ALL ABOUT VACCINE ISSUES and VACCINATIONS*
W. Jean Dodds, DVM 1 and Ronald D. Schultz, PhD 2
There is little doubt that application of modern vaccine technology has permitted us to protect companion animals effectively against serious infectious diseases. Today, we can question conventional vaccine regimens and adopt effective and safe alternatives primarily because the risk of disease has been significantly reduced by the widespread use of vaccination programs, which convey underlying population or herd immunity.
For many veterinary practitioners canine vaccination programs have been “practice management tools” rather than medical procedures. Thus, it is not surprising that attempts to change the vaccines and vaccination programs based on scientific information have created significant controversy. A “more is better” philosophy still prevails with regard to pet vaccines.
Annual vaccination has been and remains the single most important reason why most pet owners bring their pets for an annual or more often “wellness visit.” Another reason for the reluctance to change current vaccination programs is many practitioners really don’t understand the principles of vaccinal immunity. Clearly, the accumulated evidence indicates that vaccination protocols should no longer be considered as a “one size fits all” program.
Giving annual boosters when they are not necessary has the client paying for a service which is likely to be of little benefit to the pet’s existing level of protection against these infectious diseases. It also increases the risk of adverse reactions from the repeated exposure to foreign substances.
So, have veterinarians really embraced the national policies on vaccination guidelines from the American Animal Hospital Association, American Veterinary Medical Association and Academy of Feline Practitioners? Does the public trust veterinarians to be up-to-date on these issues or are they unsure? Do they believe veterinarians have a conflict of interest if they seek the income from annual booster vaccinations? Given current media attention to vaccination issues, the public is more aware and worried about vaccine safety.
Some veterinarians today still tell their clients there is no scientific evidence linking vaccinations with adverse effects and serious illness. This is ignorance, and confuses an impressionable client. On the other hand, vaccine zealots abound with hysteria and misinformation. None of these polarized views is helpful.
Further, veterinarians are still routinely vaccinating ill dogs and those with chronic diseases or prior adverse vaccine reactions. This is especially problematic for rabies boosters, as many colleagues believe they have no legal alternative, even though the product label states it's intended for healthy animals. For more information, see www.rabieschallengefund.org
Alternatives to Current Vaccine Practices
1) measuring serum antibody titers;
2) avoidance of unnecessary vaccines or over vaccinating;
3) caution in vaccinating sick or febrile individuals; and
4) tailoring a specific minimal vaccination protocol for dogs of breeds or families known to be at increased risk for adverse reactions.
5) considerations include starting the vaccination series later, such as at nine or ten weeks of age when the immune system is better able to handle antigenic challenge;
6) alerting the caregiver to pay particular attention to the puppy’s behavior and overall health after the second or subsequent boosters; and
7) avoiding revaccination of individuals already experiencing a significant adverse event. Littermates of affected puppies should be closely monitored after receiving additional vaccines in a puppy series, as they too are at higher risk.
Some Frequently Asked Questions – Some questions are part of the Guidelines for Vaccination of Dogs and Cats compiled by the Vaccine Guidelines Group (VGG) of the World Small Animal Veterinary Association (WSAVA)
Q. Do dogs competing in agility or other events need more vaccines for protection than other pet dogs?
A. No, although if the event location has an exposure risk for Leptospirosis or Lyme disease , annual vaccination for these diseases should be considered.
Q. Is there risk of overvaccinating with vaccines not needed for a specific animal?
A. Yes. Vaccines contain material designed to challenge the immune system of the pet, and so can cause adverse reactions. They should not be given needlessly, and should be tailered to the pet’s individual needs.
Q. Are the initial series of puppy core vaccines immunosuppressive?
A. Yes. This period of immunosuppression from MLV canine distemper and hepatitis vaccines coincides with the time of vaccine-induced viremia, from days 3 to 10 after vaccination.
Q. Can anesthetized patients be vaccinated?
A. This is not preferred, because a hypersensitivity reaction with vomiting and aspiration could occur and anesthetic agents can be immunomodulating.
Q. Is it safe to vaccinate pregnant pets?
A. Absolutely not.
Q. Should pets with immunosuppressive diseases such as cancer or autoimmune diseases, or adverse vaccine reactions/ hypersensitibvity receive booster vaccinations?
A. No. Vaccination with MLV products should be avoided as the vaccine virus may cause disease; vaccination with killed products may aggravate the immune-mediated disease or be ineffective. For rabies boosters that are due, local authorities may accept titers instead or accept a letter from your veterinarian.
Q. If an animal receives immunosuppressive therapy, how long afterwards can the pet safely be vaccinated?
A. Wait at least 2 weeks.
Q. Should vaccines be given more often than 2 weeks apart even if a different vaccine is being given?
A. No. The safest and most effective interval is 3-4 weeks apart.
Q. At what age should the last vaccine dose be given in the puppy series?
A. The last dose of vaccine should be given between 14-16 weeks regardless of the number of doses given prior to this age. Rabies vaccine should preferably be given separately as late as possible under the law (e.g. 16-24 weeks).
Q. Should the new canine influenza vaccine be given routinely?
A. No. It is intended primarily for pounds and shelters and high density boarding facilities, as nose-to-nose contact and crowding promote viral transmission.
Q. Can intranasal Bordetella vaccine be given parenterally (injected)?
A. No. The vaccine can cause a severe local reaction and may even kill the pet.
Q. Will a killed parenteral Bordetella vaccine given intranasally produce immunity?
A. No.
Q. Are homeopathic nosodes capable of immunizing pets?
A. No. There is no scientific documentation that nosodes protect against infectious diseases of pets. The one parvovirus nosode trial conducted years ago did not protect against challenge.
