Home Leptospirosis Lepto Vaccine

Leptospirosis Vaccine for Dogs

By the Dog Health Handbook team · Updated · Fact-checked against current veterinary references (see sources)

Key takeaways

  • The vaccine covers the four most common lepto types in North America.
  • AAHA lists it as core for all dogs since 2024.
  • Two doses 3 to 4 weeks apart, from 12 weeks of age, then yearly boosters.
  • Reactions are uncommon and no more frequent than with other vaccines.
  • Small and city dogs need it too.

Table of Contents

Research Does my dog need it? Schedule Side effects Small breeds Vaccinated dogs Cost FAQ Sources

Leptospirosis Quicklinks

Leptospirosis Lepto Vaccine Vaccination Schedule DHPP Vaccine Kidney Disease Liver Disease

The leptospirosis vaccine protects dogs against the four types (serovars) of Leptospira bacteria most common in North America: Canicola, Icterohaemorrhagiae, Grippotyphosa and Pomona.1,2 Since a 2024 update, the American Animal Hospital Association (AAHA) lists it as a core vaccine for all dogs, and the 2023 ACVIM consensus recommends it yearly for every dog from 12 weeks of age, regardless of breed.3,4,5 Puppies and unvaccinated adults need two initial doses, usually 3 to 4 weeks apart, then a booster every year. Protection lasts at least 12 months.5,6,1 Large studies show reactions are uncommon and no more frequent than with other routine vaccines.7,5 Vaccinated dogs can occasionally still get lepto from other serovars, but serious cases mostly occur in unvaccinated dogs.5,8

Call your vet after a vaccine if your dog has:

  • Facial swelling, hives, itching, vomiting, trouble breathing or collapse, which can be an allergic reaction. Trouble breathing or collapse is an emergency, so go to the nearest vet right away. Most reactions to lepto vaccines are allergic-type.9,10

If your dog has reacted before, tell your vet. They may give fewer vaccines at one visit.11,2

What the Research and Guidelines Say

  • Low reaction rate. A 2023 study of more than 4.6 million US dogs found 21.4 reactions per 10,000 lepto vaccine doses, compared with 24.6 for distemper-parvo combination vaccines and 24.8 for rabies. Lepto vaccines were more often linked to mild reactions, and rabies and distemper-parvo vaccines to more serious ones.12,7
  • Very rare serious events. The UK regulator reported in 2026 fewer than 4 reported adverse events per 10,000 dogs given four-serovar vaccines, and fewer than 1 per 10,000 involving death.9
  • Now core. AAHA moved the vaccine from non-core to core in 2024, and a guideline task force member said "the real risk factor" is whether a dog is vaccinated.4
  • Small dogs need it too. ACVIM's lead author writes that vaccination is "strongly recommended even for small-breed dogs" in urban areas.13

Does My Dog Need the Lepto Vaccine?

Major US guidelines now say yes for almost all dogs. AAHA calls it core, ACVIM recommends it annually for all dogs from 12 weeks, and WSAVA advises it as core wherever leptospirosis is common.3,5,14 Lepto was once thought of as a disease of large rural dogs, but it's now seen in small and urban dogs, and "any dog that goes outdoors, whether in an urban or a rural setting, can be exposed."2,4 ACVIM says vaccination should be required for boarding and daycare.4 See leptospirosis in dogs.

Lepto Vaccine Schedule

  • Puppies: the first dose at 12 weeks or older, and a second dose 3 to 4 weeks later, often at the last two puppy visits5,6,4
  • Adult dogs never vaccinated: two doses, about 4 weeks apart5,15
  • Boosters: every year. Protection lasts at least 12 months, and AAHA says up to 18 months depending on the serovar.5,2,1

See our dog vaccination schedule.

Side Effects

Most reactions are mild to moderate.7,11 Serious allergic reactions are rare.9,5 Reaction risk for all vaccines is higher in small dogs, in certain breeds such as French Bulldogs, Dachshunds and Boston Terriers, and when several vaccines are given at once.7,16 Practical steps that may reduce risk include:

  • Spreading vaccines over separate visits for dogs at higher risk11,2
  • Letting some vaccines reach room temperature before injection2,9
  • Watching your dog for at least 30 minutes after vaccination10

Small Breeds and the Lepto Vaccine Myth

Some owners and breeders avoid the lepto vaccine because of concerns about reactions in toy breeds, and a 2022 UK study found toy breeds were less likely to receive it.17 Newer data show lepto vaccines are not riskier than other vaccines, and small-breed dogs in cities are among those getting leptospirosis.7,5,13 For small dogs with a history of reactions, splitting vaccines into separate visits is usually a better option than skipping lepto.11,4

Can Vaccinated Dogs Still Get Lepto?

