An animal can be considered immunized within 28 days after initial vaccination, when a peak rabies virus antibody titer is reached. An animal is considered currently vaccinated and immunized if the initial vaccination was administered at least 28 days previously or booster vaccinations have been administered in accordance with recommendations. Because a rapid anamnestic response is expected, an animal is considered currently vaccinated immediately after a booster vaccination. Show
Vaccination schedulesVaccination of dogs, ferrets, and livestock can be started at no sooner than three months of age. Some cat vaccines can be given as early as two months of age. Regardless of the age of the animal at initial vaccination, a booster vaccination should be administered one year later. Dogs, Cats, and FerretsAll dogs, cats, and ferrets should be vaccinated and revaccinated against rabies according to product label directions. If a previously vaccinated animal is overdue for a booster, it should be revaccinated. Immediately following the booster, the animal is considered currently vaccinated and should be placed on a vaccination schedule according to the labeled duration of the vaccine used. LivestockConsideration should be given to vaccinating livestock that are particularly valuable. Animals that have frequent contact with humans (e.g., in petting zoos, fairs, and other public exhibitions) and horses traveling interstate should be currently vaccinated against rabies. Confined AnimalsWildNo parenteral rabies vaccines are licensed for use in wild animals or hybrids (i.e., the offspring of wild animals crossbred to domestic animals). The AVMA has recommended that wild animals or hybrids should not be kept as pets (14–17). Maintained in Exhibits and in Zoological ParksCaptive mammals that are not completely excluded from all contact with rabies vectors can become infected. Moreover, wild animals might be incubating rabies when initially captured; therefore, wild-caught animals susceptible to rabies should be quarantined for a minimum of 6 months. Employees who work with animals at exhibits and in zoological parks should receive preexposure rabies vaccination. The use of pre- or postexposure rabies vaccinations for handlers who work with animals at such facilities might reduce the need for euthanasia of captive animals that expose handlers. Carnivores and bats should be housed in a manner that precludes direct contact with the public (12). Serologic titersTiters do not directly correlate with protection because other immunologic factors also play a role in preventing rabies, and the ability to measure and interpret those other factors are not well developed. Therefore, evidence of circulating rabies virus antibodies should not be used as a substitute for current vaccination in managing rabies exposures or determining the need for booster vaccinations in animals. Interstate travelBefore interstate movement (including commonwealths and territories), dogs, cats, ferrets, and horses should be currently vaccinated against rabies. Animals in transit should be accompanied by a valid NASPHV form 51 pdf icon[PDF 13 KB] , Rabies Vaccination Certificate. When an interstate health certificate or certificate of veterinary inspection is required, it should contain the same rabies vaccination information as Form 51. Richard B. FordDVM, MS, Diplomate ACVIM & ACVPM (Hon) Richard B. Ford, DVM, MS, Diplomate ACVIM & ACVPM (Hon), is Emeritus Professor of Medicine at North Carolina State University’s College of Veterinary Medicine. He is a retired Brigadier General from the USAF Reserve, where he was assigned to the Office of the Surgeon General at the Pentagon. Dr. Ford is also a past president of the NAVC Conference and continues his role as a member of the scientific program committee. His clinical interests are in the field of companion animal infectious disease; he is a prolific author and serves on both the AAHA Canine Vaccination Task Force and AAFP Feline Vaccination Advisory Panel. Dr. Ford received his DVM from Ohio State University and completed an internal medicine residency at Michigan State University. He held a previous faculty position at Purdue University. Read Articles Written by Richard B. Ford Published vaccination guidelines for dogs and cats enable the clinician to implement vaccination protocols tailored for individual patients that provide protective immunity at the appropriate stages of life.1,2 However, protocols used in practice generally assume owner compliance with the recommended, ideal vaccination schedule. In reality, clientele don’t always, or aren’t able to, adhere to the “ideal.” Editor’s Note: This article was originally published in November/December 2012. Please use this content for reference or educational purposes, but note that it is not being actively vetted after publication. For the most recent peer-reviewed content, see our issue archive. This article addresses options for immunizing dogs and cats significantly overdue for scheduled vaccine appointments. Remember, however, that recommendations outlined are based largely on expert opinion; published scientific studies on revaccination requirements for overdue patients are limited. In addition, a multitude of intrinsic (eg, age, genetics, maternally derived antibody) and extrinsic (eg, vaccine type, number of previous vaccine doses, time since last dose was administered, risk for exposure) factors impact an individual patient’s immunity and need for additional vaccine doses. Therefore, it is ultimately the decision of the individual clinician to determine what vaccines and how many doses should be recommended. Conventional RecommendationsCore VaccinesCore vaccines—those that should be administered to all dogs and cats—are listed in Table 1. Initial Vaccination
The author’s opinion is that a maximum 6-week interval between doses can be applied to both dogs and cats without jeopardizing immunologic outcome. Discussions with veterinarians who follow published vaccination guidelines indicate that many practices recommend administering core vaccines at 2, 3, and 4 months of age in both dogs and cats. Revaccination Although all states currently recognize the 3-year rabies vaccines, local (city/county) requirements may mandate annual revaccination against rabies for dogs and cats. With the exception of rabies, the decision to revaccinate a dog or cat annually versus triennially is left to the discretion of the clinician. Noncore VaccinesNoncore—optional—vaccines are listed in Table 1.
