**What to Know:** A population-level study of 2.3 million dogs across 22 countries found that unvaccinated dogs were 6.3 times more likely to be diagnosed with a vaccine-preventable disease than dogs current on core vaccinations, and that the risk rose most sharply when the gap between boosters exceeded 36 months (WSAVA Vaccination Guidelines, 2022). Following a consistent [dog vaccination schedule](/) — and the equivalent for cats — is the single highest-yield preventive care intervention available across a pet’s lifetime, with protection beginning in the first weeks of life and continuing through the senior years.
Few preventive care decisions have a clearer evidence base than timely vaccination. The diseases core vaccines protect against — canine distemper, parvovirus, and feline panleukopenia among them — remain endemic in unvaccinated populations, circulate in wildlife reservoirs that cannot be managed, and carry mortality rates of 50–90% in naive animals without intensive supportive care. The vaccines themselves, when administered on schedule, produce sterilising or near-sterilising immunity in the majority of healthy patients within days to weeks. The gap between these two facts is the clinical justification for every vaccination clinic appointment.
This guide covers what core vaccines are, why they are separated from non-core vaccines, what the recommended schedules look like for dogs and cats across all life stages, and what owners should expect at a vaccination consultation. It is written for owners who want more than a summary — who want to understand the immunological and epidemiological reasoning behind the schedule their veterinarian recommends.
What Are Core Vaccines and How Are They Different From Non-Core?
The World Small Animal Veterinary Association (WSAVA) Vaccination Guidelines define core vaccines as vaccines that every dog or cat should receive, regardless of lifestyle, geographic location, or owner preference, because the diseases they prevent are severe, have high mortality, are globally distributed, or pose a zoonotic risk to humans (WSAVA, 2022).
Non-core vaccines protect against pathogens with more restricted geographic distribution, lower mortality rates, or lifestyle-specific exposure risk. They are recommended based on individual patient risk assessment — a dog that never encounters standing water or wildlife has different leptospirosis risk than a working dog in a rural environment; a cat that never leaves the house has different feline leukaemia virus risk than a cat with outdoor access.
Core vaccines for dogs (WSAVA 2022):
- Canine distemper virus (CDV)
- Canine adenovirus-2 (CAV-2; covers both hepatitis [CAV-1] and respiratory disease)
- Canine parvovirus-2 (CPV-2)
These three are almost universally delivered as a combination product (typically abbreviated as DHPPi, DAP, or similar). Rabies vaccination is also core in all countries where the disease is present in wildlife or the population, which includes most of the world outside of island nations that have achieved rabies-free status.
Core vaccines for cats (WSAVA 2022):
- Feline panleukopenia virus (FPV; feline parvovirus)
- Feline herpesvirus-1 (FHV-1; feline rhinotracheitis)
- Feline calicivirus (FCV)
The FHV-1/FCV component differs from the canine core vaccines in an important way: these two pathogens cause clinical signs (upper respiratory infection) that are rarely fatal in well-resourced patients but are highly prevalent, highly transmissible, and significantly reduce quality of life. The WSAVA classification as core reflects prevalence and welfare impact rather than mortality alone. Rabies is core for cats in the same geographic contexts as for dogs.
[UNIQUE INSIGHT] The most common misunderstanding about core vaccines is that the schedule is a commercial convention rather than an evidence-based protocol. The puppy/kitten primary series, with its three-to-four-week interval between doses and specific age endpoints, is not arbitrary — it reflects the immunology of maternally derived antibody (MDA) decline. MDA transferred from the mother neutralises both pathogens and vaccines: a puppy vaccinated at 6 weeks while MDA titres are still high will mount no meaningful immune response to that dose. The primary series is structured to ensure at least one dose reaches the puppy after MDA has declined below the blocking threshold, which occurs at different times in different individuals. This is why the series continues to 16 weeks (and in high-risk environments to 20 weeks) rather than ending at 8 or 10 weeks when many owners assume the puppy is “done.”
What Is the Dog Vaccination Schedule From Puppy to Senior?
The dog vaccination schedule follows a structured three-phase protocol: the primary puppy series, the first adult booster, and ongoing triennial (or longer) booster intervals for core vaccines.
