For dogs who need protection against both Lyme disease and Leptospirosis, getting fully vaccinated has always meant at least two separate injections. That changed this summer.
On June 15, 2026, Elanco received USDA approval for TruCan Ultra Lyme-L4, the first 1/2 mL combination Leptospirosis/Lyme vaccine for dogs. The approval marks a meaningful step for practices looking to simplify preventive care protocols and for pet owners who have been hesitant to add another injection to their dog's annual visit.
Why This Combination Matters
Leptospirosis and Lyme disease are both increasingly relevant threats. Leptospirosis is a bacterial infection spread through water and soil contaminated by infected animals. It is also zoonotic, meaning it can pass from dogs to people. In 2024, the American Animal Hospital Association updated its Canine Vaccination Guidelines to designate Leptospirosis as a core vaccine for all dogs, regardless of lifestyle or geography.
George Moore, DVM, PhD, Professor Emeritus of Epidemiology at Purdue University College of Veterinary Medicine, framed the stakes:
Lyme disease, carried by ticks, is also expanding its geographic reach. The Companion Animal Parasite Council's 2026 annual parasite forecast points to continued spread of tick populations across the U.S., putting more dogs at risk each year. Both diseases require annual boosters, unlike the three-year core distemper-adenovirus-parvovirus combination. That scheduling similarity makes a single injection covering both a natural fit.
The Compliance Gap
Despite clear veterinary guidance, protection rates fall short. A 2020 study found that only 63.4% of dogs current on core vaccines had received a Leptospirosis vaccine in the preceding 14 months. Lyme numbers were lower still: in the 11 states identified by the CDC as high-risk for Lyme disease, only 47.9% of dogs current on core vaccines were also current on Lyme vaccine.
Vaccine hesitancy in pet owners compounds the problem. A 2023 study found that 52% of dog owners exhibited some degree of canine vaccine hesitancy, a trend researchers link in part to spillover from debates around human vaccination.
Jill Pattee, DVM, Medical Strategy Lead for Infectious Diseases at Elanco, sees the new combination vaccine as a direct response to that resistance. She noted that TruCan Ultra Lyme-L4 "may help pet owners say 'yes' to vaccine protection from Lyme disease" by eliminating the need for a second injection. Research in human pediatric medicine, across studies published in 2007, 2009, and 2017, has consistently found that combination vaccines improve overall vaccination compliance.
Fewer Injections, Less Stress
The practical benefits extend beyond compliance. Fear Free veterinary care has made reducing injection counts a recognized priority. Every additional needle stick increases the stress of a visit, for dogs and owners alike. A single injection that covers two annual vaccines fits naturally into that philosophy.
For pet owners who have postponed appointments precisely because they anticipated multiple shots, the lower injection burden may remove a meaningful barrier to care.
Bringing Vaccines to the Door
Even with a simplified vaccine, annual veterinary visits still require scheduling, transportation, and managing a dog who may not love the waiting room. That friction is real, and it contributes to the compliance gaps the data shows.
For practices looking to close that gap, at-home vet tech visits offer a practical path. When a practice partners with Homelove, a Fear-Free certified Caregiver can administer vet-approved vaccines, including annual boosters like the new Lyme and Leptospirosis combination, at the client's home. The practice retains the clinical relationship and directs the care; Homelove handles getting a trained technician to the door.