UC Davis VMTH Canine and Feline Vaccination Guidelines

Introduction

The UC Davis VMTH vaccination guidelines below have been based on published studies and recommendations made by the American Animal Hospital Association (AAHA) and the World Small Animal Veterinary Association (WSAVA), which include representatives from academia, private practices, governmental regulatory bodies, and industry. These groups have evaluated the benefits versus risks of the vaccines currently available on the market. Interested readers are referred to documents published by these groups for further information (see References and Resources listed at the end of this document). The document below has been generated by a group of faculty and staff at UC Davis School of Veterinary Medicine for the purposes of VMTH veterinary student education and as a reference for referring veterinarians. These are guidelines, as the vaccine types recommended and the frequency of vaccination vary depending on the lifestyle of the pet being vaccinated, i.e. indoor vs outdoor pets, travel plans, kennel/boarding plans, and underlying disease conditions such as immune-mediated diseases. Because these factors may change over time, we recommend the vaccination plan for each individual pet be decided by the owner at routine annual examinations, following a discussion between the veterinarian and the client regarding the animal’s lifestyle in the year ahead. A previous history of vaccination reactions in an individual pet will also affect recommendations for vaccination. For all vaccines given, the product, expiration date, lot number, route and location of injection should be documented in the record.

Research in companion animal vaccinology, as with other areas of medicine, is an ongoing process and we are dedicated to continuing to review new studies and recommendations in order to generate optimal recommendations for vaccination of dogs and cats. As further research is performed, and as new vaccines become available on the market, this document will be continuously updated and modified.

I. Canine Vaccination Guidelines

Canine Core Vaccines

Core vaccines are recommended for all puppies and dogs with an unknown vaccination history. The diseases involved have significant morbidity and mortality and are widely distributed, and in general, vaccination results in relatively good protection from disease. These include vaccines for canine parvovirus (CPV), canine distemper virus (CDV), canine adenovirus-1 (CAV-1), and rabies. In addition, the leptospirosis vaccine is now recommended as a core vaccine for dogs because the disease has the potential to occur in any dog (even in urban environments), can be life-threatening, and the vaccines are considered safe and efficacious, with recent improvements in safety over the last decade.

Canine Parvovirus, Distemper Virus, and Adenovirus-2 Vaccines

For initial puppy vaccination (£ 16 weeks), one dose of vaccine containing modified live virus (MLV) CPV, CDV, and CAV-2 is recommended every 3-4 weeks from 6-8 weeks of age, with the final vaccine in the series being given no earlier than 16 weeks of age. Vaccination with CAV-2 stimulates immunity to CAV-1 (and CAV-2) but is less likely to be associated with adverse events than vaccination with CAV-1. For dogs older than 16 weeks of age, two doses of vaccine containing modified live virus (MLV) CPV, CDV, and CAV-2 given 3-4 weeks apart are recommended, although a single vaccine may be sufficient in the absence of maternal antibody. After vaccination at 16-18 weeks, an additional vaccine is recommended at 6 months (to immunize any dogs that had maternal antibody at 16-18 weeks of age), followed by revaccination every 3 years thereafter, ideally using a product approved for 3-year administration, unless there are special circumstances that warrant more or less frequent revaccination. Note that recommendations for recombinant CDV vaccines are different from the above. These vaccines are not currently stocked by our drug room or routinely used at the VMTH.

Canine Rabies Virus Vaccines

According to California state law, all dogs must have received a rabies vaccine by the time they are 4 months of age, with the minimum age being 12 weeks. Therefore, we recommend that puppies receive a rabies vaccine at 12 weeks to 16 weeks of age. Adult dogs with unknown vaccination history should also receive a single dose of rabies vaccine. A booster is required one year later, and thereafter, rabies vaccination should be performed every 3 years using a vaccine approved for 3-year administration.

