| Puppy/kitten series start age | 6–8 weeks (American Animal Hospital Association (AAHA) guidelines) |
| Series completion age | Around 16 weeks (AAHA and American Association of Feline Practitioners (AAFP)) |
| Rabies vaccine: legally required in most U.S. states | Yes (Varies by state and county — verify local law) |
| Typical adult booster interval (DAP/FVRCP) | Every 1–3 years (Depends on vaccine product and individual risk assessment) |
| FeLV vaccine recommendation | All kittens; adult cats with outdoor or multi-cat exposure (AAFP feline vaccination guidelines) |
| Bordetella recommended for | Dogs that board, groom, or socialize regularly (AAHA canine vaccination guidelines) |
Core vs. Non-Core Vaccines: What the Difference Means
Veterinary guidelines divide pet vaccines into two categories: core and non-core. Understanding the distinction helps you have more informed conversations with your vet.
Core vaccine
A vaccine recommended for all pets of a given species, regardless of lifestyle, because the targeted disease is widespread, severe, or a public health risk.
Non-core vaccine
A vaccine given only to pets with specific risk factors — such as outdoor access, geographic location, or frequent contact with other animals.
Booster
A follow-up dose of a vaccine given after the initial series to maintain or renew immune protection over time.
Maternal antibodies
Protective proteins passed from a mother to her offspring through milk. They offer early immunity but can temporarily block vaccine effectiveness, which is why puppy and kitten vaccine series are spread out over weeks.
Titer test
A blood test that measures the level of antibodies to a specific disease, sometimes used to assess whether a pet still has protective immunity from a prior vaccine.
Core vaccines are recommended for virtually every dog or cat, regardless of lifestyle, because the diseases they prevent are either highly contagious, potentially fatal, or transmissible to humans. Non-core vaccines are given selectively, based on a pet's specific risk factors — where they live, how they spend time outdoors, whether they board or visit dog parks, and similar considerations.
This framework, established by veterinary professional organizations, means your neighbor's indoor-only cat and your hiking companion dog will likely need different vaccine combinations — and that's by design. For a broader look at how vaccines fit into your pet's overall health plan, see our guide to preventive vs. reactive pet care.
Vaccine Schedules for Dogs
For puppies, vaccinations typically begin between 6 and 8 weeks of age and are given in a series every 3–4 weeks until around 16 weeks. This staged approach is necessary because maternal antibodies — passed from the mother through milk — can interfere with vaccine effectiveness early in life. The series allows immunity to build as those maternal antibodies fade.
| Puppy/kitten series start age | 6–8 weeks (American Animal Hospital Association (AAHA) guidelines) |
| Series completion age | Around 16 weeks (AAHA and American Association of Feline Practitioners (AAFP)) |
| Rabies vaccine: legally required in most U.S. states | Yes (Varies by state and county — verify local law) |
| Typical adult booster interval (DAP/FVRCP) | Every 1–3 years (Depends on vaccine product and individual risk assessment) |
| FeLV vaccine recommendation | All kittens; adult cats with outdoor or multi-cat exposure (AAFP feline vaccination guidelines) |
| Bordetella recommended for | Dogs that board, groom, or socialize regularly (AAHA canine vaccination guidelines) |
Core Dog Vaccines
- Distemper, Parvovirus, Adenovirus (DAP/DHPP): Started at 6–8 weeks, boosters every 3–4 weeks until 16 weeks, then again at 1 year. Adults typically receive boosters every 1–3 years depending on the product and local regulations.
- Rabies: First dose as early as 12 weeks (required by law in most U.S. states); booster at 1 year, then every 1–3 years per local law.
Common Non-Core Dog Vaccines
- Bordetella (kennel cough): Recommended for dogs that board, visit groomers, or interact regularly with other dogs.
- Leptospirosis: Often suggested for dogs with outdoor exposure, especially near wildlife or standing water.
- Lyme disease: Relevant in tick-endemic regions.
- Canine influenza: Considered for high-exposure social dogs.
Vaccine Schedules for Cats
Kittens follow a similar early-life series to puppies, starting around 6–8 weeks. Even cats that stay strictly indoors generally need core vaccines — indoor cats can be exposed to airborne pathogens, escape briefly, or encounter a new pet brought into the home.
Core Cat Vaccines
- FVRCP (Feline Viral Rhinotracheitis, Calicivirus, Panleukopenia): Series begins at 6–8 weeks, boosters every 3–4 weeks until 16 weeks, then at 1 year, then every 1–3 years.
- Rabies: Recommended — and required by law in many states — starting at 12 weeks.
Common Non-Core Cat Vaccines
- Feline Leukemia Virus (FeLV): Strongly recommended for kittens and cats with any outdoor access or exposure to other cats.
- Feline Immunodeficiency Virus (FIV): Discussed based on outdoor lifestyle and exposure risk.
Getting started on the right foot with vaccines is just one piece of early pet ownership. Our new pet owner's health guide covers first vet visits and other foundational steps.
Why Timing and Boosters Matter
Vaccine immunity is not always permanent. Titers — blood tests that measure antibody levels — can sometimes inform booster decisions, but many local rabies laws require boosters on a fixed schedule regardless. Skipping or delaying boosters, especially in areas with active disease risk, can leave pets vulnerable.
Adult pets adopted without vaccination records present a common challenge. In most cases, vets restart a series or administer a single catch-up dose and recheck as needed — never assume prior vaccinations are current without documentation.
Watch for Post-Vaccine Reactions
Mild lethargy or injection-site tenderness for 24–48 hours is considered normal after vaccination. Severe reactions — including facial swelling, hives, vomiting, or difficulty breathing — are rare but require immediate veterinary attention. Always let your vet know about any prior vaccine reactions before your pet receives future doses.
Vaccines can occasionally cause mild, short-lived reactions — slight lethargy or soreness at the injection site for a day or two. Severe reactions are rare. Contact your vet promptly if your pet experiences facial swelling, vomiting, difficulty breathing, or collapse after any vaccine. Always discuss your pet's full health history with your veterinarian before each visit, especially if managing chronic conditions.
Keeping a simple home vaccine log helps you stay on schedule. Pairing that habit with the seasonal pet health checklist can make annual preventive care feel manageable rather than daunting. For a full picture of what happens at a routine appointment, our annual vet visit breakdown walks through the details.
This article is for general informational purposes only and is not a substitute for professional veterinary advice. Always consult a licensed veterinarian for guidance specific to your pet's health needs.