for your dog.
Why the leptospirosis vaccine for dogs became core
AAHA published its canine vaccination guidelines in August 2022. In 2024 it updated them to include leptospirosis, often shortened to “lepto,” as a recommended core vaccine for all dogs.
Core means recommended for every dog, regardless of lifestyle. AAHA’s current core list is distemper, adenovirus, parvovirus, leptospirosis and rabies, with parainfluenza listed alongside them as a plus-or-minus. That is why lepto can now appear on an estimate for a dog whose owner was once told it was optional.
AAHA’s own magazine calls the change a significant change in veterinary medicine. It also notes a 2023 consensus statement from the American College of Veterinary Internal Medicine recommending the vaccine for all dogs over 12 weeks of age. The same article reports that in early 2020 only 63.4% of dogs current on their core vaccines had received a leptospirosis vaccine in the previous 14 months.
Lyme disease is a different story. AAHA keeps the Lyme vaccine in its risk-based group, next to Bordetella, canine influenza and rattlesnake toxoid. “Core” means every dog gets it. “Risk-based” means we talk about where your dog goes and what they encounter, and then decide.
We have chosen to be accredited by the American Animal Hospital Association (AAHA), the same organization that writes these guidelines. Our page on which vaccines your dog should be current on covers the full picture.
Leptospirosis in dogs: what the infection does
Leptospirosis is an infection caused by Leptospira bacteria. According to the AVMA, these bacteria live in soil and water worldwide, and dogs, people, livestock and wildlife can all be infected.
The illness varies a great deal. Some infected dogs show no signs, some recover on their own, and others become seriously ill. The early signs are vague: less interest in food, vomiting, tiredness, belly pain, diarrhea, and drinking or urinating more than usual. Some dogs are stiff or have yellow-tinted skin or gums. The AVMA notes the disease can progress to kidney or liver failure, and sometimes to serious lung disease or bleeding problems.
Treatment is antibiotics and supportive care, and the most severe cases may need intensive care, including dialysis. The chance of recovery is good when treatment starts early, the AVMA says, but lasting kidney or liver damage is still possible. One more fact matters later: infected dogs can look healthy and still pass the bacteria in their urine.
Call us the same day if your dog shows these signs: vomiting that continues, refusing food, unusual tiredness, belly pain, a sudden change in how much your dog drinks or urinates, yellow gums or skin, or blood in the vomit, urine or stool. These signs fit many illnesses, which is why we want to examine the dog rather than guess. Call 440.845.7141, or see our urgent care page for what to do next.
Where dogs pick up leptospirosis, and why your household has a stake
The old picture was a large dog from a rural property. AAHA says this is “no longer true.” Small-breed dogs are frequently infected, and AAHA suggests the reason may be urban and suburban exposure to wildlife that carry the bacteria, including rodents.
AAHA lists these risk factors:
- Spending any time outdoors, whether the setting is urban, suburban or rural.
- Exposure to rodents.
- Time in kennels or dog daycares.
The AVMA adds slow-moving or standing water, wild animals even in the backyard, and contact with other dogs at places such as dog parks. It names the Midwest among the hotspots for infection in dogs, and says all dogs are at risk regardless of age, breed, lifestyle or location.
Cornell’s wildlife health program lists wildlife that can act as reservoirs: raccoons, skunks, squirrels and opossums among them. None of those animals needs a farm.
The bacteria leave an infected animal in its urine, and the AVMA says they can survive for weeks to months in urine-soaked soil. Think of ordinary spots: a puddle by the downspout after heavy rain, the edge of a retention pond, the ground under a bird feeder. A dog can be exposed by drinking there, or by getting that water or soil on the nose, in the eyes or into a scrape.
What it means for the people in your house
Leptospirosis is a zoonosis, which means it can affect people as well as animals. The CDC describes the same route in people: contact with water or soil that contains urine from infected animals. It lists gardening, yardwork and veterinary clinic work among the activities that raise risk, and says it is rare for one person to pass it to another.
The link between dogs and people is indirect. AAHA says there is little evidence of direct infection from dogs to people, but a dog that moves between contaminated ground and your living room can connect the two. AAHA adds that newer vaccines have been shown to dramatically reduce or prevent shedding of the bacteria in urine, which may protect people indirectly.
The AVMA offers simple household habits: wash your hands after handling a sick dog, clean up urine promptly with a household disinfectant while wearing gloves, and encourage your dog to urinate away from standing water. If anyone at home is pregnant or has a weakened immune system, it advises asking their physician.
The dog vaccine schedule for lepto: first course and booster
This describes the published guideline, not a plan for your dog. Your veterinarian sets the actual schedule at an exam.
A first-time course
AAHA recommends the four-serovar leptospirosis vaccine, which covers four strains of the bacteria that matter in North America. For a first course, AAHA’s table lists two doses given two to four weeks apart. The AVMA describes the two doses as spaced 4 weeks apart.
Puppies start at 12 weeks of age or later. An adult who has never had the vaccine also gets the two-dose course, regardless of age.
