Peer reViewed Canine Guidelines Key Points for Veterinary Practice

Richard B. Ford, DVM, MS, Diplomate ACVIM & ACVPM(Hon)

n 2011, the Canine Vaccination Task Force, spon- comprised of practicing veterinarians, special- Isored by the American Animal Hospital Associa- ists, academicians, and legal experts, with input tion (AAHA), revised vaccination guidelines for from each of the major manufacturers, dogs.1 created revised canine vaccination guidelines in These canine vaccination guidelines have an 2011.1 Whenever possible, the recommendations immediate impact in private practice, with empha- are based on the most current scientific studies; sis on 3 key areas: recommendations not backed by published studies 1. Developing vaccination protocols are based on unpublished studies, sound immu- 2. Vaccine adverse reactions nologic principles, or expert opinion. 3. Fundamental legal concerns surrounding vac- cine administration. CLASSIFYING Highlighted throughout this article are key The vaccination guidelines separate vaccines into points that represent some of the most important 2 groups: and new recommendations relative to developing • Core: Vaccines that offer protection against and implementing a vaccination protocol. highly contagious, life-threatening or infections that pose a significant threat to DETERMINING PROTOCOLS human health (eg, ). Within the U.S. and Canada, veterinarians who • Noncore: Vaccines that offer protection administer vaccines must select from among a against less serious health threats to dogs or wide variety of proprietary (trade name) products, threats that pose a regional health risk. each of which is backed by technical data defin- Table 1 summarizes core and noncore canine ing safety and efficacy; then promoted through a vaccines as represented in the vaccination guide- robust marketing message. lines. The oral Bordetella bronchiseptica vaccine Interestingly, the ultimate decision regarding was not available at the time the guidelines were selection and use of vaccines is frequently reduced published but is categorized by the author as a to a reasonable assessment of exposure risk and noncore vaccine based on available information.2 determination of product cost. It is not surprising, Remember that the 2011 AAHA Canine therefore, that considerable diversity exists among Vaccination Guidelines are recommendations; companion animal practices regarding vaccine they are not requirements. It is ultimately the deci- administration. sion of the individual veterinarian or practice to To facilitate implementation of rational vaccina- establish which vaccines in a protocol are desig- tion protocols in individual practices, a task force nated core or noncore.

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CORE VACCINES confer immediate against rabies. In Vaccines designated as core should be administered most states, a dog is not legally immunized to all dogs. The AAHA Canine Vaccination Task Force against rabies until 28 days following initial vac- defines the following vaccines as core: cination.8 • Distemper virus (CDV) • Rabies vaccination requirements for dogs vary • Parvovirus (CPV) significantly among states: In some states, rabies • Adenovirus-2 (CAV-2) vaccination for dogs is not specifically required. • Rabies (RV). Within these states, however, a local (city or coun- ty) rabies vaccination ordinance may be in effect. Initial Vaccination of Young Dogs • Where no state or local ordinance exists, vet- Vaccination Other Than Rabies erinarians are encouraged to recommend rabies Current recommendations for initial vaccination vaccination in accordance with guidelines from of young dogs stipulate that, with the exception of the National Association of State rabies, 3 doses of a combination core vaccine be Veterinarians;8 a suggested protocol is outlined in administered between 6 and 16 weeks of age. In Table 2. practice, a single combination dose is typically recom- mended for administration at 2, 3, and 4 months of age (Table 2). KEY POINT: in most states, a dog is not Dosing Interval. Today, most manufacturers offer legally immunized against rabies until 28 days combination core vaccines with the recommendation following initial vaccination. to administer 2 doses by 12 weeks of age.3 The guide- lines, however, emphasize the importance of adminis- tering a third dose (or the final dose) between 14 and Revaccination Intervals in Adult Dogs 16 weeks of age. This recommendation is based on Revaccination Other Than Rabies observations that, in some dogs, the level of maternally A single dose of combined core vaccines (CDV/ derived antibody may be sufficiently high to interfere CPV/CAV-2) should be administered within 1 with vaccines administered at 12 weeks of age, par- year of initial core vaccination, regardless of the ticularly CPV. product used.1 This recommendation ensures that a Recombinant Technology. The recombinant canine patient receives core vaccines at an age when maxi- distemper virus (rCDV) vaccine can be used inter- mum (protective) response to the antigens can be changeably with the modified-live expected. virus (MLV CDV) vaccine in practice. Characteristics With the exception of , adult dogs unique to recombinant technology have been should be revaccinated with a single dose of core addressed in the guidelines: vaccines (CDV/CPV/CAV-2) every 3 years or longer, • The rCDV vaccine is incapable of replicating in regardless of the product used.1 This recommenda- dogs and, therefore, reversion to a virulent CDV tion highlights 2 principal facts: is not possible.1 1. The duration of protective immunity conferred • In addition, the rCDV vaccine uniquely immu- by administration of core vaccines in adult dogs nizes young dogs as much as 2 weeks earlier than extends at least 5 years, and probably longer.2,9-14 conventional MLV CDV vaccines.4-7 For this reason, 2. With the exception of rabies vaccination, veteri- rCDV vaccination may have significant advantages narians have considerable latitude in recommend- over MLV vaccination in young dogs at risk for ing vaccination booster intervals.1 exposure to CDV. While vaccine manufacturers may recommend administration of “annual boosters” for adult dogs, the recommendation does not constitute a legal mandate KEY POINT: Regardless of the product to do so. Most manufacturers include minimum dura- used, all dogs should receive a final dose tion of immunity data on product package inserts, of the initial series of core vaccines (CdV/CPV/ which meets or exceeds 3 years.3 CaV-2) between 14 and 16 weeks of age.

