Advances in Canine Infectious Diseases, Carmichael L. (Ed.)
International Veterinary Information Service, Ithaca NY (www.ivis.org),
Considerations in Designing Effective and Safe Vaccination Programs
for Dogs (Last Updated: 5-May-2000 )
During the past 50 years many vaccines have been developed to prevent a
variety of infectious diseases of dogs. Currently there are 16 canine
vaccines licensed in the USA which are available commercially (Table 1).
Although a few of the vaccines are available as monovalent products
(e.g. rabies, canine
parvovirus), most are available only as multi-component products
that contain between 2 to 10 components. Some vaccines have had a
profound effect by reducing, or eliminating, diseases characterized by
moderate to high morbidity and/or mortality. However, other vaccines
have had little or no recognized beneficial effect because they were
designed to prevent infections that cause little or no morbidity and/or
mortality. Some vaccines are so new that the potential benefits they
provide are not known e.g., Giardia, Leptospira (L.)
grippotyphosa and L. pomona.
|Table 1. List of the
Licensed Canine Vaccines Available Commercially in the United
Distemper Virus (MLV)
Canine Distemper Virus/Measles Virus (MLV)
Canine Parvovirus-2 (MLV, K)
Canine Adenovirus-1 (K)
Canine Adenovirus-2 (MLV, K)
Parainfluenza Virus (MLV)
Coronavirus (MLV, K)
Rabies Virus (K)
Bordetella bronchiseptica (MLV, K)
Borrelia burgdorferi (Lyme) (K, KR)
Leptospira canicola (K)
Leptospira grippotyphosa (K)
Leptospira icterohaemorrhagiae (K)
Leptospira pomona (K)
MLV = Modified Live Vaccine; KR = Killed Recombinant Vaccine; K =
Killed Vaccine; LRV = Live Recombinant Vaccine
1 Only a few of these vaccines are available as monovalent
products. Almost all commercial products contain two or more of these
vaccines. The most common multi-component product contain CDV, CPV-2,
CAV-2, CPI, Leptospira canicola, Leptospira
icterohaemorrhagiae. This product is often referred to as a
"7-way vaccine" because it should protect against (CAV-2 and
CAV-1) in addition to the other 5 components.
Canine vaccines which are considered essential, and should be given to
every dog, are termed "core vaccines". All other vaccines are
regarded as "non-core" and should be used in dogs considered
at high risk on an as needed basis. Core vaccines are considered
essential because they are designed to prevent important diseases that
pose serious health threats to susceptible dogs, irrespective of
geographic location or the life style of a dog. Some
"non-core" vaccines also may be considered "core"
because they are designed to prevent a disease that is a potential
public health threat.
Efficacy and safety of a product are critical in deciding whether a
vaccine should be considered core. Diseases that pose a serious risk to
susceptible dogs, or to public health, which are readily preventable by
current vaccines include rabies, a major public health disease caused by
the rabies virus (RV); canine parvovirosis caused by canine parvovirus-2
(CPV-2); canine distemper caused by canine distemper virus (CDV), and
infectious canine hepatitis (ICH) caused by canine adenovirus type-1
(CAV-1). ICH is effectively controlled by canine adenovirus-2 (CAV-2)
vaccine which has replaced CAV-1 vaccines because it is much safer. As
part of a minimum disease prevention program, every dog should receive
CPV-2, CDV, CAV-2 and rabies vaccines at least one time at or after the
age of 12 weeks (Table 2). If that were the only vaccination a dog ever
received, and the products used were modified live CPV-2, CDV, CAV-2 and
a 3-year killed rabies, the dog would have a >80% probability of
developing immunity to those four viruses for 3 or more years.
Vaccination programs for highly contagious diseases are most effective
when all, or the highest percentage possible, of animals in the
population have been vaccinated. Therefore, every effort should be made
to ensure that as many dogs as possible over the age of 12 weeks are
vaccinated with at least one dose of the four core vaccines.
|Table 2. Duration of
Immunity and Efficacy for Canine Vaccines Commercially
Available in the United States.
||Minimum Duration of Immunity
||Estimate of Relative Efficacy (%)
|Borrelia burgdorferi (Lyme
1 Experimental challenge studies and/or serologic studies
have been performed. Field experience during outbreaks also confirm
experimental challenge studies.
2 Based on field experience and observations from outbreak
studies and clinical records. Reliable experimental or controlled
studies often not available.
3 Not available; cannot be determined. CCV has not been shown
to cause significant disease.
