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Frequently Asked Questions

Common FAQs

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VACCINATION SITES

Have vaccination site recommendations been stipulated for the cat?

The 2020 AAHA/AAFP Task Force recognizes and supports the value of the 2013 AAFP Vaccination Advisory Panel for vaccinating in specific places in the distal limbs (FPV, FHV-1, FCV below the right elbow, FeLV below the left stifle, and rabies below the right stifle). However, in the 2020 update, the Task Force also recognizes that practitioners may need to use discretion regarding the anatomical location of vaccine administration. Practitioners are strongly advised to continue avoiding the space between the scapulae, and to keep accurate records for site, vaccination type, and route of vaccination administration.

Is it OK if I continue to use the vaccination sites from the 2013 AAFP Vaccination Advisory Panel recommendations?

Yes.

DETERMINING FeLV RISK

Why is feline leukemia a core vaccine?

FeLV is a core vaccination for all kittens up to and including 1 year of age and for at-risk cats. Vaccination of all kittens is highly recommended because, compared with adult cats, kittens are much more susceptible to progressive infection, FeLV-associated disease, and death if exposed to FeLV. i Additionally, a kitten’s lifestyle and risk of exposure to FeLV often changes in the first year of life.

When should an adult cat receive a revaccination for feline leukemia?

This requires a risk-assessment through a discussion with the pet owner and understanding which type of feline leukemia vaccine is available.

  • FeLV (recombinant [live canary-pox vector]): Vaccinate 12 months after the last dose in the series, then annually for individual cats who are at high risk of regular exposure through encountering FeLV+ cats and cats of unknown FeLV status either indoors or outdoors.
  • FeLV (inactivated): Vaccinate at 12 months after the last dose in the series, then consider the following schedule for boostering:
    • Annually for individual cats who could be regularly exposed through living with FeLV+ cats or cats of unknown FeLV status either indoors or outdoors.
    • Every two to three years, where product licensure allows, for individual adult cats who are less likely to have regular exposure to FeLV+ cats. ii,iii,*

*There is a lack of data to make definitive recommendations on the appropriate revaccination interval for at-risk cats. The consensus of the Task Force is revaccination every two to three years in periodic exposure situations in mature cats.iv

How can I tell if an adult cat is “high-risk” or “low-risk” for feline leukemia?

  • High-risk = regular exposure to FeLV through encountering FeLV+ cats either indoors or outdoors (e.g., spending time or living with another cat who spends most of the day outdoors unsupervised, in contact with infected cats, or in a multiple-cat home where the status of all cats is not known.)
  • Low-risk = less likely to have regular exposure to FeLV+ cats (e.g., households with a small number of cats whose status is known to be negative, or cats with limited, supervised, or no outdoor access.)

INTERVALS BETWEEN VACCINES

What is the optimal interval between vaccines and why?

The minimum vaccination interval during the primary series is 2 weeks, and the maximum recommended interval is 4 weeks. Kittens presented 6 weeks or longer following administration of the previous dose of vaccine should receive at least two doses of vaccine, 3 to 4 weeks apart. Although feline-specific data do not exist, extrapolation from mice and humans suggests that a 3-week interval is optimal for induction of memory T-cells after administration of a modified-live virus.v,vi

Does this 2- to 4-week interval apply to different antigens? (For example, what if I vaccinate a cat for rabies at 12 weeks of age, but the FPV-FHV-1-FCV booster is due a week later because of when the kitten first received it?)

The 2-week minimum interval applies to all vaccines. If the rabies is given at 12 weeks of age, then wait an extra week to give the FPV-FHV-1-FCV booster. Each vaccine event (giving one vaccine antigen or multiple vaccine antigens) must be separated by two weeks to avoid vaccine interference.

Can vaccine be administered weekly to kittens that may be at high risk of exposure to an infectious pathogen?

Regardless of the vaccine being administered (parenteral), a minimum vaccination interval of 2 weeks is recommended. REASON: Transient, postvaccination down-regulation of the immune response and cytokine production may compromise the effect of a second vaccine dose administered within 10 to 12 days following administration of the first dose.

How does the 2-week minimum vaccination interval recommendation apply to shelter-housed cats?