A booster
After the first course, AAHA lists one dose within a year of the last dose in the series, then boosters every year. The guideline puts the length of protection at roughly 12 to 18 months. That is shorter than the distemper, adenovirus and parvovirus vaccines, which AAHA’s table spaces three years apart.
If the last dose was a long time ago, whether a booster is enough or the course should be repeated is a decision for the examining veterinarian.
The new combined lepto and Lyme option
On June 15, 2026, Elanco announced USDA approval of TruCan Ultra Lyme-L4. AAHA’s magazine describes it as the first half-milliliter combination leptospirosis and Lyme vaccine for dogs. Its practical effect is one injection instead of two for a dog who needs both.
That is useful for a dog with real tick exposure. It does not change the core and risk-based distinction: a combined shot does not make Lyme vaccine core, and not every dog needs Lyme protection. Ask us whether your dog is a candidate.
Leptospirosis vaccine side effects: the honest part
If someone told you to skip the leptospirosis vaccine, a reputation for reactions was probably the reason, and that reputation had a basis. AAHA’s guideline says veterinarians have historically been concerned about adverse reactions to these vaccines.
Here is what AAHA says has changed. Vaccine formulations have been altered to reduce the likelihood of reactions. Based on available information, AAHA describes adverse reactions as rare, at fewer than 53 per 10,000 doses, which is about half of one percent. Most are minor. Serious allergic reactions were reported no more often with leptospirosis vaccines than with other vaccine antigens. The AVMA puts it simply: leptospirosis vaccines are no more likely to cause side effects than other common vaccines.
Rare is not never. Adverse reactions of any type are more likely in smaller and younger dogs. For that reason AAHA suggests the first dose at or after 12 weeks of age. It also suggests giving fewer different vaccines at a single visit. AAHA’s leptospirosis chapter sets all of this out.
If your dog has ever reacted to a vaccine, tell us before any shot, and we will plan around it. The AVMA’s vaccination page says serious allergic reactions are rare but can be life-threatening, and that they can start within a few minutes to hours of the shot. Seek veterinary care immediately for swelling around the face, hives, persistent vomiting, difficulty breathing or collapse.
The trade is a small, mostly mild risk of a reaction against a disease that can damage the kidneys and liver. Your dog’s size, age and history tilt that balance, so the conversation belongs in the exam room.
Before your next appointment
You can do this in your kitchen in about ten minutes.
- Find your dog’s vaccine record and look for the leptospirosis line. Note the date of the last dose, or note that there is none.
- Write down where your dog spends time: the yard, walks near water or a retention pond, dog parks, daycare, boarding or travel.
- Note any wildlife or rodents you have seen near your home, and whether your dog drinks from puddles.
- Write down any past reaction to a vaccine, however mild.
- Ask whether your dog needs Lyme protection too, and whether a combined shot makes sense.
- Tell us about upcoming boarding, trips or daycare, because they can change the timing.
Leptospirosis vaccine questions owners ask
Is the leptospirosis vaccine necessary for an indoor dog?
AAHA now recommends it for all dogs, and the AVMA says all dogs are at risk regardless of lifestyle. Even a mostly indoor dog goes outside to relieve themselves, and the bacteria can persist in soil. If your dog spends very little time outdoors, ask your veterinarian whether that changes the plan.
Can my dog get lepto in the city?
Yes. AAHA says the old idea that lepto affects mainly rural, large-breed dogs is no longer true, and it names urban and suburban exposure to wildlife, including rodents, as a possible reason small dogs are frequently infected. Rats, raccoons and other wildlife live in cities and suburbs too.
How often does my dog need the leptospirosis vaccine?
AAHA’s schedule is a first course of two doses a few weeks apart, then a booster within a year, then yearly after that. Protection from these vaccines lasts roughly 12 to 18 months, which is why the booster is annual. Your veterinarian confirms the plan for your dog at the exam.
My dog had a reaction to a vaccine before. Should I skip lepto?
Not on your own. Tell your veterinarian exactly what happened and with which vaccine. AAHA notes that reactions of any type are more likely in smaller and younger dogs, and that giving fewer different vaccines at one visit can help. The right decision depends on the type of reaction and your dog’s exposure, so it is made at an appointment and not at home.
Does the Lyme vaccine protect against leptospirosis too?
No. They are separate diseases with separate vaccines. Lyme comes from tick bites and is risk-based, while leptospirosis comes from contact with infected urine and is core. A combined product now exists that delivers both in one injection, but a dog still receives it only if the veterinarian judges that both protections are appropriate.
Talk with us in Parma
If you are not sure where your dog stands, the answer is usually a quick look at the record. We plan vaccinations one dog at a time at our wellness exams, and our post on why we suggest an exam twice a year explains why the exam itself is the most important part of the visit.
We are at 6270 State Road in Parma. The hospital is open Monday through Friday from 7:30 a.m. to 5:30 p.m. and is closed Saturday and Sunday. Call 440.845.7141, or request a visit with one of our veterinarians and bring the vaccine record with you.