4 Vaccines recently licenced; information not available
except from company data.
5 See text.
Minimum Disease Prevention
In the United States, which has the highest percentage of vaccinated
dogs, I estimate that less than 60% of all dogs receive the minimum
disease prevention vaccination program (Table 3). In many countries less
than 30% of dogs receive this one time vaccination with the four core
vaccines. Efforts to increase the percentage of vaccinated dogs will
require a better understanding by veterinarians and dog owners of the
importance, effectiveness and safety of this one time vaccination
program. In contrast to a minimum disease prevention program, the
vaccination programs for the majority of well cared for pets are
vaccination practices considered to provide "maximum disease
prevention". Thus, most pet dogs receiving routine veterinary care
are given the core vaccines several times; in addition, they routinely
receive several of the non-core vaccines. Based on a national survey
that we have done during the past 2 years, a majority of veterinary
practices began the puppy vaccination program at, or shortly after, 6
weeks of age. The product used most often was a multi-component vaccine
containing CPV-2, CDV, CAV, canine parainfluenza (CPI) virus, and L.
canicola plus L. icterohemorrhagiae bacterins. Approximately
50% of dogs received Canine
Coronavirus (CCV) in combination or as a separate vaccine. The pups
were then revaccinated 3 to 5 times with the same product at 2 to 4 week
intervals until they reach an age of 14 to 18 weeks. One dose of rabies
vaccine was given at 12 to 16 weeks of age. In approximately 25% of
animals, two or more doses of an intranasal vaccine containing Bordetella
bronchiseptica (B. bronchiseptica) and CPI-virus was given to
pups before 18 weeks of age! Additionally, Lyme
vaccine (Borrelia burgdorferi) is sometimes included in the
puppy program. In the majority of practices, dogs would then be
revaccinated with the vaccines noted above at least annually for the
remainder of their lives. An exception to annual revaccination is
rabies, which would be given at 1 year of age, and then once every 3
years thereafter, unless more frequent vaccination was required by law
or believed necessary by the veterinarian.
Table 3. Vaccination Programs for Dogs.
|"Core" Vaccines (Every Dog)
|Program A - Minimal Approach
Primary Immunization at 12 weeks or older
- Canine parvovirus-2 (CPV-2)
Distemper Virus (CDV)
- Canine Adenovirus (CAV-2)
and Rabies Virus
Note: Canine Parainfluenza (CPI)
will have to be included since there are no products with
CPV-2, CDV and CAV-2 without CPI.
Rabies - 1 year after primary, then once every 3 years.
Other vaccines would not be given again.
|Program B - Moderate Approach Primary
- 6 to 9 weeks - CPV-2 + CDV
- 12 to 15 weeks - Rabies, CPV-2 + CDV + CAV-2 + CPI*
- 1 Yr. later - Rabies, CPV-2 + CDV + CAV-2 + CPI*, then
again every 3 years for rabies; every 3 -5 years for other
*See note under Program A
|Program C - Maximal Approach
- 6 to 8 weeks - CPV-2 +CDV - 9 to 11 weeks - CPV-2
+ CDV + CAV-2 + CPI* - 12 to 14 weeks - Rabies, CPV-2 +
CDV + CAV-2 +CPI*
- 1 Yr CPV-2 + CDV + CAV-2 + CPI* + Rabies. - 3 Yr
CPV-2 + CDV + CAV-2 + CPI* + Rabies. *See note under Program A
|"Non-Core" Vaccines (Give
only if the dog is at high risk and then only the vaccine that
|Program D - Minimal Approach
- Give only "core" vaccines
("Non-core" vaccines are not given)
|Program E - Moderate Approach
- 6 weeks of age, or older - 1 dose of intranasal B.
bronchiseptica + CPI*
- 12 week and 14 to 15 weeks - 2 doses of Leptospira
bacterin (2- or 4-serovars)
- Annually - Leptospira bacterin + intranasal B.
bronchiseptica + CPI*
*See note under Program A
|Program F - Maximal Approach
Primary Immunization - 6 to 14 weeks of age - 2
doses Intranasal B. bronchiseptica + CPI*
- 9 to 11 weeks and 12 to 14 weeks - Leptospira
bacterin (2-serovars or 4-serovars)
- 9 to 11 and 12 to 14 weeks - 2 doses Lyme
- 6 to 8 weeks and 9 to 11 weeks - 2 doses Giardia
*See note under Program A
- Annually with intranasal B. bronchiseptica and
- At least annually with Leptospira bacterin
(2-serovars or 4-serovars)
- Lyme vaccine - annually, a few months prior to peak
- Omit Giardia vaccine
|When Canine Parvovirus is a serious threat:
monovalent MLV product starting at 5 weeks of age then giving
the product every other week until 15 weeks of age. A more
reliable program would be to determine antibody titers to
CPV-2 and vaccinate pups when CPV-2 antibodies no longer
interfere with immunization.