Initial Vaccination
Revaccination
Overdue-For-Vaccination RecommendationsIn the event a pet owner does not, or is not able to, adhere to the conventional vaccination schedules outlined, the following recommendations provide reasonable, alternative schedules that offer the most appropriate vaccines at the most appropriate intervals. Overdue During Initial Vaccination SeriesFor the juvenile (< 16 weeks of age) dog and cat, the initial vaccination series with core vaccines is critical. During this series, a dog or cat can be considered overdue for vaccination if the patient is not returned within 6 weeks following administration of the previous dose. However, there are no published studies defining the specific intervals between initial doses of vaccine required to assure a protective immune response. It is reasonable to recommend an alternative vaccination schedule for a dog or cat determined to be overdue. Deciding which vaccine should be administered and when is based on 2 factors:
Attenuated Vaccines + Recombinant CDV Vaccine The challenge is determining when MDA levels no longer interfere with immunization in the individual patient. In most dogs and cats, MDA is expected to decline to noninterfering levels by 16 weeks of age. Common scenarios include:
Inactivated Vaccines + Recombinant Noncore Vaccines
The interval between the first (priming) and second (immunizing) doses of an inactivated vaccine is important: If the interval between the initial 2 doses is inordinately prolonged, the anamnestic response to the second dose may be significantly diminished, leaving the patient susceptible if exposed. During the initial series, using a noncore vaccine, any patient with a vaccination interval that exceeds 6 weeks between doses should receive 2 additional doses, 2 to 6 weeks apart. Common examples include:
See Tables 2 and 3 for a summary of recommendations for puppies and kittens overdue for vaccination during initial (juvenile) series.
Overdue for Adult RevaccinationWhen considering an alternative vaccination schedule for adult dogs and cats overdue for a vaccine dose, the same principles for a patient overdue during the initial series apply: the elapsed time since the previous vaccine and type of vaccine (recombinant, attenuated, or inactivated) must be considered. Core VaccinesDogs or cats can be considered overdue for revaccination with core vaccines if the last dose was administered over 3 years ago. With the exception of the 1-year rabies vaccine, this recommendation applies to all core vaccines regardless of manufacturer. Because most core vaccines currently recommended are attenuated (or recombinant CDV), a single dose of a combination vaccine is expected to induce a protective immune response in a patient regardless of the number of years since the previous dose. Noncore VaccinesRecommendations for adult dogs overdue for an inactivated noncore vaccine vary somewhat depending on the antigen. Killed bacterial vaccines (bacterins), for example, tend to have a shorter duration of immunity and shorter immune memory compared to killed viral vaccines. Bacterial vaccines. Generally, an adult dog or cat is considered overdue for an inactivated noncore bacterin (eg, leptospirosis, Chlamydophila felis) if the last dose was administered 2 or more years previously. These patients should receive 2 doses, 2 to 6 weeks apart, to reinstate protective immunity. Viral vaccines. Because the immunizing antigen is an inactivated virus as opposed to bacteria, a single dose of vaccine is expected to boost immunity in a patient that has received a dose within the past 3 years (although there are no published studies to confirm this). However, dogs and cats overdue for noncore viral vaccines by 2 or more years should receive 2 doses, 2 to 6 weeks apart. See Tables 4 and 5 for a summary of recommendations for adult dogs and cats that are considered overdue for revaccination.
Overdue for Rabies VaccinationAlthough rabies vaccination of dogs or cats is not required by all states or provinces, current vaccination guidelines recommend rabies vaccine as core for dogs and cats. This recommendation is based on the facts that:
Veterinarians seeking legal guidance from a state or province on revaccination of dogs and cats overdue for rabies inoculation may have difficulty finding specific recommendations. When guidance is provided, recommendations may vary from state to state, as well as from city to city within a state. Veterinarians are encouraged to review applicable rabies vaccination laws, if available, before recommending alternative schedules for overdue patients. In locations where specific guidance on vaccination of overdue dogs and cats is not published, it is appropriate to contact local or state authorities responsible for providing oversight on animal rabies prior to implementing a novel rabies vaccination schedule. For example, the Pennsylvania Department of Agriculture employs veterinarians within the Bureau of Animal Health who can review a proposed vaccination schedule and circumstances surrounding the case. It should be noted that the following recommendations are applicable only in those locations that do not provide specific guidance to veterinarians on revaccination of dogs and cats overdue for rabies inoculation. Initial Vaccination
Revaccination
Generally, the anamnestic response in a previously vaccinated animal is considered to be rapid and protective. A dog or cat is immediately considered vaccinated (protected) following administration of a booster dose.3,8 Vaccination
for Overdue Pets
Sustained immune memory in a pet that has previously been vaccinated against rabies is a significant factor in making recommendations for revaccination of overdue dogs and cats. The ability of a single dose to rapidly induce a significant (protective) anamnestic response justifies the recommendation to administer a single dose to an overdue patient. However, there are no studies that stipulate how many years a dog or cat may be overdue for a rabies inoculation and still receive immunologic protection if given a single dose. For example:
References
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