Should my dog get the Lyme vaccine?

The short answer

It depends, and that’s the honest answer. The Lyme vaccine is genuinely contested in veterinary medicine. For dogs that hike Conservation Halton trails frequently or have a history of tick exposure, it’s a reasonable add-on. For dogs reliably on year-round oral preventive with low exposure, it’s optional. The vaccine doesn’t replace a tick preventive — it’s belt-and-suspenders, not a substitute.

What products are available in Canada

Three Lyme vaccines are licensed for dogs in Canada:

• Nobivac Lyme (Merck) — a bacterin that generates both anti-OspA and anti-OspC antibodies, killing spirochetes in both the tick and the dog.
• Vanguard crLyme (Zoetis) — recombinant OspA + chimeric OspC. USDA-labelled for 15-month duration of immunity.
• Recombitek Lyme (Boehringer Ingelheim) — recombinant OspA.

There is no Lyme vaccine for cats.

Why it’s contested

The 2018 American College of Veterinary Internal Medicine (ACVIM) consensus statement on canine Lyme disease could not reach unanimous agreement on routine vaccination. A 2021 OVC-led review in Frontiers in Veterinary Science argued that Lyme vaccines meet the AAHA criteria for “not generally recommended” — meaning consider on a case-by-case basis rather than for every dog. The argument against routine vaccination:

• ~95% of Borrelia-exposed dogs remain asymptomatic. Most exposed dogs never need treatment regardless of vaccine status.
• Clinical Lyme disease in dogs responds well to doxycycline. It’s a treatable infection in dogs that develop it.
• The vaccine doesn’t prevent the other tick-borne diseases. Anaplasmosis, ehrlichiosis, RMSF, babesiosis, and Powassan virus are all carried by the same or overlapping tick species. So a tick preventive is still required regardless.

The argument for vaccination, particularly in high-exposure regions like Halton:

• Layering reduces breakthrough risk. Even excellent oral preventives have rare misses (a missed dose, a delayed kill, a particularly vulnerable bite). Adding the vaccine adds a second line of defence.
• Halton is a hot zone. Local Borrelia-positive tick rates climbed from 0% in 2018 to 38% in spring 2025. The exposure math has changed.
• Lyme nephritis is not an outcome you want to risk. The 5–10% of clinical-Lyme dogs that progress to nephritis can have permanent kidney damage. For the families of those dogs, the vaccine looks like a worthwhile precaution in retrospect.

This is genuinely a judgement call, not a settled question.

A reasonable framework for Halton dogs

Without prescribing remotely, here’s how we typically think through it during a visit:

Reasonable to vaccinate if:

• Your dog frequently hikes Conservation Halton trails (Crawford Lake, Mount Nemo, Rattlesnake Point, Hilton Falls, Mountsberg, Kelso) or off-leash forest properties.
• Your dog has had previous tick exposure or a positive 4DX in the past.
• You anticipate possible gaps in monthly preventive dosing (travel schedule, household stress, etc.).
• Your dog has known proteinuria or kidney concerns and you want to minimize Lyme nephritis risk.

Reasonable to skip if:

• Your dog is a reliable city walker with limited off-leash forest exposure.
• You’re confident you’ll maintain 12-month oral preventive coverage without lapses.
• Your dog has had a vaccine reaction history or other reason to limit non-essential vaccines.

Required either way:

• Year-round tick preventive. The vaccine is not a substitute.
• Daily tick checks during peak season.
• Annual 4DX SNAP test.

What does the vaccine schedule look like?

A typical adult dog protocol:

• Initial series: two doses, 2–4 weeks apart.
• First annual booster: one year after the initial series.
• Subsequent boosters: annually thereafter (or per Vanguard crLyme’s 15-month label, depending on product).

For puppies, we time it alongside other vaccine series — usually starting at 12 weeks.

Side effects

Like any vaccine, the Lyme vaccine can cause local injection-site reactions (mild swelling, brief soreness) and occasional fatigue or appetite suppression for a day. Serious reactions are uncommon. Dogs with a prior history of vaccine reactions should be flagged in the chart and discussed at the visit.

What about cats?

Cats are remarkably resistant to clinical Lyme disease — no naturally acquired clinical case has been documented outside the lab in North America. There is no Lyme vaccine for cats and no current need for one.

What we recommend for the Halton-area dog walker

A reasonable position for many Halton households: prioritize the year-round oral isoxazoline first. Have a discussion with your veterinarian about whether to add the Lyme vaccine based on your dog’s specific lifestyle (frequent off-leash hiking, prior tick exposure) and whether you anticipate gaps in dosing. The vaccine is the layer, not the foundation.

For the bigger picture on Halton’s tick situation, see our 2026 field guide on ticks.

Key takeaways

• Three Lyme vaccines are licensed for dogs in Canada: Nobivac Lyme, Vanguard crLyme, Recombitek Lyme.
• The 2018 ACVIM consensus was non-unanimous; many practices recommend it situationally rather than universally.
• The vaccine does not replace a tick preventive — anaplasmosis, ehrlichiosis, and other tick-borne diseases require separate coverage.
• Reasonable to vaccinate dogs with frequent forest/off-leash exposure or prior tick history.
• Reasonable to skip for reliably city-walking dogs on consistent year-round oral preventive.
• Year-round preventive, daily tick checks, and annual 4DX are required either way.

References

• ACVIM Consensus Statement on Lyme Disease in Dogs (2018).
• 2021 OVC-led review of canine Lyme vaccines, Frontiers in Veterinary Science.
• Companion Animal Parasite Council — Lyme disease in dogs.
• Product monographs for Nobivac Lyme (Merck), Vanguard crLyme (Zoetis), and Recombitek Lyme (Boehringer Ingelheim).