When Canine Distemper is a serious threat:
virus - CDV combination at 4 to 6 weeks of age; then a
product containing CDV without MV at 12 weeks of age or older.
Program A, B, or C for "core" products can be
matched with any of the "non-core" product
programs D, E, or F. Therefore, Program A can be matched with
D (no "non-core" product given) or with F, where any
of the non-core vaccines needed could be given and given again
annually for dogs at high risk. Vaccination more often than
listed in C and F should rarely, if ever, be done.
Considering the difference between the minimum disease prevention
program that protects >80% of dogs from the important canine diseases
and the program described above, it is not surprising that neither the
dog-owning public nor veterinarians appreciate the exceptional benefit
derived from the "minimum disease prevention program".
Why are there significant differences in number of doses and components
of vaccines routinely given in the maximum vs. minimum disease
prevention programs? Those differences arise primarily from
misperceptions about how vaccines work, which vaccines are necessary,
and how often vaccines should be given during the life of the dog to
provide protective immunity.
Common Questions Regarding Vaccines/Vaccination
- At what age should the vaccination program begin?
- How often does a dog need to be revaccinated? (What is the
duration of immunity?)
- How does one determine the risk of disease, and therefore the
necessity for one or more of the "non-core" vaccines?
- How effective are the vaccines?
- Do all current vaccines for a given disease provide similar
- What are the risks of causing adverse reactions with certain
vaccines or when giving vaccines too often?
Those questions are being asked more now than in the past since most
vaccine experts, and many dog owners, believe that certain vaccines are
given too often and some are unnecessary. Answers to the above questions
are complex and depend on the needs of a particular animal as well as
the expectations of the owner and veterinarian. [1-5].
At What Age and Which Vaccines to Use?
Unfortunately, simple and universally agreed on answers are not
available. Most experts agree that puppy vaccination programs should
begin at 6 to 9 weeks of age; the first puppy vaccination should begin
prior to 6 weeks of age only in special situations, e.g., humane
shelters. Vaccination at less than 6 weeks of age is often not effective
due to interference of vaccinal immunity by passively acquired
antibodies and, rarely (e.g. <2 weeks of age), inability of a pup's
immune system to respond effectively to the vaccine. Ideally, pups
should be kept in a clean environment prior to vaccination and have no,
or minimal, contact with dogs other than the dam and littermates. The
first and second doses of vaccine in a puppy series optimally includes
only the CPV-2 and CDV components. Those are the most important vaccines
for a pup less than 12 weeks of age because canine parvovirus and canine
distemper are the two most serious infectious diseases of dogs.
CPV-2 is now the most important vaccine in the USA since pups are most
likely to encounter this virus because of its high prevalence and
environmental stability. When CDV is a major threat to young pups, as in
known distemper-infected kennels or humane shelters, the most effective
product is the combined measles virus (MV)-CDV vaccine. This product can
be used in pups as young as 4 weeks of age when necessary. When MV-CDV
is used, revaccination should be done with a CDV product that does not
contain MV. After 9 weeks of age, the vaccine regimen should include a
rabies vaccine (12 weeks or older) and multi-component vaccines (CPV-2,
CDV and CAV). All current commercial products also contain CPI virus,
however, CPI is not needed in the parenteral vaccine since it is often
given and is more effective when given intranasally in combination with
B. bronchiseptica. Intranasal products are available which contain CAV-2
in addition to B. bronchiseptica and CPI. Use of the three-way
intranasal product would eliminate the need to give CPI and CAV-2
Leptospira bacterins, if needed, should ideally be given at 9
weeks of age or older. Leptospira bacterins require two doses of
vaccine which should be given at intervals of 2 to 4 weeks between
doses. Multiple doses of modified live viral vaccines are generally
required only in pups less than 12 weeks of age because after this age
passively acquired antibodies from the dam have usually declined below
levels which prevent successful immunization. When MLV vaccines are
given to pups that have lost their passively acquired antibody (~12
weeks of age), a single dose of vaccine can immunize. Multiple doses are
required for primary vaccination with certain killed vaccines (e.g. Leptospira
spp., Lyme disease) but single doses are sufficient when revaccinating
at a later time, usually at 1 year. Due to improvements in
multi-component core vaccines, especially the CPV-2 component, and the
lower antibody titers of dogs in vaccinated populations it is no longer
necessary to administer vaccines through the age of 18 to 20 weeks.
