#1. This first article is a synopsis
of the latest AAHA position on vaccine guidelines, published in DVM NewsMagazine, see the February 2003 issue.
www.dvmnewsmagazine.com There is an AVMA update from Nov 2002 here. Below that is
the AVMA's "white paper" from 2001 on the same topic.
AAHA WRAPS UP CANINE VACCINE GUIDELINES
Three words summarize the recommended frequency of canine vaccinations-----triennially, annually or never.
That's the consensus of the American Animal Hospital Association's (AAHA) 14-member taskforce, which, at presstime, was working feverishly to compose a final draft of its first-ever canine vaccination guidelines. The final version, to be released this spring, is pending discussions with vaccine manufacturers. "The guidelines are huge," says Dr. Richard Ford, on the AAHA taskforce and professor of medicine at North Carolina State University. Dubbed a "paradigm shift" in vaccination protocol, the bottom line is: not all vaccines should be administered with equal frequency. "We have an abundance of referenced data that documents the longevity and the lack of efficacy of these various (canine) vaccines," says Ford.
Little more than three decades ago, veterinarians had limited vaccine choices: distemper, hepatitis, leptospirosis and rabies. Now more than two dozen different types of vaccines exist for dogs. Counting all the products, veterinarians have more than 100 vaccines at their disposal. "We're going through an explosion of vaccines for dogs, and to some extent similar for the cat," says Ford, who also contributed to the feline vaccination guidelines re-released by the American Association of Feline Practitioners in 2000. In response to the explosion, AAHA has proposed guidelines to offer direction on a vaccine protocol for veterinarians. "It's an attempt to provide recommendations, and I use the word 'recommendations'----these are not national standards," says Ford. "We are not dictating how veterinarians should actually vaccinate."
WHAT AAHA RECOMMENDS
For many vaccines the recommendation is still to vaccinate adult dogs annually. Other vaccines have proven safe and effective following a triennial administration. Puppies are a different story. Appropriate vaccine administration is
considered "absolutely the most important," says Ford. As a result, AAHA recommends veterinarians follow all prior vaccine protocols for puppies. For example, the committee universally stipulates that canine parvovirus vaccines should be given initially at six to eight weeks, the second dose at nine to eleven weeks and a third dose at 12-14 weeks. "The guidance provided by the vaccine manufacturers, the ones that have been in place for years and years are still being advocated (for puppies)," says Ford.
The previous rules don't apply when the puppy reaches adult stage, according to AAHA guidelines. "It's recommended, not required, that veterinarians place vaccines in one of two categories when developing a vaccine protocol for their practice: core or non-core," says Ford. The new categories are an attempt to segregate the vital vaccines from
the more discretionary, according to the taskforce. The core vaccines, of which there are four, are to be administered triennially. These are vaccines to prevent against high-risk, highly contagious and potentially fatal diseases. Noncore vaccines, to be administered under the discretion of the veterinarian, would follow an annual schedule. "We're trying to encourage veterinarians to look at the science behind the vaccines and to develop a vaccination protocol that is rational as well as effective," says Ford. Of the core vaccines, the taskforce recommends that the adult dog receive rabies; canine parvovirus vaccine; canine adenovirus-2 (hepatitis vaccine); and distemper vaccines every three years. The caveat to the recommendation, says Ford, is that there is good evidence that the protection conferred in adult dogs by both canine distemper and canine parvovirus exceeds five years. Three years seemed a conservative, happy medium for all parties involved, according to the taskforce.
The canine guidelines are "much less controversial" than the previously released feline vaccination guidelines, says Dr. Ron Schultz, veterinary immunologist at the University of Wisconsin - Madison and member of the taskforce. "It's hard to believe it'd be controversial to any DVM who's lived on earth for the past year or two. You'd have to be from outer space if you haven't heard about the issues,"says Schultz. "Yet individuals are still not aware of what the discussion is about," he adds. Ford likewise expects to hear minimal grumbling at the outset. "For some people this will be a surprise because....it's the classic culture change. We've always done it this way, my gosh, why are we going to change it now," he mimics. In response, he cites how today's vaccines have vastly improved immunogenic qualities and evidence points to long-term activity.
DIDN'T MAKE THE CUT
What may catch some veterinarians off guard is the taskforce's third classification, recommending against certain vaccines. Those are:
Giardia. Reason: no test is available for the disease; vaccine has not been proven to prevent infection, only reduces shedding.
Canine adenovirus-1. Studies found that the vaccine can cause visual impairment in dogs.
Coronavirus. "We're not recommending it because the disease isn't significant. The vaccine is safe, there just isn't a disease to go with it," Ford says. The recommendation may be controversial because coronavirus can be a viable revenue source for veterinarians since it is a more expensive vaccine, Ford adds. "We're saying don't give it. We don't feel that the disease justifies vaccinating dogs for it," says Ford. "Nobody's very happy with that (recommendation), and they'll argue it to the bitter end," says Ford.
