Hello everyone,

Dr. Ron Schultz, PhD, University of Wisconsin, Madison

The following points are taken from the abstract of Dr. Ron Schultz’s presentation on vaccinations.  I’ve listed these points to help you decide how much of this long, detailed presentation you will take time to read.  There are 19 pages.  Actually, I thought that these points were kind of like “teasers.”  They are points I think are extremely important, but I’m sure I didn’t include others that you would think are important.  I’m going to discuss with Debbie how to file the entire presentation so it is available for future review.  Remember as you read the following, that we can’t format or use bold on this list so things can run together.  For purposes of understanding what I included, use the space between the paragraphs to know that these topics are taken out of the context of the entire presentation.

I also included the 37 most frequently asked questions about vaccinations.  I included one very interesting chart about minimum duration of immunity of vaccines, but don’t know if it will format in a readable form.  If not, you will be able to see it in the files section or ask me to send you the “entire” 19 pages.

From the presentation:

 A “more is better” philosophy often prevails with regard to pet vaccines.  On many occasions practitioners say that “I know many of the vaccines I administer probably aren’t needed but it won’t hurt to give them and who knows the animal may need them some time during their life because of unknown risk.”  I have also been told by many practitioners that “I believe the duration of immunity for some vaccines like distemper, parvovirus and hepatitis is many years, but until I find another way to get the client into my office on a regular basis I'm going to keep recommending vaccines annually.” 

1) the annual revaccination recommendation on the vaccine label is evidence the product provides immunity for (only) one year. – Not True.  It may not even provide a year’s immunity – or it may provide a lifetime of immunity.

 
In fact most of the companies have now demonstrated their core products provide at least 3 years of immunity and some give a written guarantee.

 
5) if they don’t continue to revaccinate annually, diseases like canine distemper, canine parvovirus and infectious canine hepatitis (CAV-1) will “reappear and cause widespread disease similar to what was seen prior to the development of vaccines for these diseases.” – Not True.  The diseases will only reappear if there is no vaccination in a large percentage of the population with core vaccines.

9) “It’s much cheaper to revaccinate the pet annually than it is to treat the disease the animal will develop because it didn’t get revaccinated annually.”  The “better safe than sorry” philosophy -  It is less expensive to prevent disease.  However, if the core vaccines are given as a puppy and again at a year of age, then annual revaccination is not needed!  Furthermore, if a vaccine is given that is not needed and it causes an adverse reaction that is unacceptable and can be very expensive

11) ”Dogs need to be revaccinated annually up to 5 to 7 years of age, then and only then would vaccination every three years be okay.” – Not True

I believe every practitioner, kennel owner and dog owner should know the following general information about canine vaccines and vaccination programs.  What vaccines are needed for all puppies?  I do mean all pups, as we only vaccinate approximately 50% of dogs.  If we could increase this percentage to 75%, we would be able to eliminate many of the diseases prevented by core vaccines.  The “core vaccines,” those that every pup should receive and identified as core by most canine vaccine experts and the AAHA Canine Task Force in the United States, include: 1) Canine Parvovirus type 2 (CPV-2), 2) Canine Distemper virus (CDV), 3) Canine Adenovirus type 2 (CAV-2), 4) Rabies Virus (RV).  When do the core vaccines need to be given?  As a minimum, puppies should be given at least one dose at 16 weeks of age or older.  Preferably, they should be given three or more times starting at 6 to 9 weeks (I prefer 8 or 9), then at intervals of 2 to 4 weeks.  For example, vaccinate at 9, 12, and 15 weeks.  It is critical that the last dose be given at 14 to 16 or more weeks of age, regardless of number of doses given earlier.  It is also important not to give vaccines earlier than 5 to 6 weeks unless there is a significant risk of a specific disease, then give only the vaccine for the disease you want to prevent (e.g. CPV-2).  Never vaccinate a pup less than 4 weeks of age, because the modified live vaccines are not designed for these very young animals.  The most effective canine core products currently will include modified live and recombinant vaccines alone or in combination.  The combination products with CPV-2, CDV and CAV-2 currently often include canine parainfluenza (CPI) virus.  New “core only” products have been and are being developed that don’t have CPI, however, the CPI will not cause a problem if and when used as a parenteral 5 way combination product.  However, the most effective route to vaccinate for CPI is intranasal, as local immunity is more important than systemic immunity.