Previous recommendations for the last dose of vaccine at 18 or 20 weeks
were made in the 1980's and early '90's because CPV-2 vaccines failed to
immunize a high percentage of pups even when passively acquired antibody
titers were well below the level of antibody that provided protection
from infection with virulent virus. [3,6] Also at that time, a large
proportion of dogs had antibodies recently engendered by virulent virus,
rather than vaccines. The "window of vulnerability"
("critical period" - see Canine
Parvovirus, U. Truyen, In: Recent Advances in Canine Infectious
Diseases, L.E. Carmichael (Ed.), IVIS, Ithaca, NY - Doc. No.
A0106.0100), was as long as several months when certain of the older
CPV-2 vaccines were used! However, with the improved CPV-2 vaccines now
available from the major vaccine manufacturers, the "window of
vulnerability" has been reduced to 2 weeks, or less. It is,
therefore, not necessary to vaccinate pups beyond 12 to 14 weeks of age.
The other core vaccine components also will immunize a majority of dogs
when the last dose is given at 12 to 14 weeks of age. [6-8].
How Often to Vaccinate?
Repeated vaccinations with multi-component vaccines need not be repeated
at intervals more often than every 2 to 4 weeks in a puppy program. Two
to three doses of vaccine should be adequate to immunize when
vaccination is started at 6 to 9 weeks. The most important aspect of a
puppy vaccination program is to make certain that the last dose of
vaccine in the series is given when the animal is at least 12 to 14
weeks of age. However, as mentioned above, pups often receive 4 to 6
doses of the same multi-component vaccine during the first 3 - 4
months of life. The higher number of doses may be justified for animals
in humane shelters, commercial kennels, or other areas where animals are
at high risk. However, pet dogs in a single or multi-dog household are
at low risk of exposure to most diseases. Such animals would not need to
be revaccinated every 2 weeks and they should never be vaccinated every
week, as practiced in the USA by some breeders and veterinarians.
Furthermore, if a dog is at high risk of exposure to an important
disease like CPV-2, a monovalent CPV-2 vaccine is recommended, not a
multi-component product . The risk of adverse reactions has been greater
with multi-component vaccines.
Expected Immunization Success
Since passively acquired antibody declines below the level where it can
interfere with the current core vaccines by 12 to 14 weeks of age,
modified live CPV-2, CDV and CAV vaccines given at this age will
immunize a very high percentage of pups (>90%) and the immunity from
that single dose of vaccine will last for several years. Our research on
duration of immunity for the CPV-2, CDV and CAV vaccines has
demonstrated a minimum duration of immunity of 7 years; the maximum
duration of immunity may be for the life of most (>80%) vaccinated
animals. Many killed rabies vaccines have a minimum duration of immunity
of 3 years. However, a small percentage of pups (<5%) fail to develop
immunity to one or more of the core components and a much higher
percentage of pups (>25%) fail to develop immunity to certain of the
non-core vaccines for a variety of reasons. Reasons which have been
given include: The presence of passively acquired antibody at time of
last vaccination; delay in maturation of the immune system; poor
vaccinal immunogenicity; vaccine not given often enough; genetic
inability to respond to certain vaccine antigens; immunosuppression; too
many components in a multi-component vaccine; or ineffective lots of
To ensure that all pups become immune, one dose of rabies vaccine is
given at 12 weeks of age or older, followed by a second dose 1 year
later, or at 1 year of age. Revaccination is then done at 3 year
intervals. Similarly the CPV-2, CDV and CAV vaccine could be given at 1
year and then every 3 to 5 years without concern about loss of immunity.
There is no evidence, or reason, to believe that revaccination with the
core vaccines more often than recommended above would provide more
effective protection from the important diseases since the minimum
duration of immunity from the core vaccines is at least 3 years. States
in the USA which require annual revaccination for rabies should remove
those requirements because annual revaccinations are unnecessary.
Vaccinating the same animal less often also would reduce the risk of
adverse reactions. In areas where there is a high risk of rabies,
programs must be developed to immunize those dogs that have never been
vaccinated or have not been vaccinated within the past 3 or more years.