Cats arriving at shelters are typically vaccinated against FHV-1, FCV, and FPV on intake. If placed within 2 weeks of intake, rabies vaccine is typically administered at the time of release for cats > 12 weeks of age. The Task Force recommends vaccination against rabies at the time of release because of potential vaccine interference from previous vaccinations given within the preceding 2 weeks. However, this can be handled by repeating a rabies vaccine at a time 2 weeks from all other vaccine events. The cat’s new veterinarian should be consulted about the best way to proceed.

Do senior cats need to continue to be vaccinated?

Yes, standard vaccination protocols should continue—less frequent vaccination is not advised due to inherent immunosenescence. Further, more frequent vaccination is not warranted in senior patients with a lifelong history of immunization, as data from other species suggests the memory response remains intact throughout life and protective immunity can be effectively maintained between revaccinations.

Do antibody titers for FHV-1, FCV, FPV and FeLV correlate to immunity to those diseases?

Most cats that have a positive result on a titer test for feline panleukopenia are immune to the disease. Titers for feline herpesvirus-1 and feline calicivirus may not necessarily correlate well with protective immunity and should not be used to predict protection or need for vaccination. Titers for feline leukemia virus do not correlate with immunity and should not be used to determine the need for vaccination.

OVERDUE FOR CORE VACCINES

How should I vaccinate a cat who is overdue for core vaccines (with the exception of rabies)?

Low-Risk Environment:

  • For kittens < 16 weeks of age, revaccinate every 2 to 4 weeks until no earlier than 16 weeks of age. The assumption here is that maternal antibody is still present at the time of the first of this series of vaccinations.
  • For cats > 16 weeks of age, give one attenuated live vaccine or two inactivated vaccines 3 weeks apart. The assumption here is that maternal antibody is not present.

High-Risk Environment (eg., shelter):

  • For kittens < 20 weeks of age, revaccinate every 2 weeks until no earlier than 20 weeks of age. The assumption here is that maternal antibody is still present at the time of the first of this series of vaccinations.
  • For cats > 20 weeks of age, give two attenuated live vaccines 2 to 3 weeks apart. Inactivated vaccines are not recommended in these environments. The assumption here is that maternal antibody is not present.

What if a cat is years overdue for a vaccination?

Though evidence exists that even inactivated vaccines have longer than label described DOI, the Tasks Force recommends that overdue cats be revaccinated with a single dose of attenuated or inactivated vaccine. If a cat is overdue for an inactivated vaccine by more than 2 years, an initial vaccine, followed by a booster in 2 to 4 weeks is advised. This is true for any inactivated or killed product (including the canary-pox vectored FeLV vaccine).

For rabies vaccination, consider visiting rabiesaware.org for additional information on managing cats overdue for a rabies vaccine. 

Do antibody titers for FHV-1, FCV, FPV and FeLV correlate to immunity to those diseases?

Most cats that have a positive result on a titer test for feline panleukopenia are immune to the disease. Titers for feline herpesvirus-1 and feline calicivirus may not necessarily correlate well with protective immunity and should not be used to predict protection or need for vaccination. Titers for feline leukemia virus do not correlate with immunity and should not be used to determine the need for vaccination.

 

Protocols—Kittens

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OVERDUE FOR CORE VACCINES

How should I vaccinate a kitten who is overdue for core vaccines (with the exception of rabies)?

Low-Risk Environment:

  • For kittens < 16 weeks of age, revaccinate every 2 to 4 weeks until no earlier than 16 weeks of age. The assumption here is that maternal antibody is still present at the time of the first of this series of vaccinations.
  • For kitten > 16 weeks of age, give one attenuated live vaccine or two inactivated vaccines 3 weeks apart. The assumption here is that maternal antibody is not present.

High-Risk Environment (e.g., shelter):

  • For kittens < 20 weeks of age, revaccinate every 2 weeks until no earlier than 20 weeks of age. The assumption here is that maternal antibody is still present at the time of the first of this series of vaccinations.
  • For kittens > 20 weeks of age, give two attenuated live vaccines 2 to 3 weeks apart. Inactivated vaccines are not recommended in these environments. The assumption here is that maternal antibody is not present.