Yes, but it's uncommon. There are more than 300 disease-causing serovars, and the vaccine covers only the four most common in North America.13,5 Vaccination also reduces kidney infection and shedding in urine.1,2 Dogs that have had lepto should still be vaccinated.18

The vaccine can cause positive antibody tests, but not a positive PCR test, so tell your vet when your dog was last vaccinated if lepto is suspected.2,13

Cost

Lemonade Pet Insurance reports an average of about $52 per dose in the US, ranging from about $30 to $80 by state, based on 2025 to 2026 invoices.19

Frequently Asked Questions

Is the lepto vaccine really necessary?

Major guidelines now recommend it for all dogs, including small and city dogs.

How often do dogs need the lepto vaccine?

Every year, after two initial doses.

Is lepto part of DHPP?

No, but it's often combined. DHLPP includes leptospirosis. See the DHPP vaccine.

Is the lepto vaccine safe for small dogs?

Yes, for most. Reactions are uncommon. Small dogs with past reactions can have vaccines spread out.

Why do some breeders avoid the lepto vaccine?

Mainly older concerns about reactions, which newer large studies haven't supported.

Ask Our Team a Question

Help Others by Sharing Your Dog Story or Question!

Have a Question, Request or Want to Share a Story that could help others? Our team will answer questions for free!

Please include information such as your dog's medical history, age, sex, breed, symptoms, diet, changes in behavior and medications. Providing pictures by uploading them below can also be of help.

We will do our best to get back to you quickly (it depends on how many questions we receive each day). If you do require an immediate response we suggest using this online dog veterinary service that is available now.

[ ? ]

Upload 1-4 Pictures or Graphics (optional)[ ? ]

 

Click here to upload more images (optional)

Author Information (optional)

To receive credit as the author, enter your information below.

(first or full name)

(e.g., City, State, Country)

Submit Your Contribution

  •  submission guidelines.


(You can preview and edit on the next page)

Sources and further reading

This article was rewritten and fact-checked on October 23, 2026 against current veterinary references and specialist guidelines:

  1. Lunn KF. Leptospirosis in Dogs. MSD Veterinary Manual, updated July 2026.
  2. American Animal Hospital Association. Key Vaccination: Leptospirosis. 2022 AAHA Canine Vaccination Guidelines, 2022.
  3. American Animal Hospital Association. 2022 AAHA Canine Vaccination Guidelines (updated 2024). Journal of the American Animal Hospital Association, 2022.
  4. American Animal Hospital Association. Update: AAHA guidelines designate Leptospirosis vaccine as core. AAHA NEWStat, January 2025.
  5. Sykes JE, Francey T, Schuller S, Stoddard RA, Cowgill LD, Moore GE. Updated ACVIM consensus statement on leptospirosis in dogs. Journal of Veterinary Internal Medicine, 2023.
  6. Cornell Richard P. Riney Canine Health Center. Canine leptospirosis. Cornell University College of Veterinary Medicine, updated November 2024.
  7. Weese S. More on Canine Vaccine Adverse Events. Worms & Germs Blog, November 2023.
  8. New York City Department of Health and Mental Hygiene. 2025 Veterinary Advisory #10: Summary of 2024 Canine Leptospirosis Surveillance in New York City. NYC Health, December 2025.
  9. Veterinary Medicines Directorate. VMD reaffirms safety of Leptospira vaccines in dogs. GOV.UK, March 2026.
  10. Harrus S, Waner T. Review: Canine Vaccination Guidelines in Israel. Israel Journal of Veterinary Medicine, 2020 (IVIS).
  11. Hanson JM. Understanding Risk for Vaccine Adverse Effects in Dogs. Clinician's Brief, Spring 2024.
  12. Moore GE, Morrison J, Saito EK, Spofford N, Yang M. Breed, smaller weight, and multiple injections are associated with increased adverse event reports within three days following canine vaccine administration. Journal of the American Veterinary Medical Association, 2023.
  13. Sykes JE. An Update on the Diagnosis and Management of Leptospirosis. Today's Veterinary Practice, March/April 2025.
  14. WSAVA Vaccination Guidelines Group (Squires RA, et al.). 2024 Guidelines for the Vaccination of Dogs and Cats. World Small Animal Veterinary Association, 2024.
  15. American Veterinary Medical Association. Leptospirosis in Dogs (pet owner brochure). AVMA, 2025.
  16. Moore GE. Vaccine safety (conference notes). Auburn University small animal conference, 2023.
  17. Taylor C, O'Neill DG, Catchpole B, Brodbelt DC. Leptospirosis vaccination in dogs attending UK primary care practices: vaccine uptake and factors associated with administration. BMC Veterinary Research, 2022.
  18. Washington State Department of Health. Canine leptospirosis. Washington State Department of Health.
  19. Lemonade Pet Insurance. How Much Does the Leptospirosis Vaccine Cost? Lemonade, updated October 2026.

About this article

Last updated : written using the 2022 AAHA vaccination guidelines (2024 update), the 2023 ACVIM leptospirosis consensus, WSAVA 2024 guidelines, UK regulator data and 2022 to 2025 vaccine safety research, plus International Veterinary Information Service (IVIS) proceedings and research published 2022 to 2026.

This page is for general information and is not a substitute for an exam by your veterinarian.