Canine Leptospira Vaccines

Multiple leptospiral serovars can cause disease in dogs, and minimal cross-protection is induced by each serovar. Currently available vaccines do not contain all serovars, and duration of immunity is not less than 12 months; some manufacturers have guarantees on protection for up to 15 months after vaccination. We recommend annual vaccination of all dogs with vaccines containing all four Leptospira serovars (Grippotyphosa, Pomona, Canicola and Icterohaemorrhagiae); this means that all dogs be evaluated annually by a veterinarian and vaccinated for leptospirosis. The initial vaccination should be followed by a booster 3-4 weeks later, and the first vaccine be given as early as label recommendations permit (6 weeks of age for some manufacturers; note that maternal antibody interference is not relevant for leptospirosis vaccination because immunity does not depend on replication of vaccinal organisms). Due to improvements in vaccine composition, reaction rates for vaccines containing Leptospira now approximate those for other core vaccines. Risk assessment should be considered for dogs that have had previous reactions to Leptospira vaccines and pre-medication and observation should be considered at the time of vaccination; however, it should be noted that the risk of reactions tends to decrease with age. The VMTH does not recommend administering different vaccine antigens at separate time points because it reduces the chance that vaccines will be administered, there is a lack of evidence that it decreases reaction risk, and it can contribute to vaccine interference (where the immune response to one vaccine interferes with the immune response to a second vaccine administered within a 2-3 week interval).

The second rabies vaccine can be administered at the time of the third leptospirosis vaccination (one year of age).
 

Canine Non-Core Vaccines

Non-core vaccines are optional vaccines that should be considered in light of exposure risk, ie. based on geographic distribution and the lifestyle of the pet. Several of the diseases involved are often self-limiting or respond readily to treatment. Vaccines considered as non-core vaccines are canine parainfluenza virus (CPiV), canine influenza virus H3N2, Bordetella bronchiseptica, and Borrelia burgdorferi. Vaccination with respiratory vaccines is generally less effective in protecting against disease than vaccination with the core vaccines.

Canine Parainfluenza Virus and Bordetella bronchiseptica

These are both agents associated with canine infectious respiratory disease complex (CIRDC) in dogs. For Bordetella bronchiseptica, annual mucosal vaccination with live avirulent bacteria is recommended for dogs expected to board, be shown, or to enter a kennel situation within 6 months of the time of vaccination. We currently stock a mucosal (oral or intranasal) vaccine containing both B. bronchiseptica and canine parainfluenza virus. For puppies and previously unvaccinated dogs, only one dose of this vaccine is required (recommendations differ for the parenteral, inactivated form of this vaccine). Most boarding kennels require that this vaccine be given within 6 months of boarding; the vaccine should be administered at least one week prior to the anticipated boarding date. Annual booster vaccination with B. bronchiseptica and parainfluenza vaccines is considered adequate for protection.

Canine Influenza Virus (CIV)

Canine influenza virus H3N8 emerged in the US in greyhounds in Florida in 2003, then caused respiratory disease in shelters across the US; this subtype is now considered extinct in the US. Canine influenza virus H3N2 emerged in 2015 in Illinois and causes periodic outbreaks of respiratory disease in different parts of the country as a result of reintroductions from Asia through dog importation. Combination H3N8/H3N2 vaccines are available, but at the time of writing, only H3N2 is relevant. Influenza virus vaccines are subtype-specific and do not cross-protect against influenza virus subtypes such as H5N1. Vaccines can reduce clinical signs and virus shedding in dogs infected by CIV. They may be useful for dogs traveling and intermingling with other dog populations. The UC Davis VMTH currently stocks a monovalent H3N2 vaccine.

Canine Borrelia burgdorferi (Lyme) Vaccine

The incidence of Lyme disease in California is currently low. If travel to endemic areas (ie the east coast) is anticipated, vaccination could be considered, followed by annual boosters. Vaccines that stimulate a strong immune response to the OspA outer surface protein of Borrelia burgdorferi are recommended, because they inactivate the bacteria within the tick. Even dogs with evidence of previous exposure (positive blood tests) may benefit from vaccination because reinfection can occur. In general, the UC Davis VMTH does not recommend Lyme vaccination for dogs residing solely in northern California, although there are parts of the state where incidence is higher (e.g., Humboldt county) and vaccination could be considered.
 