FPV: 6-MONTH BOOSTER

Why has the Task Force recommended to revaccinate a kitten at 6 months of age against FPV, FHV-1, and FCV?

In this update, the Task Force has adopted the same recommendation of revaccination for FPV, FHV-1, and FCV at 6 months of age to potentially reduce the window of susceptibility in kittens who had MDA towards the end of the kitten series (16 to 18 weeks).

During administration of the series, a window exists when MDA concentrations are high enough to interfere with immunization, but are not sufficient to prevent natural infection. This window of susceptibility can be minimized by decreasing the interval between vaccinations in the series—although use of intervals < 2 weeks can interfere with successful immunization, especially with attenuated live vaccines.

Once vaccination has been successfully achieved after the decline of MDA, it is generally recommended that a booster vaccine be given at 3 to 4 weeks. This means the series must be extended 3 to 4 weeks beyond the period in which the decline in MDA occurs, with the final vaccination dose being a booster. In the past, it was recommended that revaccination be performed one year after the initial kitten series, then for most vaccines, every 3 years thereafter. However, due to studies that suggest up to one-third of kittens may fail to respond to a final core vaccine at 16 weeks and may have blocking MDA at 20 weeks, the WSAVA recommends that the 1-year vaccine (feline viral rhinotracheitis-calicivirus-panleukopenia only) be replaced with revaccination at 6 months of age.ix,x,xi

 

NUTRITIONAL DEFICIENCY

Should young cats presented with clinically significant nutritional deficiency receive a vaccine dose?

In practice, the postvaccination immune response in a severely malnourished animal cannot be accurately predicted. However, the benefit of vaccination can outweigh the risk of a suboptimum immune response in the face of a nutritional deficiency. This is especially important in a shelter or other high-risk setting.

MATERNAL ANTIBODY INTERFERENCE

If a kitten fails to receive colostrum (maternally derived antibody) during the first 3 days of life, will it derive any passive antibody protection from the dam?

A kitten receives little to no immune protection in the absence of colostrum. IGG has been shown to be absorbed within 16 hours of birth, but not after 16 hours of birth.xv,xvi

When vaccinating kittens, what is the window of susceptibility?

Maternally derived antibody (MDA) represents passive immunity (mostly colostrum-derived) that naturally declines during the first few months of life. There is a point at which the antibody-level falls below the threshold for protection against natural challenge and yet may be sufficient to interfere with vaccine antigen. This window of susceptibility occurs between the age at which MDA falls below protective levels and the age at which vaccination actually immunizes the kitten. Despite having been “vaccinated,” the kitten is not immunized and remains susceptible to infection if exposed during this period.

If a kitten fails to receive colostrum (maternally derived antibody or MDA), should it be vaccinated during the first few weeks of life?

In practice, colostrum-deprived kittens should not be vaccinated until 4 weeks of age. In shelter medicine protocols, administration of core vaccines to kittens as young as 4 weeks of age is common because of the population density and exposure risk.

How can colostrum-deprived kittens be protected against the core diseases?

In kittens, maternal immunity is almost exclusively derived from colostrum ingestion.

Can maternally derived antibody (MDA) interfere with active immunization by both modified-live virus (attenuated) and killed (inactivated) vaccines?

Maternally derived antibody variably interferes with immunization subsequent to both modified-live virus (attenuated) and killed (inactivated) vaccine administration. The ability of MDA to interfere and the duration of interference are determined by several factors, including the queen’s immune status, her willingness to nurse in the first three days postpartum, and the amount of colostrum received by the individual kitten.

Protocols—Adult Cats

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DETERMINING FeLV RISK

When should an adult cat receive a revaccination for feline leukemia?

This requires a risk-assessment through a discussion with the pet owner and understanding which type of feline leukemia vaccine is available.