Unvaccinated dogs pose the greatest threat for the transmission of
rabies virus, not dogs which have been previously vaccinated or,
especially, those vaccinated within the past 3 years. In our studies,
pups vaccinated annually with modified live CPV-2, CDV and CAV vaccines
received no added benefit from annual revaccination throughout a period
of 7 years when compared to dogs that were vaccinated as pups then
challenged with virulent virus at 7 years of age. Both groups of dogs
were protected from challenge infection with CPV-2, CDV and/or CAV.
Therefore, for those vaccines that provide immunity for 3 or more years,
I believe that annual revaccination is contraindicated - the increased
risk of adverse reactions from revaccination provides no benefit. In
contrast, use of those products which provide only a short duration of
immunity (~1 year) requires annual, or even more frequent, vaccinations
- but only with products that contain vaccine components that are needed
in a particular region (e.g. Leptospira or Lyme disease bacterins),
not with multi-component products containing unnecessary vaccines.
"Non-Core" Vaccines: Which are Needed and When?
Which "non-core" vaccines are really needed? This question is
difficult to answer and depends on the animal and its environment.
Leptospira bacterins - The most important
"non-core" vaccine is for leptospirosis since this infection
can cause mild to severe illness and it is a zoonosis. The question
could be asked why Leptospira bacterins are not included as
"core" vaccines? The principal reason concerns vaccine
efficacy - a high percentage of vaccinated dogs do not develop
protective immunity, or they develop immunity for only a short duration
of time. Until recently, bacterins contained only two serovars (L.
canicola and L. icterohaemorrhagiae) and cross protection
between leptospiral serovars does not occur. Furthermore, the Leptospira
sp bacterins are among the more reactogenic components in
multi-component vaccines. Clinically, immediate and/or chronic
immune-mediated reactions have been observed and, experimentally,
multiple types of immune mediated hypersensitivities have been induced
with leptospiral antigens. Moreover, Leptospira bacterins do not
prevent infection or shedding of the organisms in the urine, even when
they reduce or eliminate the clinical signs of disease. Thus, the public
health threat from organisms being shed in the environment persists.
Finally, Leptospira bacterins are not considered "core
vaccines" because leptospirosis is rare in many geographic regions
of the USA and few or no clinical cases have occurred for many years.
Very recently, new vaccines have been licensed in the USA that contain L.
grippotyphosa and L. pomona. The new vaccines should provide
broader immunity and, hopefully, will prevent disease caused by those
serovars. However, the new vaccine containing the four serovars requires
evaluation in a large number of dogs before it is known whether it will
reduce the incidence of canine leptospirosis in endemic areas and if
adverse reactions are worse than those caused by current products which
contain only 2 serovars.
According to our recent survey on vaccination programs, approximately
30% of veterinary practices do not vaccinate for leptospirosis. The
responding practitioners either didn't believe that leptospirosis was a
significant problem in their area or the vaccine containing L.
canicola and L. icterohaemorrhagiae serovars failed to
provide protection. Also, there were concerns about adverse reactions
when the current products were used. Approximately 50% of the
veterinarians completing the survey must have felt leptospirosis was a
significant problem since they vaccinated >75% of the dogs with the
products containing L. canicola+icterohemorrhagiae. According to
our survey Leptospira bacterins were used in more dogs than any
of the other "non-core" vaccines except CPI.
Canine parainfluenza and B. bronchiseptica - CPI
is included as a component of all current parenteral vaccines containing
CDV, CPV-2 and CAV; therefore, it is given to every dog that receives
the core vaccine. Approximately 80% of practices surveyed vaccinated
less than 50% of dogs with B. bronchiseptica. The product used
most often for kennel cough was an intranasal vaccine that contained
both B. bronchiseptica and CPI. Many non-vaccinated dogs never
develop "kennel cough" or they develop mild, self-limiting
disease; however, other dogs, both vaccinated and non-vaccinated,
developed severe, protracted kennel cough requiring treatment. Efficacy
of the present kennel cough vaccines is controversial (see: Canine
Respiratory Bordetellosis, D. Keil and B. Fenwick, In: Recent
Advances in Canine Infectious Diseases, L.E. Carmichael (Ed.), IVIS,
Ithaca, NY - Doc. No. A0104.0100) and duration of immunity, if present,
would be less than 1 year. Ventilation and hygiene are important in
environments where kennel cough is prevalent. In certain kennels,
improvement in ventilation has eliminated or reduced the need for kennel
cough vaccines. Also, in some environments vaccination at intervals as
frequent as every 3 to 6 months failed to significantly reduce
Coronavirus vaccines - Although approximately 50% of
practices routinely use coronavirus vaccine, most vaccine experts agree
that this vaccine is not needed. Some experts consider CCV vaccines
useless. Clinical disease rarely occurs with CCV infection and when
disease does occur it is usually mild, self-limiting and most commonly
seen in pups less than 8 weeks of age - an age which is
earlier than vaccine would provide benefit. Based on our observations
that the preponderance of clinical cases caused by CCV occur in young
pups, any "protection" derived from vaccination of pups or
from natural infection would, in the practical sense, last a lifetime.