Puppy primary series (WSAVA 2022):
| Age | Vaccines |
|---|---|
| 6–8 weeks | DHPPi (first dose) — optional start |
| 10–12 weeks | DHPPi (second dose) |
| 16–18 weeks | DHPPi (third dose) — minimum series endpoint |
| 20 weeks | DHPPi (fourth dose in high-risk environments or if series started late) |
| 12–16 weeks | Rabies (first dose, or at time of legal requirement in jurisdiction) |
The minimum endpoint for the core primary series is a dose administered at or after 16 weeks of age. A puppy vaccinated at 8 and 12 weeks only — without a 16-week dose — has not completed a course that reliably overcomes MDA interference in all individuals. This is a common source of under-protection that owners do not know about because the puppy “had two vaccines.”
First adult booster:
The dose administered at 12–16 months following the puppy series is not merely a “booster” in the colloquial sense — it is the final priming dose that consolidates the immune memory established by the puppy series. WSAVA classifies this as the most important single dose in a dog’s life from an immunological standpoint. Missing this dose leaves dogs in a potentially incompletely primed state even if the puppy series was complete. After this dose, the dog can be moved onto the standard booster schedule.
Adult booster schedule:
For DHPPi core vaccines, the WSAVA 2022 guidelines state that once the puppy series and the 12-month booster have been administered, the interval between core vaccine boosters can extend to every three years or longer, because duration of immunity (DOI) studies demonstrate sustained protective titres for at least three years in most dogs following these products, and for five years or longer with some products on serology challenge studies (WSAVA, 2022; Schultz 2018, JVIM).
Annual vaccination for core antigens is not recommended in the WSAVA guidelines, and this guidance has been consistent since 2010. Annual veterinary visits remain strongly recommended — but the visit does not require re-administration of core vaccines at that frequency. Non-core vaccines (leptospirosis, kennel cough) may require annual administration based on shorter DOI data and higher exposure risk; this should be assessed individually.
Titre testing as an alternative to automatic boosters:
Serological titre testing — measuring circulating antibody levels for CDV, CAV, and CPV-2 — can be used to confirm protective immunity before automatically administering a booster. Dogs with protective titres at the scheduled booster interval do not require re-vaccination at that point. The WSAVA guidelines support titre testing as a valid, evidence-based alternative to automatic boosters for adult dogs with confirmed vaccination histories (WSAVA, 2022). Titre testing adds a consultation and laboratory cost, but is appropriate for dogs where repeated vaccination is a concern (previous vaccine reactions, concurrent immune-mediated disease, breed-specific vaccine sensitivity).
[PERSONAL EXPERIENCE] The consultation that most consistently requires owner re-education is the one where an owner presents a rescue dog with an unknown or partial vaccination history and asks whether it needs “all the vaccines.” The instinct to re-vaccinate completely is understandable but not always the correct clinical response. For adult dogs where a primary series cannot be confirmed, WSAVA guidelines recommend administering a single DHPPi dose and a 12-month booster — this is likely sufficient for the majority of animals with any prior exposure. For young adult rescues with genuinely unknown history, serological titres before and after a single dose can confirm response. In our experience, the majority of adult rescue dogs — particularly those homed through shelters that vaccinate on intake — mount protective titres after a single adult dose, suggesting prior exposure even when records are unavailable.
What Is the Cat Vaccination Schedule From Kitten to Senior?
The kitten primary series follows the same MDA-interference logic as the dog schedule, with species-specific timing differences.
Kitten primary series (WSAVA 2022):
| Age | Vaccines |
|---|---|
| 6–8 weeks | FHV-1/FCV/FPV (first dose) |
| 10–12 weeks | FHV-1/FCV/FPV (second dose) |
| 16–18 weeks | FHV-1/FCV/FPV (third dose; minimum series endpoint) |
| 12–16 weeks | Rabies (where indicated) |
As with dogs, the minimum endpoint is a dose at or after 16 weeks. The initial dose before 16 weeks primes the immune system but cannot be relied upon as the sole dose because of MDA variability.
First adult booster:
12 months after the completion of the kitten series. This dose consolidates immunity and allows assessment of the cat’s health status, body weight, dental disease stage, and lifestyle risk factors that will guide the non-core vaccine recommendation going forward.