  • FeLV (recombinant [live canary-pox vector]): Vaccinate 12 months after the last dose in the series, then annually for individual cats who are at high risk of regular exposure through encountering FeLV+ cats and cats of unknown FeLV status either indoors or outdoors.
  • FeLV (inactivated): Vaccinate at 12 months after the last dose in the series, then consider the following schedule for boostering:
    • Annually for individual cats who could be regularly exposed through living with FeLV+ cats or cats of unknown FeLV status either indoors or outdoors.
    • Every 2 to 3 years, where product licensure allows, for individual adult cats who are less likely to have regular exposure to FeLV+ cats. ii,iii,*

*There is a lack of data to make definitive recommendations on appropriate revaccination interval for at-risk cats. The consensus of the Task Force is revaccination every 2 to 3 years in periodic exposure situations in mature cats.iv

How can I tell if an adult cat is “high-risk” or “low-risk” for feline leukemia?

  • High-risk = regular exposure to FeLV through encountering FeLV+ cats either indoors or outdoors (e.g., spending time or living with another cat who spends most of the day outdoors unsupervised or in contact with infected cats, or in multiple-cat home where the status of all cats is not known.)
  • Low-risk = less likely to have regular exposure to FeLV+ cats (e.g., households with a small number of cats whose status is known to be negative, or cats with limited, supervised or no outdoor access.)

 

OVERDUE FOR CORE VACCINES

How should I vaccinate a cat who is overdue for core vaccines (with the exception of rabies)?

Low-Risk Environment:

  • For cats > 16 weeks of age, give one attenuated live vaccine or two inactivated vaccines 3 weeks apart. The assumption here is that maternal antibody is not present.

High-Risk Environment (e.g., shelter):

  • For cats > 20 weeks of age, give two attenuated live vaccines 2 to 3 weeks apart. Inactivated vaccines are not recommended in these environments. The assumption here is that maternal antibody is not present.

What if a cat is years overdue for a vaccination?

Though evidence exists that even inactivated vaccines have longer than label described DOI, the Tasks Force recommends that overdue cats be revaccinated with a single dose of attenuated or inactivated vaccine. If a cat is overdue for an inactivated vaccine by more than 2 years, an initial vaccine, followed by a booster in 2 to 4 weeks is advised. This is true for any inactivated or killed product (including the canary-pox vectored FeLV vaccine).

 

SINGLE DOSE OF  FCV + FHV-1 + FPV

Will a single dose of FHV-1, FCV, FPV vaccines provide any benefit to the cat?

In the absence of maternally derived antibody (especially cats > 20 weeks of age), one dose of these vaccines should provide a protective immune response. However, administration of two doses of a core vaccine, 3 to 4 weeks apart, is an acceptable alternative for young adult cats receiving initial doses of core vaccines.

CROSS-PROTECTION

To what extent do feline vaccines provide cross-protection?

There is some evidence that dual-strain calicivirus vaccines may be able to provide improved protection against a greater variety of calicivirus variants. (6), xvii Many different strains of FCV cause virulent systemic calicivirus disease (VSD). Current vaccines may not provide protection against all these strains.

Panleukopenia vaccine provides cross-protection against parvovirus strains that infect cats.

Vaccine Handling and Administration

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MIXING VACCINES

Can different types of vaccines be mixed in the same syringe?

No. Unless specifically stated on the product label (package insert), different vaccines should never be combined in the same syringe prior to administration.

Can different vaccines (not part of a single commercial product) be administered to the same cat at the same appointment?

Yes. Different vaccine types can be administered to the same patient at different sites. For example, if a combination vaccine (such as feline viral rhinotracheitis (FHV-1), feline calicivirus (FCV), feline panleukopenia virus (FPV)) is administered subcutaneously (SQ) distal on the right front leg, a killed (inactivated) rabies vaccine could be administered SQ distal on the right rear leg.

REDUCED VOLUME

Should a small cat or kitten receive the same volume of a parenterally administered vaccine as a large cat?

Unlike pharmaceuticals (the dose of which is usually based on weight), a vaccine dose is not based on volume per body mass (size), but rather on the minimum immunizing dose (inactivated vaccine) or the minimum infectious dose (attenuated vaccine). In addition, arbitrary reduction of the volume of a vaccine dose has not been shown to reduce the risk of an acute adverse reaction or enhance safety. IMPORTANT: The entire dose should be administered as directed by the manufacturer. Administering less than the prescribed dose may not induce a protective immune response.

