| Core dog vaccines | Distemper, parvovirus, adenovirus (hepatitis), rabies (American Animal Hospital Association (AAHA) Canine Vaccination Guidelines) |
| Core cat vaccines | Panleukopenia, herpesvirus-1, calicivirus, rabies (American Association of Feline Practitioners (AAFP) Vaccination Guidelines) |
| Typical puppy/kitten series start | 6–8 weeks of age (AAHA and AAFP vaccination guidelines) |
| Rabies vaccine legal status | Required by law in most US states for dogs; required in many states for cats (Varies by state and local jurisdiction) |
| Adult booster frequency (core) | Every 1–3 years depending on vaccine and regulations (AAHA Canine Vaccination Guidelines) |
What Makes a Vaccine 'Core' or 'Non-Core'?
Veterinary organizations classify vaccines into two categories based on disease severity, how easily an infection spreads, and whether the disease poses a risk to humans. Understanding this distinction helps you have more informed conversations with your vet.
| Core dog vaccines | Distemper, parvovirus, adenovirus (hepatitis), rabies (American Animal Hospital Association (AAHA) Canine Vaccination Guidelines) |
| Core cat vaccines | Panleukopenia, herpesvirus-1, calicivirus, rabies (American Association of Feline Practitioners (AAFP) Vaccination Guidelines) |
| Typical puppy/kitten series start | 6–8 weeks of age (AAHA and AAFP vaccination guidelines) |
| Rabies vaccine legal status | Required by law in most US states for dogs; required in many states for cats (Varies by state and local jurisdiction) |
| Adult booster frequency (core) | Every 1–3 years depending on vaccine and regulations (AAHA Canine Vaccination Guidelines) |
Core vaccines are recommended for virtually every pet of a given species, regardless of lifestyle or location. They protect against diseases that are highly contagious, often life-threatening, or pose a public health risk. Non-core vaccines are given selectively — your veterinarian weighs your pet's individual exposure risk, geographic region, and daily environment before recommending them.
Neither category is unimportant. A non-core vaccine may be just as critical for one animal as a core vaccine is for another. The classification is about baseline population-level need, not urgency for any specific pet. See what your pet's annual wellness exam actually covers to understand how vets use this information during routine visits.
Core Vaccines for Dogs and Cats
For dogs, veterinary consensus identifies the following as core vaccines:
- Canine distemper — a serious viral illness affecting the respiratory, gastrointestinal, and nervous systems
- Canine parvovirus — highly contagious and potentially fatal, particularly in puppies
- Canine adenovirus (hepatitis) — protects against infectious canine hepatitis
- Rabies — legally required in most US states; fatal and transmissible to humans
The first three are commonly delivered together in a combination shot often called the DA2PP or DHPP vaccine. Puppies typically receive a series of these starting around 6–8 weeks of age, with boosters every 3–4 weeks until about 16 weeks old, followed by boosters in adulthood.
For cats, core vaccines include:
- Feline panleukopenia (feline distemper) — a severe and often fatal parvoviral disease
- Feline herpesvirus type 1 and feline calicivirus — major causes of upper respiratory infections
- Rabies — required by law in many states, even for indoor-only cats
The first three are routinely combined in the FVRCP vaccine. Kitten series typically begin at 6–8 weeks and follow a similar interval schedule to dogs.
Core vaccine
A vaccine recommended for all pets of a given species due to the severity, prevalence, or public health risk of the disease it prevents. These form the baseline of every pet's preventive care plan.
Non-core vaccine
A vaccine given based on an individual pet's risk factors, such as geographic location, lifestyle, or level of contact with other animals. Non-core does not mean unimportant — it means not universally required.
Titer test
A blood test that measures the concentration of antibodies against a specific disease, used to assess whether a pet retains protective immunity from prior vaccination.
Booster
A follow-up dose of a vaccine given after the initial series to maintain or renew immunity over time. Booster intervals vary by vaccine and local regulations.
Zoonotic disease
An infection that can be transmitted between animals and humans. Some vaccine-preventable diseases, such as rabies and leptospirosis, fall into this category.
Non-Core Vaccines and When They Apply
Non-core vaccines address real diseases — they're simply not universally necessary. Your veterinarian will assess your pet's lifestyle before making recommendations.
For dogs, common non-core vaccines include:
- Bordetella bronchiseptica (kennel cough) — recommended for dogs that visit groomers, dog parks, boarding facilities, or training classes
- Leptospirosis — a bacterial infection spread through contaminated water or wildlife contact; often advised for dogs in rural or flood-prone areas. This disease can also affect humans, making it relevant to zoonotic disease awareness for families.
- Lyme disease — recommended in tick-heavy regions; pairs well with year-round parasite prevention strategies discussed in flea, tick, and heartworm prevention
- Canine influenza — advised for dogs with frequent close contact with other dogs
For cats, non-core vaccines include:
- Feline leukemia virus (FeLV) — strongly recommended for outdoor cats or those in multi-cat households with unknown FeLV status; considered core by some guidelines for kittens
- Feline immunodeficiency virus (FIV) — risk-based recommendation for outdoor cats with fighting exposure
- Chlamydophila felis and Bordetella — considered in multi-cat environments with respiratory disease history
Building vaccination decisions into a broader weekly pet care routine helps ensure these conversations happen at the right intervals.
Booster Schedules and Titer Testing
Vaccines don't provide lifelong immunity in a single dose. Booster schedules vary by vaccine type, product, and your pet's health history.
49 states
US states with rabies vaccination laws for dogs
Rabies vaccination is legally mandated for dogs in nearly every US state, and for cats in a growing number of jurisdictions.
3–4 weeks
Interval between puppy or kitten series doses
Veterinary guidelines recommend doses spaced 3–4 weeks apart during the initial series to build adequate immunity.
After the initial puppy or kitten series, many core vaccines are boosted at one year and then every one to three years depending on the product and local regulations. Rabies boosters, in particular, are often legally mandated on a one- or three-year schedule depending on the state and vaccine used.
Titer testing is a blood test that measures antibody levels to assess whether a pet still has protective immunity from a previous vaccine. Some veterinarians use titers to help determine whether a booster is currently needed, though titers don't replace rabies vaccination where law requires it. Ask your vet whether titer testing makes sense for your pet's situation.
Adult pets that are new to your home and have an unknown or incomplete vaccination history may need to restart some series. Your veterinarian can help design a catch-up schedule. For a complete picture of what a vet evaluates during these visits, see what a wellness exam actually covers.
This article provides general educational information about pet vaccination and is not a substitute for personalized veterinary advice. Always consult a licensed veterinarian to determine the right vaccination plan for your specific pet.