After the puppy vaccination series is completed, revaccination is recommended by AAHA Canine Guidelines again at one year of age or one year after the last puppy vaccination.  Rabies must be given again at 1 year, then every 3 years, whereas, the other core vaccines need not be given again after the one year dose for at least 3 or more years.  There is no benefit from annual rabies vaccination and most one year rabies products are similar or identical to the 3-year products with regard to duration of immunity and effectiveness.  However, if they are 1 year rabies vaccines, they must be legally given annually!  Rabies vaccine is the only canine vaccine requiring a minimum duration of immunity study by the USDA.  However, revaccination annually does not necessarily improve immunity.  However, annual revaccination does significantly increase the risk for an adverse reaction in the dog.  I would recommend, if you really want to be sure the puppy vaccination program was successful, that a CDV and CPV-2 antibody test be performed 2 or more weeks after the last puppy vaccination.  Laboratory tests as well as “in-office test” for CDV and CPV-2 are available.  If there is no antibody, revaccinate and perform a test two or more weeks after revaccination.  If you still don’t have antibody, change the product and revaccinate.  Antibody tests (titers) are very useful at these times to ensure the animal is immunized.  The problem with antibody tests is they are often very expensive, thus in general, these tests won’t be used.  As an alternative to routinely revaccinating at one year for CDV, CPV-2 and CAV-2, I would revaccinate at 6 months to help ensure the animal has responded to the last dose in the puppy series rather than waiting until 1 year, as we recommend in the AAHA Guidelines.  Then, revaccinate not more often than every 3 years.  The minimum duration of immunity for the core vaccines except rabies is at least 7 years based on challenge and/or titers (Table 1).  Thus revaccinating annually will not improve protection.  Ironically “the better safe than sorry philosophy” can be equally applied to less vaccination, since the animal that develops an adverse reaction (e.g. hives, facial edema, anaphylaxis) from a revaccination that wasn’t needed is an example of “being sorry, not safe!”

 At present most canine core vaccines are given more often than needed, but a few non-core vaccines probably not often enough to be of benefit.  Also, many vaccines are given that are not needed or that cannot be shown to provide a benefit for the specific animal.  Vaccines are medical products that should only be given if needed and only as often as is necessary to provide protection from diseases that are a risk to the health of the animal.  If a vaccine that is not necessary causes an adverse reaction that would be considered an unacceptable medical procedure, thus use only those vaccines that are needed and use them only as often as needed. 

 
Vaccination programs are changing and they will continue to change.  The vaccination program must be tailored to the individual animal.  Vaccines are medical products that should not be used as practice management tools.   My general philosophy is to vaccinate more animals in the population, but vaccinate them only with those vaccines that the animal needs and only as often as required to maintain protective immunity. 

Be wise and immunize, but immunize wisely!

Why Vaccination Programs are Changing

Why, when you know from personal experience that life-long immunity exists for many human vaccines, do you have great difficulty believing a canine vaccine can provide life-long immunity?  Perhaps I and my colleagues that teach immunology to veterinary medical students have failed to explain the basics of vaccine induced “immunologic memory.”  Immunologic memory is as the term implies the immune system’s ability to remember the vaccine antigens that it has seen at an earlier time in life, allowing the immune system to respond in a manner that will protect you or your dog from specific infections and/or diseases.

The three most important viral infections/diseases of dogs all provide life-long immunity.  They are CDV, CPV-2, and CAV-1 (the vaccine to CAV-2).  If a puppy is immunized with the three MLV vaccines (or the recombinant canarypox vectored CDV) used to prevent these diseases, there is every reason to believe the vaccinated animal will have up to life-long immunity!  The vaccines that prevent the diseases caused by these 3 viruses plus rabies vaccine are the “Canine Core Vaccines” or those vaccines that every puppy should receive. 

I and my colleague, Dr. Fred Scott, first proposed a three year revaccination program for dogs and cats more than 25 years ago, when we published an article in Veterinary Clinics of North America 8(4) 755-768, 1978.  Today, a three year revaccination program has been recommended in the AAHA Canine Vaccination Guidelines and the American Association of Feline Practitioners Vaccine Guidelines for Cats. 

You and your client will need to determine what vaccines and vaccination program are best for the animal and your client.  The program selected may only include core vaccines that are given once in the lifetime of the dog or the program may include all vaccines with revaccination on an annual or more often basis, or it may be a vaccination program in between these two extremes depending on what your patient and client’s needs are and what, in your medical judgment as the veterinarian, is best for your patients.  Your decision should depend on the life style of the animal, its medical history, health status, age, pregnancy status and other important factors and not on using the vaccine as a practice management tool to get the clients to bring their animals in on an annual or semi-annual basis for a wellness visit.