Q. Should disinfectant be used at the vaccine injection site?
A. No. Disinfectants could inactivate a MLV product.
Q. Can vaccines cause autoimmune diseases?
A. Vaccines themselves do not cause these diseases, but they can trigger autoimmune responses followed by disease in genetically predisposed animals, as can any infection, drug, or chemical / toxic exposures etc.
Q. Can a single vaccine dose provide any benefit to the dog? Will it benefit the canine population?
A. Yes. One dose of a MLV canine core vaccine should provide long term immunity when given to animals at or after 16 weeks of age. Every puppy 16 weeks of age or older should receive at least one dose of the MLV core vaccines. We need to vaccinate more animals in the population with core vaccines to achieve herd immunity and thereby prevent epidemic outbreaks.
Q. If an animal receives only the first dose of a vaccine that needs two doses to immunize, will it have immunity?
A. No. A single dose of a two-dose vaccine like Leptospirosis vaccine will not provide immunity. The first dose is for priming the immune system. The second for boosting the immunity has to be given within 6 weeks; otherwise the series has to start over again. After those two doses, revaccination with a single dose can be done at any time.
Q. Can maternally derived antibodies (MDA) also block immunity to killed vaccines and prevent active immunization with MLV vaccines?
A. Yes. MDA can block certain killed vaccines, especially those that require two doses to immunize. With MLV vaccines, two doses are often recommended, particularly in young animals, to be sure one is given beyond the neutralizing period of MDA.
Q. How long after vaccination does an animal develop immunity that will prevent severe disease when the core vaccines are used?
A. This is dependent on the animal, the vaccine, and the disease.
· The fastest immunity is provided by canine distemper virus (CDV) vaccines -- MLV and recombinant canarypox virus vectored. The immune response starts within mins - hrs and provides protection within a day without interference from MDA.
· Immunity to canine parvovirus (CPV-2) develops after 3-5 days when an effective MLV vaccine is used.
· Canine adenovirus-2/hepatitis (CAV-2) MLV given parenterally provides immunity against CAV-1 in 5 to 7 days.
Q. Can dogs be “non-responders” and fail to develop an immune response to vaccines?
A. Yes. This is a genetic characteristic seen particularly in some breeds or dog families. Boosting them regularly will not produce measurable antibody. Some of these animals may be protected against disease by their cell-mediated and secretory immunity.
Q. Are there parvovirus and distemper virus field mutants that are not adequately protected by current MLV vaccines?
A. No. All the current CPV-2 and CDV vaccines provide protection from all known viral isolates, when tested experimentally as well as in the field. The current CPV-2 and CPV-2b vaccines provide both short and long term protection from challenge by the CPV-2c variant.
Q. Are serum antibody titres useful in determining vaccine immunity?
A. Yes. They are especially useful for CDV, CPV-2 and CAV-1 in the dog, FPV in the cat, and rabies virus in the cat and dog. Rabies titers, however, are often not acceptable to exempt individual animals from mandated rabies boosters in spite of medical justifcation. Serum antibody titers are of limited or no value for (many of) the other vaccines.
1 President, Hemopet, 938 Stanford Street, Santa Monica, CA 90403;2 Chairman, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706.
* Excerpted from: AKC Health Foundation, St. Louis, MO, 2007; J Sm An Pract 48, 528–541, 2007; 5th IVVDC Conference , Madison, WI , 2009.
Additional Literature
● Day MJ, Horzinek MC, Schultz RD. Guidelines for the vaccination of dogs and cats. J Sm An Pract, 48, 528-541 2007
● Dodds WJ. Vaccination protocols for dogs predisposed to vaccine reactions. J Am An Hosp Assoc 38: 1-4, 2001.
● Dodds WJ. Vaccine issues revisited: what’s really happening ? Proc Am Hol Vet Med Assoc, Tulsa, OK, 2007, pp 132-140.
● Paul MA (chair) et al. Report of the AAHA Canine Vaccine Task Force : 2006 AAHA Canine Vaccine Guidelines. J Am An Hosp Assoc 42:80-109, Mar-April 2006, 28 pp. www.aahanet.org
● Schultz R D Considerations in designing effective and safe vaccination programs for dogs. In: Carmichael LE (editor), Recent Advances in Canine Infectious Diseases. Intern Vet Inform Serv, 2000. www.ivis.org.
● Schultz RD. Duration of immunity for canine and feline vaccines: a review. Vet Microbiol 117:75-79, 2006.
“CORE” CANINE VACCINES *
· Distemper
· Adenovirus (Hepatitis)**
· Parvovirus
· Rabies
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* vaccines that every dog and cat should have
** immunity provided by a CAV-2 vaccine
CANINE VACCINE ADVERSE EVENTS *
· retrospective cohort study; 1.25 million dogs vaccinated at 360 veterinary hospitals
· 38 adverse events per 10,000 dogs vaccinated
· inversely related to dog weight
· vaccines prescribed on a 1-dose-fits-all basis, rather than by body weight.
· increased for dogs up to 2 yr of age, then declined
· greater for neutered versus sexually intact dogs
· increased as number of vaccines given together increased
· increased after the 3 rd or 4th vaccination
· genetic predisposition to adverse events documented
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* from Moore et al, JAVMA 227:1102–1108, 2005
VACCINE CONCLUSIONS FOR CANINES *
Factors that increase risk of adverse events 3 days after vaccination:
· young adult age
· small-breed size
· neutering
· multiple vaccines given per visit
These risks should be communicated to clients
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* from Moore et al, JAVMA 227:1102–1108, 2005