KEY POINT: Regardless of the product used, Rabies Vaccination a single dose of core vaccines (CdV/CPV/ The first dose of rabies vaccine should be admin- CaV-2) should be administered within 1 year istered in accordance with state or local statute. of initial core vaccination; thereafter, the • Within the U.S., rabies vaccination should not recommended interval for revaccination of adult occur in any dog (or cat) less than 3 months of dogs with core vaccines is every 3 years or age.3 longer. • Initial vaccination is generally not regarded to

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Table 2. summary reCommendaTions for VaCCinaTion of doGs Vaccine Initial Vaccination Revaccination CORE VACCINES Distemper (MLV or r) + • Administer 3 doses between 6 and 16 • Administer a single dose no later Parvovirus (MLV) + weeks of age. than 1 year following the last dose Adenovirus-2 (MLV) • Single dose at 8, 12, and 16 weeks of age in the initial series; then, every 3 is commonly recommended. years or longer thereafter. Option: although parainfluenza virus vaccine is commonly administered parenterally in combination with the above vaccines (da2PP), parainfluenza has been classified as a noncore vaccine (see below). Rabies (killed) • Single dose usually given at 12 or 16 • Administer a single dose of vaccine weeks of age (local/state statutes apply). within 12 months (a 3-year rabies vaccine may be administered at this time); then every 3 years there- after or as required by law. • In the U.S., all states now recog- nize 3-year labeled rabies vac- cines. NONCORE VACCINES Intranasal • Administer a single dose (intranasal only) • Where risk of exposure is sus- B bronchiseptica (AvLB) at 12 or 16 weeks of age (some authors tained, administer a single dose recommend a dose at 12 and 16 weeks). annually. May be combined with: • Maternal antibody interference is not a • Parainfluenza virus factor for vaccines administered intrana- (MLV) or sally; manufacturers may recommend ini- • Parainfluenza virus + tial vaccination as early as 3 or 4 weeks Adenovirus-2 (MLV) of age. Parenteral • Administer 2 doses, 2 to 4 weeks apart, • Annual booster recommended by B bronchiseptica (KB) regardless of age. manufacturer (duration of immu- nity data has not been published). Oral • Administer a single dose into the buccal • Administer a single dose into the B bronchiseptica (AvLB) pouch as early as 8 weeks of age. buccal pouch annually. (KB) • Administer 2 initial doses, 2 to 4 weeks • Where risk of exposure exists, 4-serovar apart; do noT administer the first dose administer a single dose annually. prior to 12 weeks of age. Administration of 2-way vaccine is currently NOT Note: In small breed dogs, delay initial dose recommended until after completion of initial CORE series. • Administer 2 initial doses, 2 to 4 weeks • Where risk of exposure exists, (recombinant OspA or KB) apart; do noT administer first dose prior administer a single dose annu- to 12 weeks of age unless risk of expo- ally. sure is high.