Frequently Asked Questions (FAQ)

© 2007 M. Horzinek, M.J. Day, R.D. Schultz

1. Is there a risk of over-vaccinating a pet (e.g. injecting it too often, or using vaccines that are not required for the specific pet)?

Yes – Vaccines should not be given needlessly, as they may cause adverse reactions. Vaccines are medical products that should be tailored to the needs of the individual animal.

2. May I mix different types of vaccines in the syringe?

No - One should never mix different vaccine preparations in the syringe unless specified by the data sheet.

3. May I co-inject different vaccines (not part of a single commercial product) into the same animal?

Yes – but different vaccines should be injected into separate sites that are drained by different lymph nodes.

4. May I use smaller vaccine doses in small breeds to reduce the risk of adverse reactions?

No - The volume (e.g. 1.0 ml) as recommended by the manufacturer generally represents the minimum immunizing dose, therefore the total amount must be given.

5. Should the large dog (Great Dane) be injected with the same volume of vaccine as the small dog (Chihuahua)?

Yes - Unlike pharmaceuticals that are dose-dependent, vaccines are not based on volume per body mass (size), but rather on the minimum immunizing dose.

6. May I vaccinate the anaesthetized patient?

It is best not to do this if possible - the patient may develop a hypersensitivity reaction and vomit, leading to an increased risk of aspiration. Also, anaesthetic agents may be immunomodulatory.

7. May I vaccinate pregnant pets?

No - Vaccination with MLV and killed products during pregnancy should be avoided, if at all possible.

8. May I vaccinate pets that are on immunosuppressive or cytotoxic therapy (e.g. for cancer or immune-mediated diseases, such as those with an autoimmune or hypersensitivity pathogenesis)?

No - Vaccination especially with MLV products should be avoided as they may cause disease; vaccination with killed products may not be effective or may aggravate the immune-mediated disease.

9. How long after stopping immunosuppressive therapy do I wait before vaccinating a pet?

A minimum of 2 weeks.

10. May I vaccinate every week if an animal is at high risk of disease?

No - Vaccines should not be given more often than every other week, even when different vaccines are being given.

11. When should the last vaccine dose be given in the puppy and kitten vaccine series?

The last dose of vaccine should be given at around 16 weeks of age.

12. May I inject a killed vaccine, followed at a later time with a MLV for the same disease?

No - The killed vaccine may induce an effective antibody response that will neutralize the MLV in the vaccine, thereby preventing immunization. It would be preferable to give the MLV vaccine first and if/when needed, revaccinate with the killed vaccine preparation.

13. May I inject a modified live intranasal Bordetella vaccine?

No - The vaccine can cause a severe local reaction and may even kill the pet.

14. May I give a killed Bordetella vaccine destined for parenteral use intranasally?

No - This will not stimulate a specific response to the Bordetella; you should give a live vaccine via the intranasal route, as specified by the data sheet.

15. Are precautions necessary when using MLV FHV-1/FCV parenteral vaccines in cats?

Yes - Mucosal (e.g. conjunctival and nasal) contact with the preparation must be avoided, because the vaccine virus can cause disease.

16. Can nosodes (holistic preparations) be used to immunize pets?

No - Nosodes cannot be used for the prevention of any disease. They do not immunize because they do not contain antigen.

17. Should dogs and cats with a history of adverse reaction or immune-mediated diseases (hives, facial oedema, anaphylaxis, injection site sarcoma, autoimmune disease, etc.) be vaccinated?

If the vaccine suggested to cause the adverse reaction is a core vaccine, a serological test can be performed, and if the animal is found seropositive (antibody to CDV, CPV-2, FPV) revaccination is not necessary. If the vaccine is an optional non-core vaccine (e.g. Leptospira bacterin) revaccination is discouraged. For rabies, the local authorities must be consulted to determine whether the rabies vaccine is to be administered by law or whether antibody titre may be determined as an alternative.

18. May I use different vaccine brands (manufacturers) during the vaccination program?

Yes – It may even be desirable to use vaccines from different manufacturers during the life of an animal, because different products may contain different serotypes (e.g. of feline calicivirus).

19. Should I use a disinfectant (e.g. alcohol) on the injection site?

No - The disinfectant might inactivate an MLV product, and it is not known to provide a benefit.

20. Can vaccines cause autoimmune diseases?

Vaccines themselves do not cause autoimmune disease, but in genetically predisposed animals they may trigger autoimmune responses followed by disease – as can any infection, drug, or a variety of other factors.

