Core Every dog or cat should have these, whatever its lifestyle. They cover diseases that are widespread and serious. Non-core Recommended only when where you live or how the animal lives puts it at risk. Not recommended Not enough evidence to justify giving them anywhere. Those are the definitions the World Small Animal Veterinary Association uses, and the American guidelines follow the same split.
Dogs
| Vaccine | Status | Puppies | Adults |
|---|---|---|---|
| Distemper, adenovirus, parvovirus | Core | Start at 6 to 8 weeks, repeat every 2 to 4 weeks until 16 weeks or older | Booster at about 6 months, then no more than every 3 years |
| Rabies | Core where required by law or the disease is present | From 12 weeks | Booster at 1 year, then every 1 or 3 years depending on the product and your state's law |
| Leptospirosis | Core for US dogs under the 2024 AAHA update | Two doses 2 to 4 weeks apart from 12 weeks | Every year |
| Bordetella (kennel cough) | Non-core | One dose of the nasal or oral type | Every year if the dog boards, goes to daycare or is groomed |
| Lyme | Non-core | Two doses from about 8 weeks | Every year, before tick season, in tick areas |
| Canine influenza | Non-core (US only) | Two doses from 6 weeks | Every year for dogs kept with many others: kennels, shows, daycare |
| Canine coronavirus | Not recommended | Weak evidence it matters in adult dogs | |
Leptospirosis is the one that has moved. WSAVA calls it core wherever the disease is common, and AAHA updated its US guideline in 2024 to make it core for every dog, on the grounds that almost every dog in North America is at risk. Small city dogs get it from rodent urine. It also spreads to people, which is covered in what you can catch from your pet.
Cats
| Vaccine | Status | Kittens | Adults |
|---|---|---|---|
| Panleukopenia, herpesvirus, calicivirus | Core | Start at 6 to 8 weeks, repeat every 3 to 4 weeks until 16 to 20 weeks | Booster at about 6 months, then every 3 years for a low-risk cat; up to yearly for a cat that goes out or lives with many others |
| Rabies | Core where required by law or the disease is present | From 12 weeks | Per the product label and your state's law |
| Feline leukemia (FeLV) | Core under 1 year; non-core for low-risk adults | Two doses | Yearly if the cat goes outdoors or lives with cats of unknown status; every 2 to 3 years if low risk |
| Chlamydia, Bordetella | Non-core | Mainly for large multi-cat households and shelters with confirmed disease | |
| FIP | Not recommended | Cannot be shown to reliably prevent the disease | |
| FIV | Not available in the US | Sold only in Japan, Australia and New Zealand | |
An indoor cat still needs the core three and, in most places, rabies. Many state and local laws require it even for cats that never go out, and bats get into houses.
Antibodies from the mother protect a young animal for its first weeks and also block vaccines from working. They fade at different ages in different animals, which is why the series is repeated every few weeks: each dose is a fresh attempt for the ones whose maternal antibodies have just dropped. By 16 weeks nearly all have. A few still have not, which is why the current advice is a booster at about six months rather than waiting a full year. That closes the gap for the small number that were not yet protected, without adding a dose over a lifetime.
A titer measures antibody in the blood. For distemper, adenovirus and parvovirus in dogs, and panleukopenia in cats, a positive result is good evidence the animal is protected, and WSAVA supports testing from 20 weeks to confirm a puppy or kitten responded to its series. Two limits. A negative result does not reliably mean the animal is unprotected, though vets generally treat it as a reason to revaccinate. And titers tell you nothing useful about the cat herpes or calici viruses. AAHA does not suggest routine titers for most dogs; it reserves them for animals that have reacted to a vaccine before, or when an owner would otherwise decline vaccines altogether.
A study of more than 4.6 million dogs found an adverse event at 19.4 per 10,000 visits, about 0.19%. Reactions were more likely in smaller dogs, younger dogs, and when several vaccines were given at once. In cats, a reaction in the 30 days after vaccination was reported in 0.52%, most of it a day or two of tiredness, low appetite, mild fever or a sore spot. Anaphylaxis is rare, around 1 to 5 in 10,000.
Small dogs get the same dose as large dogs. The volume on the label is the minimum that produces protection, and cutting it can leave the animal unprotected. If your small dog has reacted before, the answer is to space vaccines across visits, not to shrink the dose.
Any swelling of the face, hives, repeated vomiting, or collapse in the hours after a vaccine is an emergency. Being quiet and off food for a day is expected.
National averages from a 2025 survey: distemper-parvo combination about $42, rabies $35, leptospirosis $34, Bordetella $38, canine influenza $53, Lyme $50. For cats, the core combination about $34 and rabies $31. A retail vaccine clinic's full puppy or kitten series, three visits with deworming, runs $269 to $299 depending on the city, before any rabies license fee. Shelters and low-cost clinics are cheaper. A full veterinary practice costs more and includes an exam.
The vaccine record is one of the documents a breeder should hand over. How to check a breeder before you pay covers the rest.