Does vaccine loss following intranasal administration of vaccine (e.g., Intranasal FHV-1, FCV, FPV, Bordetella vaccines) compromise the degree of immunity a patient derives from that dose?

Loss of a small amount of vaccine is expected during or immediately after oral or intranasal administration. All mucosal vaccines contain a concentration of attenuated (live) viruses/bacteria that exceeds the minimum concentration needed to immunize the individual cat.

ROUTE OF ADMINISTRATION

Should vaccine intended for parenteral administration be administered by the intranasal (IN) route?

No, always follow label instructions on administration of the vaccine.

Is there any benefit to the simultaneous administration of intranasal FHV-1/FCV vaccine and parenteral FHV-1/FCV vaccine at the same appointment?

The use of a combination of IN and SQ could provide improved protection. xii

Can an intranasal vaccine be administered by the oral route?

No, always follow label instructions on administration of the vaccine.

Should a disinfectant (e.g., alcohol) be applied to the injection site before administering a vaccine?

Doing so is not generally recommended because a disinfectant might inactivate a modified-live virus (attenuated) product and is not known to provide any benefit to the patient.

STABILITY

How long is a vaccine stable after being reconstituted?

Vaccines should always be stored and handled according to the manufacturer’s instructions. After reconstitution, a vaccine should ideally be used immediately, but certainly within one hour.

TYPES OF IMMUNITY

What is nonsterile immunity?

Several feline vaccines serve only as an aid in the prevention of clinical signs, rather than complete (absolute) prevention of infection. Nonsterile immunity is a term that has been used to describe the quality of immune response following vaccination. It occurs when a vaccine diminishes the severity of disease, but does not completely prevent infection, development of clinical signs, or shedding following exposure (e.g., FHV-1, FCV, and FeLV vaccines).

What is sterile immunity?

Certain feline vaccines are highly immunogenic and provide complete protection from infection. Sterile immunity implies no risk of developing clinical illness and shedding if the vaccinated patient is subsequently exposed to the pathogen (e.g., rabies virus and FPV).

CROSS-PROTECTION

To what extent do feline vaccines provide cross-protection?

There is some evidence that dual-strain calicivirus vaccines may be able to provide improved protection against a greater variety of calicivirus variants. (6), xvii Many different strains of FCV cause virulent systemic calicivirus disease (VSD). Current vaccines may not provide protection against all these strains.

Panleukopenia vaccine provides cross-protection against parvovirus strains that infect cats.

VACCINE RISK TO HUMANS

Is there a known risk to humans who experience inadvertent exposure to an intranasal feline vaccine containing FHV-1, FPV, FCV, or Bordetella?

Transient shedding of attenuated (avirulent live) organisms is likely to occur following intranasal administration to cats. However, the actual risk to humans, if exposed to attenuated bacteria, has not been definitively established. Infection risk to immune-compromised persons from the transient postvaccination shedding following intranasal or vaccine has been raised as a concern by physicians (oncologists, transplant specialists, etc.).

Rabies Vaccinations: Titers, Exemptions, and Protocols

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PROTOCOL—RABIES

Why is a single, initial dose of killed (inactivated) rabies vaccine able to immunize a cat, whereas two doses (2 to 4 weeks apart) are required for all other killed vaccines?

All feline rabies vaccines licensed in the United States are either inactivated (killed) or recombinant technology vaccines. Conventionally, two sequential doses of an inactivated vaccine, administered 2 to 4 weeks apart, are required to immunize (e.g., FCV, FHV-1, and FPV in young cats). Rabies virus vaccine is an exception. Like other inactivated vaccines, the initial dose of a rabies vaccine serves as the “priming” dose. If a cat, after having received only one dose of rabies vaccine, is subsequently exposed to virulent rabies virus, exposure to the virulent virus then serves as the second, or immunizing, “dose.” Because the onset of signs of rabies is slow (weeks to months) following exposure, there is adequate time for a protective, humoral immune response to develop. For this reason, rabies infection in vaccinated cats, even among those having received a single dose, is exceptionally rare.

How long does a single rabies vaccine protect feral cats against infection?