Other Canine Vaccines

Several other canine vaccines are currently available on the market. These are vaccines for canine coronavirus and rattlesnake envenomation. The reports of the AVMA and the AAHA canine vaccine task force have listed these vaccines as not generally recommended. The UC Davis VMTH does not stock or routinely recommend use of these vaccines.

Canine Enteric Coronavirus Vaccine

Infection with canine enteric coronavirus (CCV) alone has been associated with mild disease only, and only in dogs < 6 weeks of age. It has not been possible to reproduce the infection experimentally, unless immunosuppressive doses of glucocorticoids are administered. Serum antibodies do not correlate with resistance to infection, and duration of immunity is unknown. In mixed infections with CCV and canine parvovirus (CPV), CPV is the major pathogen. Vaccination against CPV therefore protects puppies from disease following challenge with both canine enteric coronavirus and CPV. Thus, the UC Davis VMTH does not routinely recommend vaccination against canine enteric coronavirus and the vaccine is not stocked by the VMTH.

Canine Rattlesnake Vaccine

The canine rattlesnake vaccine comprises venom components from Crotalus atrox (western diamondback). Although a rattlesnake vaccine may be potentially useful for dogs that frequently encounter rattlesnakes, based on existing evidence, the UC Davis VMTH does not currently recommend routine vaccination of dogs for rattlesnake envenomation, and the vaccine is not stocked by the VMTH.

II. Feline Vaccination Guidelines

In general, guidelines for vaccination of cats have been strongly influenced by the appearance of injection site sarcomas in cats, and in particular their epidemiologic association with feline leukemia virus vaccines and killed rabies virus vaccines. Thus, there is clear evidence for minimizing frequency of vaccination in cats. Risk factors for sarcomas should be discussed with cat owners at the time of examination. If a cat develops a palpable granuloma at the site of previous vaccination, the benefits vs risks of future vaccinations should be carefully considered. All injection site sarcomas should be reported to the vaccine manufacturer.

Feline Core Vaccines

The definitions of core and non-core vaccines described in the canine vaccination guidelines above also apply to the feline vaccines. The core feline vaccines are those for feline herpesvirus 1 (FHV1), feline calicivirus (FCV), feline panleukopenia virus (FPV), feline leukemia virus (FeLV - kittens) and rabies.

Feline Herpesvirus 1, Feline Calicivirus and Feline Panleukopenia Virus Vaccines

For initial kitten vaccination (£ 16 weeks), one dose of parenteral vaccine containing modified live virus (MLV) FHV1, FCV, and FPV is recommended every 3-4 weeks from 6-8 weeks of age, with the final dose being given no sooner than 16 weeks of age. For cats older than 16 weeks of age, two doses of vaccine containing modified live virus (MLV) FHV1, FCV, and FPV given 3-4 weeks apart are recommended, even though a single vaccination is sufficient to induce immunity. The next vaccine should be given at 6 months of age (to immunize any cat that still had maternal antibody at 16 weeks of age) and no later than one year after the 16-week vaccination. Revaccination is then suggested every 3 years thereafter for cats at low risk of exposure. It has been recommended that these vaccines be administered on the right thoracic limb as distally as possible. The use of FPV MLV vaccines should be avoided in pregnant queens and kittens less than one month of age because of the potential for vaccine-associated disease.

Feline Rabies Virus Vaccines

Cats are important in the epidemiology of rabies in the US. In general, we recommend that kittens receive a single rabies vaccine at 12-16 weeks of age, then be revaccinated one year later. Adult cats with unknown vaccination history should also receive a single dose of a rabies vaccine. We currently stock and suggest the use of rabies vaccines licensed for 3-year use. Rabies vaccination should be performed every 3 years using a vaccine approved for 3-year administration. According to previous recommendations to monitor for injection-site sarcomas, rabies vaccines are administered subcutaneously as distally as possible in the right pelvic limb.