Furthermore, CCV alone has not been shown to experimentally cause
significant disease in susceptible dogs. The demonstration that CCV can
enhance the severity of disease caused by CPV-2, does not suggest a need
for CCV vaccine since dogs vaccinated with CPV-2 vaccine only, are
completely protected when co-infected with a combination of CCV and
CCV vaccine alone provided no protection for dogs challenged with a
combination of CCV and CPV-2.
Lyme Disease Vaccine - This vaccine
should be used only in areas where Lyme disease is known to occur, and
where it may pose a serious threat to the health of the dog. Even in
areas where Lyme disease has been shown to be endemic, and where
infection with Borrelia burgdorferi is common, clinical illness
is rare. When seen, it is often mild and readily treated with
antibiotics. In certain highly endemic areas where infection of the
natural vectors (mice and deer) is almost 100%, disease in dogs may be
more common, and sometimes severe, but cases are responsive to
After the release of the first human Lyme disease vaccine, a segment of
the human population with a particular human leukocyte antigen type,
determined by genetics, was found at increased risk to developing
chronic arthritis after vaccination with the Lyme vaccine. This finding
should signal caution in the over use of canine
Lyme vaccine since a similar phenomenon may occur in dogs. Lyme
disease vaccine, if used, should be given only to dogs that are
truly at very high risk of infection/disease.
Giardia vaccine - This relatively new product
may be valuable in a highly specialized market, mainly in larger
breeding kennels which whelp and raise many puppies. It is unlikely to
provide benefit as a routine vaccine. The effectiveness and safety of
the Giardia vaccine in those special situations where it is used
remains to be determined. Use of this vaccine would likely play an
insignificant role in reducing the public health concerns of human Giardia
The risks of adverse reactions from vaccines are not well studied, nor
are the adverse reactions rates well documented. Even where documented,
the information is not readily available. The immune mediated
hypersensitivities caused by vaccines are well known and occur in every
The most commonly observed hypersensitivity is a type I (immediate)
reaction which is most often caused by IgE antibody resulting in a local
or generalized anaphylaxis. The most common signs of local reactions are
facial edema, hives, itching and rarely sneezing; signs of a systemic
reaction include urination, vomiting, diarrhea, which is sometimes
bloody, dyspnea and collapse. According to a recent survey we have
conducted, the most common vaccination reactions observed in dogs
include pain, soreness, stiffness and/or lethargy at variable times
after vaccination. Swelling, a persistent lump, irritation, hair loss
and/or color change of hair at site of injection were also observed as
common reactions. A change of behavior was reported in a small
percentage of dogs after vaccination. Post-vaccinal neurologic disease
(e.g. encephalitis) was rare. All of the reactions noted above generally
occur within minutes, hours or days after vaccination; they were,
therefore, likely to have been associated with a vaccination. More
recently, it has been shown experimentally that dogs develop an
autoimmune response after vaccination, something that was known to occur
in other species .
Furthermore, a study of dogs in veterinary clinics showed a slight
increase in cases of autoimmune hemolytic anemia within 30 days
following vaccination with multi-component vaccines .
It is very difficult to document a "cause and effect"
relationship between vaccination and disorders occurring weeks to months
after vaccination, but it would not be unexpected for vaccines to
trigger immune-mediated disease (including autoimmune disorders) in a
small percentage of animals [4,
Adverse reactions from vaccines should not be used as a reason not to
vaccinate; instead, it is sensible not to use vaccines which are
unnecessary, or to vaccinate more often than needed. In general,
bacterial vaccines are more likely to cause immune-mediated reactions
than do viral vaccines. Killed vaccines, especially those which contain
adjuvants, are more likely to cause adverse reactions than do modified
live vaccines. Because immune mediated reactions are genetically
determined, some breeds, especially certain families of dogs, are at
much greater risk of developing adverse reactions than the canine
population as a whole .
Click on the reference number 
in the text . Click
here to view the complete list of references.
All rights reserved. This document is available on-line at
www.ivis.org. Document No. A0110.0500.