What's new in canine and feline vaccination guidelines?

Updated feline and canine vaccination guidelines have introduced changes that many veterinary practices have yet to fully adopt, including an additional feline viral rhinotracheitis, calicivirus, and panleukopenia (FVRCP) booster for kittens, feline leukemia virus (FeLV) vaccination as core for kittens younger than 1 year of age, and leptospirosis (Lepto) as a core vaccine for all dogs regardless of lifestyle.

Kaitlyn Krebs, DVM, MBA, and Kristen White, DVM, both professors at Rowan University Shreiber School of Veterinary Medicine in Harrison Township, New Jersey, spoke with dvm360 about these guideline updates, the reasoning behind them, and why feline adoption has lagged further behind canine adoption.

Editor’s note: This dvm360 Q&A has been edited and consolidated from a verbal interview to better fit a written format while retaining the substance of the original conversation.

dvm360: Starting with your names, can you share a little bit about yourselves?

Kaitlyn Krebs, DVM, MBA: My name is Katie Krebs, and I am an associate professor in primary care at [Rowan University Schreiber School of Veterinary Medicine], and I've been here for about a year. Before that, I was at the University of Pennsylvania and a variety of other academic institutions.

Kristen White, DVM: I'm Kristen White. I'm a clinical assistant professor in shelter medicine and community engagement. I've been with Schreiber coming up on 4 years, and this is my first academic role. I was a primary care clinician, and then I went into nonprofit shelter medicine and access to care work, and I came from a high-volume, low-cost access to care clinic before I came to Schreiber.

dvm360: What are the most significant changes in the latest canine and feline vaccination guidelines, and what prompted them?

Krebs: Full disclosure, the canine and the feline guidelines are not super new. So, the feline guidelines [were last updated in] 2020, and I guess we can start with cats because cats always get the short end of the straw. But the biggest, a couple of big changes in the recent or the 2020 feline updates. One is around FVRCP vaccines, and so one of the big recommendation updates is recommending that kittens get another FVRCP booster at 6 months of age, whereas historically we would stop between 16 to 20 weeks of age, now they're recommending an additional booster just because about 1/3 of kittens will still have maternal antibodies at that 16 to 20 week age, and so we can’t and don't really know what kittens will be fully protected and what kittens won't, and so by giving them that additional booster, then we can ensure that all the kittens are protected.

The other feline change is around the FeLV vaccine, and so the change in 2020 is to include FeLV as core for all kittens less than a year of age. So that means they get their first 2 doses in that kitten series and booster it at a year of age, and then once the cats are a year of age, it becomes a lifestyle vaccine, which is historically how people have thought of FeLV vaccines as a lifestyle vaccine based on what that cat is doing out in the world.

So those are really the 2 big changes around the feline guidelines, and it's always really interesting to me when I speak about vaccines to veterinary audiences, how many people know about those changes, first of all, and then second of all, how many people implement those changes? And it's actually a lot fewer veterinarians than I would expect. Usually, we think of those guidelines as pretty much like the top-of-the-line recommendations from vaccine experts, and so I think on the feline side, people have been a lot slower to make those changes.

On the canine side, really the biggest change is around Lepto, and so the canine guidelines were initially updated in 2022, ACVIM came out in 2023 with an updated Lepto statement recommending Lepto as core for all dogs, and then AAHA Canine Vaccine Guidelines were updated in 2024. So that was to update Leptospirosis core for all dogs, regardless of their lifestyle, and I think in the veterinary world, people have been a lot more willing to update their vaccine protocols to include Lepto as a core vaccine. I think before the guidelines, most of us were doing that and treating Lepto as core anyway.

So on the canine side, it was a lot smaller of a shakeup, and people really do follow those guidelines. I think a little bit more, but even still, it's been 2 years since those guidelines were updated, and I still am talking to people that don't consider Lepto as core yet. And so, yeah, it's still a major change.

dvm360: Do you have any thoughts on why that contrast is the way that it is? Such as why people tend to be more likely to adopt the canine guidelines quicker than the feline, or do you think it is because it’s Lepto vs FeLV?