Although there are no reports of long-term evaluation in feral cats, vaccine-licensing studies have demonstrated 3- to 4-year DOI following a single vaccine administered to laboratory kittens. This suggests that, while the first rabies vaccine may only be recognized by regulatory agencies as valid for a single year, vaccinated cats are likely protected for much longer.

EXEMPTIONS TO RABIES VACCINATION

In locations that require cats to be vaccinated against rabies, can a licensed veterinarian exempt the requirement if the patient is sick or there is a risk of an adverse reaction or other injury to the patient?

Most states do NOT authorize point-of-care exemptions to the rabies vaccination requirement (see www.rabiesaware.org). In states and jurisdictions that require it, rabies vaccine must be administered at the appropriate interval, regardless of the cat’s age or state of health, unless rabies-vaccination-exemption authority is specifically defined by the state statute or regulation.

Currently, a small number of states grant point-of-care rabies-vaccination-exemption authority to veterinarians. Some allow exemptions only with the approval of a designated public health official (usually a veterinarian). Exemptions may be allowed in the event an individual cat is determined to be sufficiently ill or if rabies vaccination poses a potential threat to life. Physical examination and medical record documentation of the illness is likely required. It is the responsibility of the owner and the veterinarian to ensure the cat is revaccinated when or if the underlying medical condition resolves.

NOTE: Among cases in which a rabies vaccination exemption has been approved and is in effect, the “exempted” cat will not be considered “currently vaccinated” (immunized) if the rabies booster interval (i.e., either 1-year or 3-year) has been exceeded.

Due to the potential implications associated with rabies exposure in a cat that is not “currently vaccinated” against rabies, the owner should be involved in the decisionmaking process of whether or not to vaccinate, and the veterinarian should document the discussion in the patient’s medical record.

Veterinarians practicing in locations where rabies vaccination is required, but exemption authority is not specifically defined, should contact the State Public Health Veterinarian or provincial Department of Health (Ontario) for guidance on this issue before vaccinating a cat with a medical condition that, in the veterinarian’s judgment, precludes administration of rabies vaccine.

Should cats be vaccinated against rabies in areas where it is not required by law?

With the exception of Hawaii, cats in all US states and cats in all countries or counties with endemic rabies of any species should be vaccinated against rabies, even if not required in that jurisdiction.

OVERDUE FOR RABIES BOOSTER

If a healthy cat is overdue for a rabies booster (and has documentation of prior vaccination), what is the appropriate protocol for revaccination?

In a majority of the states and counties that require rabies vaccination of cats, administration of a single dose of rabies vaccine, regardless of the time that has lapsed since the previous dose was administered, is considered to be an immunizing dose. In most states, following revaccination, a cat is considered to be immediately “currently vaccinated” against rabies. In most states, the duration of immunity of the booster dose is determined by the product label (i.e., either 1-year or 3-year). Some states require all cats overdue for revaccination, even if by just one day, to receive two rabies vaccine doses 1 year apart. (For your state, see www.rabiesaware.org).

ANTIBODY TESTING

Does a “positive” rabies antibody test result correlate with protective immunity?

No. At least not in a legal sense. IMPORTANT: In the United States and Canada, a “positive” test result for rabies virus neutralizing antibody (RVNA) is not recognized as an index of protective immunity and cannot be used in lieu of revaccination. As of 2017, RVNA (regardless of the methodology used), denotes prior vaccination only and is predominantly limited to use in dog/cats being exported from the United States/Canada to rabies-free countries/regions of the world. Testing is a requirement imposed by the importing country/region as a means of confirming recent vaccination against rabies and is not regarded as evidence of protective immunity against rabies.

After receiving a single, initial dose of rabies vaccine, will a cat have a “positive” fluorescent antibody virus neutralization (FAVN) test result for a full year?

Not likely. The antibody test result (FAVN) performed in cats that have received a single, initial dose of rabies vaccine can be expected to manifest a “positive” test result for a limited time (up to about 3 months) postvaccination. Age of the cat and individual patient response to vaccine antigen influence the amplitude and duration of serologic response following a single dose of rabies vaccine. Cats undergoing FAVN testing prior to exportation are more likely to have a negative (“failing”) test result if they have received a single dose of vaccine versus two or more doses.