Note: In small breed dogs, consider delay- ing initial dose until after completion of initial CORE series. Canine influenza virus • Administer 2 initial doses, 2 to 4 weeks • Manufacturer recommends (killed) apart. annual revaccination where risk of exposure exists. • Duration of immunity has not been established. Crotalus atrox () is conditionally licensed to aid in prevention of signs following envenomation by Western diamondback rattlesnake. Canine coronavirus vaccine is noT recommended. avlb = avirulent live bacteria; Kb = killed bacterins; mlV = modified-live virus; r = recombinant

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Rabies Revaccination Where rabies revaccination is required for dogs, KEY POINT: The revaccination interval for a single dose is typically required within 1 year noncore vaccines is every 12 months as long following the initial dose, regardless of the dog’s as a reasonable risk for exists; there age when the initial dose was administered.8 are no extended interval recommendations. Generally, a dog that is not revaccinated within 1 year following the initial dose is legally not immunized. In most states, the second dose of rabies vaccine in Not Recommended the initial 2-dose series may be labeled as a 1- or 3-year The AAHA Canine Vaccination Task Force recom- rabies vaccine; the duration of immunity following mends NOT using either the killed or MLV canine administration is contingent on this product labeling. coronavirus (CCoV) vaccine. This designation is not In some states, however, local statutes may impose based on safety issues pertaining to any licensed requirements that are stricter than state requirements product; instead, it is based on the facts that (1) dogs (eg, annual rabies vaccination). Veterinarians should derive limited to no protective immunity from the vac- be familiar with local rabies require- cine and (2) CCoV does not cause significant disease. ments for dogs. However, CCoV vaccines are licensed by the USDA and may be administered at the discretion of the indi- NONCORE VACCINES vidual veterinarian. Vaccines designated as noncore, or optional, are those that a veterinarian may recommend for individual VACCINE ADVERSE REACTIONS patients in the event there is reasonable risk for expo- A vaccine adverse reaction (or adverse event) refers to sure to the infectious virus or bacteria. Unfortunately, any undesirable, or unintended, effect associated with comprehensive guidance on which locations pose the the administration of vaccines, including failure to highest risk for exposure to specific pathogens is not immunize. Unfortunately, vaccine adverse reactions in available. Therefore, the decision whether to admin- veterinary medicine are significantly underreported, ister a particular noncore vaccine is left to the vet- making it impossible to determine actual adverse erinarian. Such decisions should be based on known event rates. However, considering the number of vac- geographical risk for exposure to a pathogen combined cines administered yearly, it is generally agreed that with knowledge of lifestyle factors unique to the indi- adverse reactions are relatively uncommon in dogs. vidual dog. Table 1 lists noncore vaccines for dogs. Despite lack of data, certain risk factors have been identified. The guidelines include recommendations on: Initial Vaccination • Mitigating risk With the exception of vaccines licensed for intra- • Treatment of acute-onset reactions nasal administration to dogs (eg, those contain- • Revaccination of patient with known or suspected ing Bordetella bronchiseptica avirulent live bac- history. teria) and the oral B bronchiseptica vaccine, all noncore vaccines require at least 2 initial doses, Adverse Reactions administered 2 to 4 weeks apart, to immunize. Because vaccines are biologically active products A single dose of a parenterally administered noncore and potent immunostimulants, minor reactions can vaccine is not expected to induce a protective immune be expected in any dog. Common adverse reactions response. If a dog is presented for the second dose 6 reported to manufacturers include: weeks or longer after the initial dose, it is generally • Postvaccinal lethargy recommended to repeat the initial series by administer- • Pain (discomfort) ing 2 additional doses, 2 to 4 weeks apart. • Inappetance • Lumps at the injection site. Owners should be advised to anticipate minor reac- KEY POINT: regardless of a dog’s age or tions such as these for 1 to 2 days after vaccination. the vaccines used, the minimum administra- Advise clients to contact the practice if the following tion interval for noncore vaccines is 2 weeks. signs develop: vomiting, diarrhea, seizures, difficulty breathing or rapid respirations, facial swelling, or col- lapse. If a patient’s condition worsens or shows no Adult Revaccination improvement within 48 hours, follow-up examination Following completion of the initial 2-dose series of a is recommended. noncore vaccine, and assuming a reasonable risk for exposure is sustained, annual revaccination with the Revaccination & At-Risk Patients appropriate noncore vaccine is recommended. There In general, revaccination of patients with a known or are no recommendations for intervals extending suspected history of a serious adverse vaccine reaction beyond 1 year for noncore vaccines. is not recommended.