21. May I split vaccines in combination products?

Yes - For example, Leptospira bacterins are often the diluent for the viral antigen combination. The “viral cake” may be resuspended in sterile water, and the Leptospira bacterin be given separately at another site or time, or discarded.

22. Will a single vaccine dose provide any benefit to the dog or cat?

Will it benefit the canine and feline populations?

Yes - One dose of a MLV canine core vaccine (CDV, CPV-2 CAV-2) or a feline core vaccine (FPV, FCV, FHV-1) should provide long term immunity when given to animals at or after 16 weeks of age. Every puppy and kitten 16 weeks of age or older must receive at least one dose of the MLV core vaccines.

If that were done, herd (population) immunity would be significantly improved. Even in the USA with its good vaccination record, probably <50% of all puppies and <25% of all kittens ever receive a vaccine. We must vaccinate more animals in the population with core vaccines to achieve herd immunity (e.g. 75% or higher) and prevent epidemic outbreaks.

23. When an animal first receives a vaccine that requires two doses to immunize (e.g. killed vaccines like Leptospira bacterins or feline leukemia virus), and it does not return for the second dose within ≤6 weeks, is there any immunity?

No - A single dose of a two-dose vaccine does not provide immunity. The first dose is for priming the immune system, the second for boosting. If a second dose is not given within 6 weeks of the first, the regime must start again, making sure the two doses are given within 2 to 6 weeks. After those two doses, revaccination with a single dose can be done at any time.

24. May I give a MLV product to a wild, exotic species or to a domestic species other than to the ones which the vaccine was licensed to protect?

No - Never. Many MLV vaccines have caused disease in animal species other than those for which they had been licensed. Even worse: the vaccine could be shed from those animals, regain virulence through multiple passages and cause disease even in the target species for which it had been developed. The consequences could be catastrophic!

A highly effective and very safe vaccine for species that are susceptible to CDV is a canary poxvirus-vectored recombinant CDV vaccine that is available as a monovalent product for ferrets or a combination product for dogs. The monovalent vaccine is being used in many wild and exotic species susceptible to CDV.

25. May I vaccinate a puppy that is at high risk of getting CDV with a human measles vaccine?

No - Due to an insufficient amount of virus, the human MV vaccine is not immunogenic in the puppy. Measles virus vaccines made specifically for the dog (sometimes combined with CDV) will give temporary protection at an earlier age than a CDV vaccine. At 16 weeks or older, the puppy must be vaccinated with a CDV vaccine, to achieve permanent immunity.

26. I know that maternally derived antibodies (MDA) can prevent active immunization with MLV vaccines - but can they also block immunity to killed vaccines?

Yes - MDA can indeed block certain killed vaccines. If the killed product requires two doses, as is often the case, and the first dose is blocked by MDA, then the second dose will not immunize. In this circumstance, the second dose will prime (if not blocked), and a third dose is required to boost and immunize.

This is not true for MLV, where - in the absence of MDA - it only takes a single dose to prime, immunize, and boost. Nevertheless two doses are often recommended, particularly in young animals, to be sure one is given when MDA cannot block. That is why in the puppy or kitten series, the last dose should be given at around 16 weeks of age or later.

27. I have been told that certain canine MLV combination core products need only be given twice, with the last dose at an age as young as 10 weeks. Is that accurate?

No - it is not. No combination core product currently available will immunize an acceptable percentage of puppies when the last dose is given at 10 weeks of age. The last dose should be given at around 16 weeks of age, regardless of the number of doses given earlier.

In the presence of MDA, MLV vaccines either immunize or they don’t, and the animal will be either immune or not immune - there is nothing in between. MLV vaccines do not give a little immunity with any dose when blocked by MDA.

28. For how long can a reconstituted MLV vaccine sit at room temperature without losing activity?

At room temperature, some of the more sensitive vaccines (e.g. CDV, FHV-1) will lose their ability to immunize in 2 to 3 hours, whereas other components will remain immunogenic for several days (e.g. CPV, FPV).

29. May I give the same type of vaccine parenterally and intranasally, for example the canine and feline vaccines used to prevent respiratory diseases (‘kennel cough’ and feline upper respiratory disease)?

Yes - But be sure to give the product approved for that route. If you use the parenteral MLV vaccines containing FCV and FHV-1 locally, you could cause disease in the cat. If you use the killed FCV and FHV-1 vaccines locally, you would not get any immunity and might cause significant adverse reactions. If you gave the intranasal live ‘kennel cough’ vaccine parenterally, you could cause a severe necrotizing local reaction and even kill the dog, whereas giving the parenteral killed Bordetella vaccine intranasally will not immunize and may cause a hypersensitivity reaction.