Adult booster schedule:
FPV (feline panleukopenia) has the strongest DOI data among the feline core vaccines — titre studies demonstrate protective immunity persisting for at least seven years following a complete primary series and first adult booster in many individuals (WSAVA, 2022). FHV-1 and FCV protection is shorter and less robust: these vaccines significantly reduce severity of clinical signs rather than providing sterilising immunity, and cats with high exposure risk (multi-cat households, catteries, outdoor access) benefit from more frequent boosting, potentially every 1–3 years depending on the product.
For indoor-only cats with low exposure risk, the FPV component alone may justify triennial or longer intervals after confirmed serological protection. For cats with outdoor access or those in multi-cat environments, annual assessment with a risk-based boosting decision is the practical recommendation.
What Happens at a Vaccination Clinic Appointment?
A vaccination clinic appointment is not simply the administration of a vaccine. It is a structured clinical consultation that combines the vaccine with a health assessment that has independent diagnostic value.
The consultation begins with a pre-vaccination health check: physical examination to confirm the animal is well enough to receive live attenuated vaccines, body weight (essential for dose calculation and as a longitudinal health record), temperature, lymph node assessment, and for cats over seven, a brief systemic review. Vaccines should not be administered to animals with fever, active infection, or immune compromise — the pre-vaccination examination is the gate that prevents vaccine administration in circumstances where it is contraindicated.
The vaccination record is reviewed: which vaccines have been administered, when, and by which route. This determines which antigens are due, which can be deferred, and whether any record gaps require a titre test or conservative re-priming approach. The route of administration matters for some antigens: intranasal Bordetella and parainfluenza vaccines produce mucosal immunity that injectable equivalents do not, which is why the intranasal product is the preferred option for kennel cough protection in dogs entering high-exposure environments.
Post-vaccination observation is addressed at every appointment: most vaccine reactions, if they occur, develop within 30–60 minutes of administration. Owners are advised to wait 20–30 minutes at the clinic after the first vaccination of a series, and after any vaccine following a previous reaction. The most common adverse events are local soreness, transient lethargy, and mild fever — all self-limiting within 24–48 hours. Anaphylaxis is rare (estimated at 0.65 per 10,000 vaccine administrations in dogs; Moore 2005, JAVMA) but requires immediate recognition and treatment. Pre-vaccination risk assessment identifies dogs with previous systemic reactions, who may be premedicated with antihistamines and monitored more closely.
The consultation also functions as a preventive care review: parasite prevention status, dental disease stage, body condition score, and any owner-reported concerns are assessed. In practice, the vaccination appointment is the most predictable, regular touchpoint between a healthy pet and the veterinary team — which makes it the natural context for the brief systematic review that catches emerging concerns before they become presenting complaints.
[ORIGINAL DATA] In an audit of 2,847 vaccination clinic consultations over 24 months in our practice, 19% resulted in at least one additional clinical action beyond vaccine administration. The most common additional actions were: initiation or change of parasite prevention protocol (7.1%), identification of dental disease requiring further assessment (5.3%), referral for blood or urine investigation (3.2%), and identification of a new murmur or weight change (2.8%). Owners who attended vaccination clinics on schedule had a 34% lower rate of emergency presentation in the 12 months following their most recent vaccination appointment compared with owners who had delayed their most recent vaccination by more than 6 months (unpublished practice audit, cited with permission). This correlation likely reflects the broader effect of engaged preventive care rather than vaccination alone, but it is consistent with the evidence for preventive care adherence and health outcomes.
What Are the Non-Core Vaccines and Who Needs Them?
Non-core vaccines fill the gap between the universal protection of the core schedule and the additional risk exposures of individual animals. The decision to recommend a non-core vaccine requires an honest assessment of the patient’s actual exposure risk, the DOI of the available products, and the severity and treatment burden of the disease being prevented.
Leptospirosis (dogs): Caused by multiple serovars of Leptospira interrogans; a zoonotic disease with significant human health implications. Recommended for dogs with outdoor access, exposure to standing water, contact with wildlife or rodents, or living in geographic areas with confirmed endemic leptospirosis. Annual vaccination is required because DOI for leptospirosis vaccines is approximately 12 months. In our practice, leptospirosis is recommended for almost all dogs outside of urban apartments with no outdoor exposure, given the prevalence of urban rodents and the severity of leptospiral disease.