AVMA WEIGHS IN
Aalthough the American Veterinary Medical Association says it has not seen a draft of the guidelines, Dr. Elizabeth Curry-Galvin, assistant director of scientific activities, says the two organizations shared concepts during the development of their respective reports. AVMA released its own position statement highlighting prudent use of vaccines late last year. In regard to AAHA's anticipated guidelines, AVMA's position is: "We encourage veterinarians to read the report once it is available. Practitioners need information from a wide number of sources to make the best medical recommendations for their patients," Curry-Galvin says.
CORE VACCINES (Triennial):
Rabies (May vary for adult dogs according to state law)
NONCORE VACCINES (ANNUAL, UNDER DISCRETION OF VETERINARIAN):
All the Leptospirosis vaccines (four types available)
#2. PRINCIPLES OF VACCINATIONS (Approved by the AVMA Executive Board April 2001; passed by the AVMA House of Delegates July, 2001, and printed in the JAVMA Sept 1, 2001 issue.)
Medical decisions about vaccine selection and protocols have become more complex. Selecting vaccine programs are among the most complicated of medical decisions facing the veterinarian. The reasons are numerous: continued evolution of the immune system; increased value of animals to the owner/client; improved medical record systems, and longer animal life-spans allowing the emergence of chronic sequellae. Improved understanding of infectious disease, the strengths and limitations of the biologic regulatory approval process, and of adverse events associated with vaccination, also complicate decisions required for best patient care.
The Council on Biologic and Therapeutic Agents (COBTA) has studied the issues of vaccinology and immunology for the last two years. This study included a review of the scientific literature and interactive testimony with four expert groups including academic, regulatory, industry, and practitioner experts. Topics included safety, efficacy, duration of immunity, research and development of vaccines, vaccine licensing, product labeling, adverse events and adverse event reporting, governmental oversight of manufacturers, and legal issues associated with medical procedures.
Vaccines have played a significant role in enabling people and animals to live longer and healthier lives in this world filled with microbial pathogens. Vaccine products vary in efficacy and safety. Modern science continues to learn more about the immune system and to develop strategies and technology for safer and more efficacious vaccines. Thorough evaluations of the risks of the disease, and those potentially associated with the vaccine, compared to the benefits of vaccination for the patient, are necessary in crafting optimal health recommendations that include vaccination.
COBTA concluded that there currently exists inadequate data to scientifically determine a single best protocol for vaccination or revaccination. Advances in antigen science, adjuvant function, impacts of different vaccine carrier solutions, and the immune system's actue and chronic reactions to stimulation, are impressive, but there remians gaps in our understanding. The body of knowledge about the variability of genetics within a breed or species, and the resulting impacts on an individual patient's response to vaccine or associated adverse reactions, is increasing but remains insufficient to make general recommendations. COBTA believes that variation in our patients and their lifestyle, and between the individual vaccine products available, requires a customized approach to best match the variation in the patients presented for immunization.
The practioner and client must make best patient care decisions where there exists a valid veterinarian-client-patient relationship. Vaccine decisions require a thorough and ongoing review of scientific information and expert opinion of this constantly evolving area to properly prepare the customized vaccine recommendations animal patients require.The one-year revaccination frequency recommendation found on many vaccine labels is based on historical precedent and United States Department of Agriculture regulation, not on scientific data. Even in those cases where scientific data was submitted to qualify the label claim, the data generated does not resolve the question about average or maximum duration of immunity.
There is evidence that some vaccines provide immunity beyond one year. Revaccination of patients with sufficient immunity does not add measurably to their disease resistance, and may increase their risk of adverse post-vaccination events. Vaccination is a potent medical procedure with both benefits and associated hazards. It is not currently possible to determine the immune status of a patient relative to all the infection diseases of concern without conducting a challenge test. Serology does not predicts a patient's immune status for most diseases. For those diseases where serology has predictive value of a patient's immune status, the variation within and between laboratories renders the procedure [of titering] generally unreliable.
Adverse events may be associated with the antigen, adjuvant, carrier, preservative, or a combination thereof. Possible adverse events include failure to immunize, anaphylaxis, immunosuppression, autoimmune disorders, transient infections, and/or long-term infected carrier states. In addition, a causal association in cats between injection sites and the subsequent development of a malignant tumor is the subject of ongoing research. The role of genetic predisposition to adverse events needs further exploration and definition.
Vaccine program goals include providing optimal immunity against clinically relevant diseases, including scientific data and opinion from experts, species and specialty groups, manufacturers, and governmnet agencies. All sources of scientific information and expert opinion need to be carefully and critically considered to properly prepare the suctomized vaccine programs animal patients require.