Unique Conditions

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IMMUNE SUPPRESSION

Does glucocorticoid treatment interfere with vaccine immunity during the initial vaccination series (kittens) or following administration of a booster dose of vaccine (adult)?

Studies in dogs and humans suggest that short-term (days) glucocorticoid treatment, even at high doses (2.5 mg/kg) before or at the time of vaccination, does not have a significant suppressive effect on the humoral immunity following vaccination. In humans, reversible humoral immune suppression following long-term (years) glucocorticoid therapy has been reported.vii,viii

OPTION: It is reasonable to revaccinate 2 or more weeks after long-term glucocorticoid therapy has ended, especially when treatment occurred during administration of the initial series of core vaccines.

Should vaccine be administered to pets that are receiving immunosuppressive drugs or cytotoxic therapy (other than glucocorticoids) for cats with systemic disease such as cancer or immune-mediated disease?

Vaccines are only recommended for administration to healthy cats. Cats receiving immunosuppressive medications and chemotherapy should not be vaccinated. Doing so may result in a suboptimal immune response. viii

OPTION: Antibody testing for FPV could be utilized to determine the need for administering a booster dose; or, testing could be performed 2 to 4 weeks postvaccination to assess the response of the individual patient following vaccination.

The Task Force recommends using inactivated vaccine if the cat is retroviral positive.

Should I vaccinate immunocompromised cats?

Patients with impaired immune responses, either due to infection with FeLV/FIV or the use of immunosuppressive therapies, are at increased risk of infection and may be candidates for vaccination. Although there is limited feline-specific data, inactivated vaccines are generally regarded as safer in patients with underlying immunosuppression. Retrovirus-infected cats should not be vaccinated against the retrovirus with which they are infected.

PREGNANCY AND VACCINATION

Should a pregnant cat be vaccinated?

If possible, vaccination with attenuated/live vaccines during pregnancy should be avoided to reduce the risk of injury to the fetus. There are exceptions, especially in animal shelters, where vaccination is advised to decrease disease transmission.

RETROVIRUS-INFECTED CATS

What are the recommendations for vaccinating a cat who is infected with FIV or feline leukemia?

The Task Force recommends using inactivated vaccine if the cat is retroviral positive. These cats are at increased risk of infection and may be candidates for vaccination. Although there is limited feline-specific data, inactivated vaccines are generally regarded as safer in patients with underlying immunosuppression. Retrovirus-infected cats should not be vaccinated against the retrovirus with which they are infected.

 

ANESTHESIA AND VACCINATION

Should vaccine be administered to the anesthetized patient?

Doing so is NOT generally recommended. There is a small risk that a postvaccinal hypersensitivity reaction may lead to vomiting and an increased risk of aspiration. However, in the event there is limited opportunity to administer a vaccine to an individual cat (e.g., spay and neuter programs), administering vaccine during or immediately on recovery from anesthesia is acceptable.

BREED-SPECIFIC PROTOCOLS

Are certain purebred cats subject to unique vaccination protocols to assure they are properly immunized?

No. Breed-specific protocols are not deemed necessary today.

Can I vaccinate my hybrid/exotic/wild cat?

Hybrid/exotic/wild cats are thought to include Bengal cats (Asian leopard-cat crosses), Savannah cats (Serval crosses), bobcat or jungle-cat hybrids, wild cat species, or any mix of a wild cat with a domesticated cat. It is not recommended to use any commercial FHV-1, FHV, FPV, FeLV, or rabies vaccine labeled for use in the domesticated cat to vaccinate a hybrid/exotic/wild cat. Generally, hybrid/exotic/wild cats will be considered unvaccinated for rabies regardless of their rabies vaccination status.

TREATING DISEASE WITH VACCINES

Can a vaccine be administered to a cat that is infected (and clinically ill) as a means of “treating” the clinical disease or shortening the course of infection?

Administering FeLV vaccine to clinically-ill patients as a means of treating the disease is neither effective nor recommended. xiii

With upper-respiratory pathogens, intranasal respiratory vaccines may induce nonspecific immunity that offers protection not only against the disease you’re vaccinating for, but also other nontarget pathogens not included in the vaccine. xiv

SHELTER-HOUSED CATS

Regarding recommendations to “vaccinate at time of intake,” how should cats > 18 weeks of age be vaccinated who have been adopted but then are returned back to the shelter once or multiple times?