However, both types of products can be given at the same time or at various times in the life of the animal. Vaccinating both parenterally and intranasally may actually provide better immunity than vaccinating at only one site. Thus parenteral vaccination provides protection in the lung but little or no immunity in the upper respiratory tract (especially local secretory IgA and CMI), whereas intranasal vaccination will engender good secretory IgA and local CMI and non-specific immunity (e.g. type I interferons), but will not always provide immunity in the lung.

30. Are there dogs and cats that cannot develop an immune response to vaccines?

Yes - This is a genetic characteristic seen particularly in some breeds, and these animals are called ‘non-responders’. Genetically related (same family or same breed) animals will often share this non-responsiveness. If the animal is a non-responder to a highly pathogenic agent, like canine parvovirus or feline panleukopenia virus, the infected animal will die if infected. If it is a non-responder to a pathogen that rarely causes death, it may become very sick but will survive (e.g. after a Bordetella bronchiseptica infection).

31. Are there mutants (biotypes or genotypes) of CDV or CPV-2 in the field that the current vaccines cannot provide protective immunity against?

No. - All the current CDV and CPV-2 vaccines provide protection from all the known isolates of CDV or CPV-2, respectively, when tested experimentally as well as in the field.

32. How long after vaccination does it take for the dog to develop immunity that will prevent severe disease when the core vaccines are used?

This is dependent on the animal, the vaccine, and the disease.

·        The fastest immunity is provided by CDV vaccines – MLV and recombinant canarypox virus vectored. The immune response starts within minutes to hours and provides protection within a day to animals without interfering levels of MDA and dogs that are not severely immunosuppressed.

·        Immunity to CPV-2 and FPV develops after as few as 3 days and is usually present by 5 days when an effective MLV vaccine is used. In contrast, the killed CPV-2 and FPV-2 vaccines often take 2 to 3 weeks or longer to provide protective immunity.

·        CAV-2 MLV given parenterally would provide immunity against CAV-1 in 5 to 7 days; when given intranasally, however, the same level of immunity to CAV-1 is not present until after 2 or more weeks.

·        Time from vaccination to immunity is difficult to determine for FCV and FHV-1 because some animals will not develop any immunity.

 33. Will the current ‘kennel cough’ vaccines provide any protection from disease caused by the new canine influenza virus?

 No - The racing greyhounds that have been found infected and that developed disease had been routinely vaccinated 3 or more times a year with commercial ‘kennel cough’ vaccines. Canine influenza virus is antigenically unrelated to any other virus of dogs, but related to Equine Influenza Virus.

34. If an animal has gone beyond the time that is generally considered to be the maximum DOI for the vaccine (7 to 9 years for CDV, CPV-2, CAV-2; >1 year for Leptospira, Bordetella bronchiseptica; >3 years for rabies), do I have to start the series of vaccinations again (multiple doses 2 to 4 weeks apart)?

No - For MLV vaccines, multiple doses are only required at the puppy or kitten age, when an animal has MDA.

35. What can I expect from the core vaccines in terms of efficacy in the properly vaccinated puppy/dog and kitten/cat?

·        Dogs properly vaccinated with MLV or recombinant CDV, CPV-2 and CAV-2 would have ≥98% protection from disease. Similarly we would expect a very high protection from infection.

·        For the properly vaccinated cat that had received MLV vaccines, we would estimate that ≥98% would be protected from disease and infection with FPV.

·        In contrast, we can expect FCV and FHV-1 vaccines, at best, to protect from disease, especially in a highly contaminated environment (e.g. shelter) and protection would be seen in 60 to 70% in a high risk environment and higher in the household pet cat.

36. Are serum antibody titres useful in determining vaccine immunity?

Yes - Especially for CDV, CPV-2 and CAV-1 in the dog, FPV in the cat and rabies virus in the cat and dog. Serum antibody titres are of limited or no value for the other vaccines. Assays for CMI are of little or no value for any of the vaccines for various technical and biological reasons. Such factors are less of an issue for serological tests where it is much easier to control many of the variables. However, discrepant results are still obtained, depending on the quality assurance program of the given laboratory.

37. Do puppies develop immunosuppression after the initial series of core vaccines?

Yes - If a combination product containing MLV-CDV and MLV-CAV-2 with other components is used, a period of immunosuppression lasting approximately 1 week develops, beginning 3 days after vaccination. If the combination vaccine does not contain either MLV-CDV or MLV-CAV-2, then such suppression does not occur.