Feline Leukemia Virus Vaccine

A number of FeLV vaccines are available on the market, which have shown to be highly efficacious in risk of FeLV-associated disease. We recommend vaccination of all FeLV-negative kittens and any FeLV-negative adult cats allowed to go outdoors or cats having direct contact with other cats of unknown FeLV status; in the absence of resources to determine infection status, we recommend vaccinating all cats at risk for FeLV infection. Vaccination is most likely to be useful in kittens and young adult cats, because acquired resistance to infection develops beyond 16 weeks of age; however, older cats can still become infected with sufficient exposure. Vaccination is not recommended for FeLV-positive cats and isolated indoor-only cats with no likelihood of exposure to FeLV (but should be used for indoor-only cats that are exposed to cats that go outdoors). We do not recommend introducing FeLV-positive cats to households that have FeLV-negative cats, even if the FeLV-negative cats are vaccinated.

The VMTH currently stocks an RNA particle-based vaccine based on preliminary safety and efficacy studies along with the lack of adjuvant and a 2-year duration of immunity.

Initially, two doses of an FeLV vaccine are given at a 3 to 4 week interval starting as early as 8 weeks of age, after which 2-yearly boosters are recommended depending on risk. For the purpose of tracking sarcoma formation, parenteral FeLV vaccines are administered subcutaneously as distally as possible in the left pelvic limb.
 

Feline Non-Core Vaccines

Optional or non-core vaccines for cats consist of the vaccines Chlamydia felis and Bordetella bronchiseptica.

Feline Chlamydia felis Vaccine

Chlamydia felis causes conjunctivitis in cats that generally responds readily to antimicrobial treatment. Immunity induced by vaccination is probably of short duration and the vaccine provides only incomplete protection. The use of this vaccine could be considered for cats entering a population of cats where infection is known to be endemic. However, the vaccine has been associated with adverse reactions in 3% of vaccinated cats, and we do not recommend routine vaccination of low-risk cats with this vaccine. The C. felis vaccine is therefore not stocked by the VMTH drug room.

Feline Bordetella bronchiseptica Vaccine

This is a modified live intranasal vaccine. Bordetella bronchiseptica is primarily a problem of very young kittens, where it can cause severe lower respiratory tract disease. It appears to be uncommon in adult cats and pet cats in general. For these reasons, the UC Davis VMTH does not recommend routine vaccination of pet cats for Bordetella bronchiseptica. The vaccine could be considered for young cats at high risk of exposure in large, multiple cat environments. The UC Davis VMTH drug room does not stock this vaccine.
 

Other Feline Vaccines

The feline infectious peritonitis (FIP) vaccine has been listed as ‘Not Generally Recommended’ by the AAFP.

Feline Infectious Peritonitis Vaccine

The FIP vaccine is an intranasal modified live virus product. The efficacy of this vaccine is controversial, and duration of immunity may be short, although the vaccine appears to be safe. Although exposure to feline coronaviruses in cat populations is high, the incidence of FIP is very low, especially in single-cat households (where it is 1 in 5000). Most cats in cattery situations where FIP is a problem become infected with coronaviruses prior to 16 weeks of age, which is the age at which vaccination is first recommended. Vaccination could be considered for seronegative cats entering a cattery where FIP is common. We do not routinely recommend vaccinating household cats with the FIP vaccine, and the vaccine is not stocked by our drug room.
 

III. References and Resources/Suggested Further Reading

1.    2022 AAHA Canine Vaccination Guidelines (last updated 2024). https://www.aaha.org/resources/2022-aaha-canine-vaccination-guidelines/
2.    2023 ACVIM Leptospirosis Consensus Statement Update. https://onlinelibrary.wiley.com/doi/10.1111/jvim.16903
3.    2024 Guidelines for the Vaccination of Dogs and Cats – compiled by the Vaccination Guidelines Group of the World Small Animal Veterinary Association. https://wsava.org/wp-content/uploads/2024/04/WSAVA-Vaccination-guidelines-2024.pdf
4.    2020 AAHA Feline Vaccination Guidelines. https://www.aaha.org/wp-content/uploads/globalassets/02-guidelines/feline-vaccination-guidlines/resource-center/2020-aahaa-afp-feline-vaccination-guidelines.pdf
 

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