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In addition, patients with prior diagnosis of informed consent, and medical record documen- immune-mediated disorders (eg, immune-mediated tation are discussed in detail. hemolytic anemia, thrombocytopenia) should prob- • Although the guidelines may differ from state- ably not receive additional vaccines due to the belief ments on product labels, veterinarians practicing that vaccine administration may reactivate the disor- in the U.S. and Canada do have considerable dis- ders; however, this concern has not been validated in cretion in the selection and use of vaccines; rabies scientific studies. vaccination is an obvious exception. In these patients, determining the antibody titer • Adopting recommendations outlined in the of the core vaccines (especially CDV and CPV) will guidelines is consistent with scientific principles provide reliable information on the individual’s of immunization and good medical practice. immune status. Several states give veterinarians the • As highlighted in the guidelines, practitioners authority to exempt rabies vaccination in patients that must determine the vaccination protocols that have a diagnosed illness or a prior history of a vaccine best suit their practices and level of risk tolerance. adverse event. However, if a patient is exempted from While all USDA-licensed vaccines, regardless of rabies vaccination, it is important to inform the client minimum or maximum duration of immunity, have a that, if the dog bites someone, it will be treated as a package insert that says, “annual revaccination recom- nonvaccinated dog. mended,” this statement does not imply that annual revaccination is necessary to maintain immunity. Small Breed Dogs For the first time, the guidelines have addressed admin- istering vaccines to small breed dogs (≤ 20 pounds KEY POINT: With the exception of rabies vac- at the estimated adult weight). Published studies and cine, veterinarians have considerable ability to practitioner experience support the fact that small use biologics (vaccines) in a discretionary manner. breed dogs may have increased risk of experiencing vaccine adverse reactions, especially when multiple vaccines are administered at the same time.15-18 Client Discussions It is now recommended that, in small breed dogs of Discussing potential risks associated with vaccine all ages, noncore vaccines be administered 2 or more administration with clients is not inherently different weeks after core vaccine administration.1 While this than discussing the risks of a medical procedure or recommendation requires additional appointments, treatment. reports from veterinarians indicate that owner compli- • During an initial vaccine appointment, a thor- ance is high, particularly when owners are told that the ough discussion of potential adverse reactions reason for additional visits is patient safety. should be presented and documented in the medical record. On subsequent vaccination visits, a less extensive discussion is appropriate. KEY POINT: To mitigate the risk of adverse • If a veterinarian believes significant health risks reactions in small breed dogs, administer may be associated with vaccine administration to noncore vaccines at least 2 weeks or longer an individual patient and elects to recommend after administration of core vaccines. against vaccination, the reasons for the recom- mendation should be discussed with the client and clearly noted in the medical record.1 VACCINATION LIABILITY • In some states/municipalities, veterinarians may Veterinarians are concerned about potential liabil- not have the option to recommend against rabies ity associated with following recommendations other vaccination, regardless of the patient’s health sta- than those from the manufacturer. For example, is tus or perceived risk for an adverse reaction. a veterinarian legally liable if a dog, not vaccinated annually in accordance with manufacturer label rec- COMING UP ommendations, develops an infection preventable In the upcoming November/December issue of Today’s by vaccine (eg, CDV) after revaccination at a 3-year Veterinary Practice, the 2012 AAFP interval? Guidelines will be reviewed. The January/February 2013 issue will present the first article in our new Legal Considerations vaccination column, which will address vaccination The reader is encouraged to review the Legal concerns raised by practicing veterinarians. ■ Considerations section of the 2011 AAHA Canine Vaccination Guidelines.1 CaV-2 = adenovirus-2; CdV = distemper virus; • Critical information concerning professional dis- CCoV = coronavirus; CPV = parvovirus; mlV = modified-live virus; mlV CdV = modified-live cretion in use of vaccines, medical negligence canine distemper virus; rCdV = recombinant canine related to vaccine administration, consent versus distemper virus; rV = rabies