Krebs: I think in general, it's a lot easier to get dog owners to get on board with giving a vaccine every single year, and when I'm speaking to dog owners, I can say, ‘Hey, update, Lepto is core. You're coming in for your annual vaccines anyway. This doesn't change anything that we're already doing for your dog, other than giving them a vaccine that we're already recommending.’

I think on the cat side, it's a little bit more difficult to get cats into the vet in general, and I think we were seeing that it's a little bit more challenging for them to come in for their annual exams. We don't see cats every single year, (even though that's our recommendation) and even if they're not getting vaccines, they should be coming in for their wellness checks every single year. And so, as kittens especially, it's a little bit more challenging to get owners to see the value in those added vaccines, and I think from the veterinary side, the FeLV vaccine, especially, it's challenging, and I've seen this in my practice also. It's hard to convince cat owners that we need to give these vaccines, and our talk [at the 2026 AVMA Convention] was about vaccines and the differences. And I do a lot of talking on vaccine hesitancy. That's something that both [White] and I are actually studying in a project this summer. And I think we just see a little bit more of that in the cat world.

And for whatever reason, cat owners are a little bit harder to convince, and I think veterinarians also perhaps don't see the value in doing FeLV, and so don't push as hard to vaccinate those cats as well.

White: I would agree. I think it's definitely some of that asking them to come for that additional booster after they've already come for the kitten series, it's about the additional visit, and then I also think people sometimes with cats they have a reduced perception of risk because the cat is indoor only, and maybe they don't like, they think they don't need these vaccines because they don't have that outside contact, but that's not entirely true all the time.

dvm360: Are there any core vaccines where recommendations have shifted, or is this mostly about refining protocols for non-core vaccines?

Krebs: That does differ depending on whether we're talking about dogs or cats. So if we start with cats, we do see a shift in core vaccines with the updated guidelines because FeLV is considered core for kittens in that less-than-1-year period, and then we do change the timeline of the FVRCP vaccine, which is considered core for all cats. So it's kind of a multi-layered answer there. Even though FeLV is typically considered non-core, we're adding that in as a new core vaccine for kittens, but it remains non-core for older cats. So it's a little bit difficult to fully determine if that's a shift in one or the other. I'd call it a shift in both.

On the canine side, it's a lot more cut and dry. We're adding Lepto as core, whereas before it used to be non-core. So it's not necessarily a new vaccine, but it is a change in the recommendations for our core vaccines, and so we're just kind of adding that into what we consider important for all dogs.

dvm360: Was Lepto not a core vaccine originally because it was more location-based, or what was the reasoning behind that?

Krebs: So Lepto wasn't considered core before, but I think mostly from like a risk analysis standpoint. People historically thought that only our large breed hunting dogs that are out in like the wilderness and doing hunting and interacting with wildlife, they thought those were the dogs that were most at risk of getting Lepto.

But as we do more research, as we get more information, we actually have seen that shift to Lepto being seen more in our little white fluffies living in the city, living in apartments, and those dogs are just as much at risk as our dogs that are out interacting with wildlife in what we think of as a traditional sense. What I like to tell my clients is that Lepto is everywhere. So we have rats in cities. We have wildlife that spread it. Even if you don't think your dog is interacting with wildlife, if your dog comes down from its 18th floor penthouse story apartment and pees on the grass outside, they are certainly coming into contact with areas where wildlife, whether we think of wildlife as a rat or a mouse, it is, and they're coming into contact with areas where those animals have been, which puts them at risk. So all dogs, regardless of where they live, regardless of their size, regardless of what their lifestyle is like, are at risk of getting Lepto, and that's why we've made that change.

Want to hear more from this conversation? Be on the lookout for part 2 coming later this month!