PRINCIPLES OF VACCINATION
1. Vaccination is a potent medical procedure associated with both benefits and risks for the patient. Adverse events, including some that are potentially severe, can be unintended consequences of vaccination.
2. The proper applicaion of vaccines to animal populations has enhanced their health and welfare, and prolonged their life-spans. The risks to animal health from non-vaccination are significant.
3. The goal for a vaccination program is to prevent disease and thereby promote optimal patient, herd, and/or public health.
4. Different patients require different vaccines and vaccination programs.
5. Unnecessary stimulation of the immune system does not result in enhanced disease resistance, and may increase the risk of adverse post-vaccination events.
6. Vaccination protects a population of animals by providing a level of resistance to a disease in those individual patients that are able to respond. Vaccination does not protect every individual patient even when they are properly vaccinated.
7. Disease carriers, including animals that shed the infectious agent but do not show signs of illness, are local sources of infection for susceptible animals. Sufficient immunity within a population of animals is an important component of preventing high rates of disease. Programs targeting immunization of unvaccinated animals are critical to disease control.
8. Knowledge of immunology and vaccinology, including associated benefits and risks, and the pathology of infectious diseases, are necessary to implement an effective vaccination program. Consideration of exposure, susceptibility, potential severity of disease, efficacy and safety of the vaccine, any potential public health concerns, and the owner's preferences are appropriate.
9. Only those veterinarians with valid veterinarian-client-patient relationships are in position to make recommmendations customized to the needs of the individual patient(s) and owner/client.
10. Revaccination recommendations should be designed to maintain clinically relevant immunity while minimizing adverse event potential.
11. Additonal imformation, including vaccine-specific scientific data on minimum, adverage, and maximum duration of immunity is desired to craft optimal revaccination frequency recommendations.
12. Vaccines, including polyvalent products, should be selected to include only those antigens appropriate for the specific risk needs of the patient, thereby eliminating unnecessary immune system stimulation and lowering potential risks of adverse effects.
13. Multiple dose vaccine vials must be carefully managed to: minimize the potential for delivering inappropriate levels of antigen of adjuvant; optimize the potential for maximum potency of the antigen present; and minimize the opportunity for contamination with extraneous microbes or chemicals.
14. Veterinarians should consider creating a core vaccine program, intended for use in the majority of animals in their practice area. Core vaccines are those that protect from diseases that are widely distributed in the region, virulent, and highly infectious, thereby posing a risk of severe disease. Core vaccines are efficacious and exhibit patient benefit:risk ratios high enough to warrant their use, and/or are of significant public health significance, or required by law.
15. Veterinarians should consider creating a non-core vaccine program, intended for a minority of animals in their practice area. Non-core vaccines are those that target diseases that are of limited risk in the region, and/or represent less severe threats to infected patients, and/or vaccine benefit:risk ratios are too low to warrant the use of these products in all circumstances, and/or scientific infrmation is inadequate to evaluate these products. Veterinarians and owners/clients need to carefully consider the benefits and risks of using these vaccine products on an individual basis.
16. Information about the benefits and risks of vaccination are important to owners' decisions about individual vaccine selection and vaccination program choices.
17. USDA licensed products have had the manufacturer's claims about vaccine performance substantiated by a variety of testing methods. Careful evaluation of labels and other information is necessary to compare and contrast between the available products.
18. There is a critical need for more fully developed, scientifically based, and statistically valid evaluation of vaccine products to provide practitioners with a basis for developing vaccination programs that maximize benefits and minimize associated risks for the patients under their care.
19. Current adverse event reporting systems need significant improvement in the capture, analysis, and reporting of adverse events. Practitioner conmmitment to adverse event reporting, and timely access for practitioners to curent analysis of adverse event data, are essential to porviding optimal patient care.
20. There is a potential legal liability for all medical procedures including vaccination.
Biological agents are regulated by the USDA, not the Food and Drug Administration, and thus are not subject to those regulations that address extra label use. Veterinarians can legally use vaccines in a discretionary manner. USDA licensing at the full approval level provides a baseline standard for efficacy, safety, purity, and potency, but the clinical need (relevancy) or usefulness (applicability) of a product are not assured by the licensing process. The USDA must approve labels for biological products. However, current lagels requently contain revaccination interval recommendations based on historical precedence and regulation rather than scientific data, may fail to adequately inform practitioners about otimal use of the product, and the testing methods may be inadequate to identify rare but relevant safety concerns.
Labels on licensed vaccines make different claims and should be carefully studied when evaluating products. Claims may, for example, declare the product (a) prevents infection, (b) prevents disease, or (c) results in a decreased number or a decreased intensity of clinical signs. Each of these claims represents a different level of performance outcome that might be important in selection of a specific vaccine. USDA approved products licensed under the conditional approval process have demonstrated a reasonable expectation of efficacy. Autogenous vaccines have no demonstrated efficacy.