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References 15. roth Ja. Mechanistic bases for adverse vaccine reactions and vaccine 1. welborn lV, deVries JG, Ford rB, et al. 2011 AAHA Canine failures. Adv Vet Med 1999; 41:681-700. Vaccination Guidelines. available at aahanet.org; accessed July 6, 16. Frana ts, elsken la, Karli sa. summary of adverse event reports for 2012. veterinary biologic products received by the usda from 1999 through 2. Hess tJ, Parker ds, Hassal aJ, Chaing Y. evaluation of efficacy of oral 2005. JAVMA 2006; 229(7):1100-1102. administration of Bordetella bronchiseptica intranasal vaccine when 17. Meyer eK. Vaccine-associated adverse events. Vet Clin N Am Small used to protect puppies from tracheobronchitis due to B bronchiseptica Anim Prac 2001; 31:493-514. infection. Intern J Appl Res Vet Med 2009; 9(3):300-305. 18. Moore Ge, Guptill lF, ward MP, et al. adverse events diagnosed 3. Manufacturers’ product labels. within three days of vaccine administration in dogs. JAVMA 2005; 4. Pardo MC, Bauman Je, Mackowiak M. Protection of dogs against 227(7):1102-1108. canine distemper by vaccination with a canarypox virus recombinant expressing canine distemper virus fusion and hemagglutinin glycoproteins. Am J Vet Res 1997; 58(8):833-836. 5. Hageny tl, Haase CJ, larson lJ, et al. a comparison between Richard B. Ford, DVM, recombinant, naked dna and modified live canine distemper virus MS, Diplomate ACVIM & (CdV) vaccines. Conference of Workers in Animal Disease 2004; ACVPM(Hon), is Emeritus poster presentation abstract 65. 6. larson l, schultz rd. effect of vaccination with rCdV vaccine Professor of Medicine immediately before exposure under shelter-like conditions. Vet Ther at North Carolina State 2006; 7(2):113-118. University’s College of 7. Pardo MC, tanner P, Bauman J, et al. immunization of puppies in the Veterinary Medicine. He is presence of maternally derived antibodies against canine distemper virus. J Comp Pathol 2007; 137:s72-s75. a retired Brigadier General 8. Compendium of animal rabies prevention and control, 2011. national from the USAF Reserve, association of state Public Health Veterinarians, inc. MMWR 2011; where he was assigned to the Office of the 60(6):1-20. 9. schultz rd, thiel B, Mukhtar e, et al. age and long-term protective Surgeon General at the Pentagon. Dr. Ford is immunity in dogs and cats. J Comp Pathol 2010; 142:s102-s108. also a past president of the NAVC Conference 10. larson lJ, sawchuck s, schultz rd. duration of vaccinal immunity in and continues his role as a member of the sci- a population of clinic dogs. Conference of Research Workers in Animal entific program committee. His clinical interests Disease 2002; abstract 75P. 11. schultz rd. duration of immunity for canine and feline vaccines: a are in the field of companion animal infectious review. Vet Microbiol 2006; 117(1):75-79. disease; he is a prolific author and serves on 12. Gill M, srinivas J, Morozov i, et al. three-year duration of immunity for both the AAHA Canine Vaccination Task Force canine distemper, adenovirus, and parvovirus after vaccination with a multivalent canine vaccine. J Appl Res Vet Med 2004; 2(4):227-234. and AAFP Feline Vaccination Advisory Panel. Dr. 13. larson lJ, schultz rd. three-year duration of immunity in dogs Ford received his DVM from Ohio State University vaccinated with a canarypox-vectored recombinant canine distemper and completed an internal medicine residency virus vaccine. Vet Ther 2007; 8(2):101-106. at Michigan State University. He held a previous 14. larson lJ, schultz rd. three-year serologic immunity against canine parvovirus type 2 and canine adenovirus type 2 in dogs vaccinated faculty position at Purdue University. with a canine combination vaccine. Vet Ther 2007; 8(4):305-310.

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