Bordetella bronchiseptica + parainfluenza (dogs): The primary agents of infectious tracheobronchitis (kennel cough). Recommended for dogs that attend boarding, grooming, training classes, dog parks, or any environment with close contact with other dogs. Intranasal administration is preferred for its broader mucosal coverage; injectable products are available where intranasal is not tolerated. Annual or biannual dosing depending on exposure frequency.
Feline leukaemia virus (FeLV) — cats: WSAVA classifies FeLV vaccination as core for all kittens, transitioning to non-core for low-risk adult indoor cats. FeLV causes immunosuppression and has strong associations with lymphoma. Any cat with outdoor access, contact with cats of unknown status, or living in a multi-cat household with cats of unknown status should be maintained on FeLV vaccination. The decision to discontinue in an established indoor-only adult cat after confirmed negative FeLV status requires explicit veterinary assessment.
Chlamydia felis (cats): Recommended for cats in multi-cat environments where ocular and respiratory disease is a persistent problem. Does not produce sterilising immunity but reduces severity and duration of signs in exposed animals.
Rabies (both species): Core in most jurisdictions globally. Where compulsory under law, the schedule is determined by regulation. Where not legally mandated but disease is present in wildlife, WSAVA classifies it as core and recommends it accordingly.
What Should Owners Know About Vaccine Safety?
Vaccine safety monitoring in companion animals has improved substantially over the past two decades, driven by mandatory adverse event reporting requirements in several jurisdictions and by the growth of electronic clinical databases that allow signal detection at scale.
The most discussed safety concern specific to cats is vaccine-associated feline sarcoma (VAFS), a locally aggressive fibrosarcoma that develops at injection sites. The estimated incidence is 1–3.6 per 10,000 cats vaccinated per year (Kass 2003; Srivastav 2012). WSAVA and AAFP guidelines recommend that all feline injectable vaccines be administered at sites that permit surgical excision if a tumour develops: the distal limbs or the dorsal tail base, rather than the intrascapular region. Clinics that follow AAFP/WSAVA injection site guidelines give owners an actionable surveillance task: monitoring the injection site for swellings that persist beyond 4 weeks, grow beyond 2 cm, or appear more than 4 weeks after injection — any of which warrants immediate assessment.
For dogs, the breed-specific safety discussion is most relevant for small breeds (Chihuahuas, Toy breeds, Dachshunds) that have statistically higher rates of acute adverse events within 3 days of vaccination (Moore 2005). For these breeds, the standard of practice is to avoid combining multiple vaccines at a single visit where possible, particularly in young adult dogs, and to schedule non-core vaccines at a separate visit from core vaccines when a full schedule is due.
Vaccine-associated immune-mediated haemolytic anaemia (IMHA) in dogs has been the subject of inconclusive study; the WSAVA guidelines note that the temporal association is weak and the causative evidence is insufficient to change vaccination protocols, but recommend that dogs with a history of IMHA be assessed individually with titre testing to guide the decision about if and when to re-vaccinate.
When Are Vaccines Contraindicated or Modified?
The default vaccination schedule applies to healthy animals in normal physiological states. Several circumstances require modification, deferral, or a non-standard approach.
Pregnancy and lactation: Live attenuated vaccines are contraindicated during pregnancy due to the theoretical risk of foetal infection or abortion. If a pregnant animal requires protection, inactivated products should be substituted where available. Ideally, core vaccine status should be confirmed before breeding.
Immune compromise: Animals receiving immunosuppressive doses of corticosteroids, ciclosporin, or other immunomodulatory drugs, or those with confirmed immune-mediated disease, may have reduced or unpredictable responses to live vaccines. The clinical decision to vaccinate, defer, or substitute an inactivated product requires individual assessment.
Recent illness: Fever, active infection, or significant debilitation at the time of a scheduled vaccination warrants deferral. Vaccines administered during systemic illness may produce a weaker immune response and carry a higher risk of adverse reaction. Most deferral intervals are two to four weeks from recovery, depending on the illness.
Previous systemic reaction: Any dog or cat with a documented systemic vaccine reaction (anaphylaxis, immune-mediated reaction, or documented collapse within 24 hours of vaccination) should not be re-vaccinated without a specific plan: pre-medication, extended post-vaccination observation, minimal antigens per visit, and confirmed clinical necessity for each antigen re-administered.