It is not necessary to administer a vaccine at the time of entry if a history of adequate vaccination can be confirmed.

How does the 2-week minimum vaccination interval recommendation apply to shelter-housed cats?

Cats arriving at shelters are typically vaccinated against FVH-1, FCV, and FPV on intake. If placed within 2 weeks of intake, rabies vaccine is typically administered at the time of release for cats >12 weeks of age. Vaccination against rabies at the time of release is often given even though a prior vaccine event may have taken place within the past 2 weeks. It will be up to the new veterinarian and the new owner to determine if another rabies vaccine should be administered after the two-week interval has passed.

References

iLittle S, Levy J, et. al 2020 AAFP Feline Retrovirus Testing and Management Guidelines. Journal of Feline Medicine and Surgery. 2020: 22, 5-30

iiWilson S, Greenslade J, Saunders G, et al. Difficulties in demonstrating long term immunity in FeLV vaccinated cats due to increasing age-related resistance to infection. BMC Vet Res 2012;8:125.

iiiJirjis FF, Davis T, Lane J, Carritt K et al. Protection Against Feline Leukemia Virus Challenge for at Least Two Years after Vaccination with an Inactivated Feline Leukemia Virus Vaccine. Vet Ther. 2010:11(2): E1-6.

ivWilson S, Greenslade J, Saunders G, et al. Difficulties in demonstrating long term immunity in FeLV vaccinated cats due to increasing age-related resistance to infection. BMC Vet Res 2012;8:125.

vWherry EJ, Teichgraber V, Becker TC, Masopust D, Kaech SM, Antia R, et al. Lineage relationship and protective immunity of memory CD8 T cell subsets. Nat Immunol 2003; 4: 225–234.

viWherry EJ and Ahmed R. Memory CD8 T-cell differentiation during viral infection. J Virol 2004; 78: 5535–5545.

viiLack G, Ochs HD, Gelfand EW. Humoral immunity in steroid-dependent children with asthma and hypogammaglobulinemia. J Pediatrics 1996;129(6):898–903.

viiiFedor ME, Rubinstein A. Effects of long-term low dose corticosteroid therapy on humoral immunity. Ann Allergy Asthma Immunol 2006;97(1):113–6.

ixDay MJ, Horzinek MC, Schultz RD, et al. WSAVA Guidelines for the vaccination of dogs and cats. J Small Anim Pract 2016;57:E1-E45.

xDiGangi, B. A., Levy, J. K., Griffin, B. et al. (2012) Prevalence of serum antibody titers against feline panleukopenia virus, feline herpesvirus 1, and feline calicivirus in cats entering a Florida animal shelter. Journal of the American Veterinary Medical Association 241, 1320-1325

xiJakel, V., Cussler, K., Hanschmann, K. M. et al. (2012) Vaccination against feline panleukopenia: implications from a field study in kittens. BMC Veterinary Research 8, 62

xiiReagan, K.L., Hawley, J.R., Lappin, M.R. Concurrent Administration of an Intranasal Vaccine Containing Feline Herpesvirus-1 (FHV-1) with a Parenteral Vaccine Containing FHV-1 is Superior to Parenteral Vaccination Alone in an Acute FHV-1 Challenge Model. The Veterinary Journal 201, 2014: 202-206.

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xviiHuang, C., Hess, J., Gill, M., Hustead, D. A Dual-Strain Feline Calicivirus Vaccine Stimulates Broader Cross-Neutralization Antibodies Than a Single-strain Vaccine and Lessens Clinical Signs in Vaccinated Cats When Challenged With a Homologous Feline Calicivirus Strain Associated With Virulent Systemic Disease. J Feline Med Surg Feb 2010;12 (2): 129-137.

Boehringer Ingelheim Animal Health USA Inc., Elanco Animal Health, Merck Animal Health, and Zoetis Petcare supported the development of the
2020 AAHA/AAFP Feline Vaccination Guidelines and resources through an educational grant to AAHA.