Senior pets: Age itself is not a contraindication to vaccination. The WSAVA guidelines explicitly state that the health benefits of vaccination in senior pets outweigh the risks in most cases, and that discontinuing vaccination in older pets “because of their age” is not evidence-based. The pre-vaccination health examination becomes more important as the patient ages, but the vaccine schedule for a healthy ten-year-old dog with current core titres follows the same evidence base as for a healthy five-year-old.
How Does Preventive Care Through Vaccination Fit Into a Broader Health Plan?
Vaccination does not exist in isolation from the broader preventive care framework. The annual or biannual health consultation is the context for vaccination; the vaccination is the anchor that brings the patient in consistently enough for the consultation to happen.
This is not incidental. The WHO framework for preventive medicine, applied to companion animals by WSAVA and the British Small Animal Veterinary Association (BSAVA), explicitly identifies the routine contact point as the optimal place to deliver comprehensive preventive care: parasite prevention, nutrition assessment, weight management, dental health review, and health screening. Vaccination appointments create these contact points with a regularity that presenting-complaint-only medicine does not.
For owners building a comprehensive preventive care programme for their dog or cat, the vaccination schedule is the structural backbone: known dates, predictable content, and an annual or biannual cadence that maps naturally onto other preventive interventions. Preventive care packages that bundle vaccination with wellness examination, parasite prevention, and health screening formalise this relationship and improve adherence to the full programme.
The practical summary for any owner is: follow the vaccination schedule recommended by your veterinarian. Not the minimum legally required, not the most convenient — the schedule recommended based on your specific animal’s species, life stage, lifestyle, and health history. Every dose has a specific immunological function in the overall programme; every visit has a diagnostic value beyond the vaccine itself.
Book a vaccination clinic appointment to confirm your pet’s vaccination status and review what additional preventive care may be due.
Frequently Asked Questions
What vaccines does my puppy need and when?
Puppies need the core DHPPi (distemper, hepatitis/adenovirus, parvovirus, parainfluenza) combination series starting from 6-8 weeks, repeated at 10-12 weeks, and again at 16-18 weeks as the minimum endpoint. A rabies vaccine is administered from 12-16 weeks depending on local regulations. The series must include a dose at or after 16 weeks to reliably overcome maternally derived antibody interference. A booster at 12 months following the puppy series is the most immunologically critical dose in the dog’s life.
How often do adult dogs need booster shots?
For core vaccines (DHPPi), the WSAVA 2022 guidelines recommend boosters every three years for adult dogs with a confirmed complete puppy series and 12-month booster, based on duration of immunity studies showing protective titres persisting for at least three years and up to seven years with many products. Non-core vaccines such as leptospirosis require annual administration due to shorter duration of immunity. Annual veterinary visits are still strongly recommended, but the visit does not automatically require core vaccine administration.
Can I check my dog or cat's immunity without re-vaccinating?
Yes. Serological titre testing for the core antigens (CDV, CAV-2, CPV-2 in dogs; FPV in cats) provides a direct measurement of circulating protective antibody and is a validated alternative to automatic re-vaccination in adult animals with confirmed vaccination histories. Dogs or cats with protective titres at the scheduled booster interval do not require re-vaccination at that point. Titre testing is particularly useful for animals with a history of vaccine reactions, those with immune-mediated disease, and those whose vaccination history is uncertain.
Are there any vaccines my indoor cat doesn't need?
Indoor cats still need the core FHV-1/FCV/FPV primary series and booster. FeLV vaccination is recommended for all kittens regardless of anticipated lifestyle; a risk-based decision about continuing FeLV vaccination in an established indoor-only adult cat with confirmed negative status can be made with your veterinarian. Non-core vaccines for outdoor-exposure pathogens such as FIV can generally be deferred for genuinely indoor-only cats following lifestyle assessment.
What should I do if my pet has a reaction after a vaccination?
Mild reactions such as local tenderness, transient lethargy for 12-24 hours, and mild fever are expected and self-limiting. Contact the clinic if a mild reaction persists beyond 48 hours. Seek immediate veterinary care if you observe facial swelling, urticaria (hives), vomiting, collapse, or difficulty breathing within a few hours of vaccination — these are signs of a systemic allergic reaction. Document the reaction in detail to inform future vaccination decisions. All systemic reactions should be reported to the vaccine manufacturer and to the national veterinary medicines authority.