The onset of adverse reactions to conventional vaccinations
(or other inciting drugs, chemicals, or infectious agents) can be an immediate
hypersensitivity or anaphylactic reaction, or can occur acutely (24-48 hours
afterwards), or later on (10-45 days) in a delayed type immune response often
caused by immune-complex formation. Typical signs of adverse immune reactions
include fever, stiffness, sore joints and abdominal tenderness, susceptibility
to infections, central and peripheral nervous system disorders or inflammation,
collapse with autoagglutinated red blood cells and jaundice, or generalized
pinpoint hemorrhages or bruises. Liver enzymes may be markedly elevated,
and liver or kidney failure may accompany bone marrow suppression. Furthermore, recent vaccination of genetically
susceptible breeds has been associated with transient seizures in puppies
and adult dogs, as well as a variety of autoimmune diseases including those
affecting the blood, endocrine organs, joints, skin and mucosa, central nervous
system, eyes, muscles, liver, kidneys, and bowel. It is postulated that an
underlying genetic predisposition to these conditions places other littermates
and close relatives at increased risk.
In cats, while adverse vaccine reactions may be less
common, aggressive tumors (fibrosarcomas) can occasionally arise at the
site of vaccination. A recent study from Italy reported finding similar tumors
in dogs at the injection sites of vaccinations (Vascellari et al, 2003).
These investigators stated that their "study identified
distinct similarities between canine fibrosarcomas from presumed injection sites and feline post-vaccinal fibrosarcomas,
suggesting the possibility of the development of post-injection sarcomas
not only in cats, but also in dogs".
Additionally, vaccination of pet and research dogs with
polyvalent vaccines containing rabies virus or rabies vaccine alone was shown
to induce production of antithyroglobulin autoantibodies, a provocative and
important finding with implications for the subsequent development of hypothyroidism
(Scott-Moncrieff et al, 2002).
Vaccination also can overwhelm the immunocompromised
or even healthy host that is repeatedly challenged with other environmental
stimuli and is genetically predisposed to react adversely upon viral exposure.
The recently weaned young puppy or kitten entering a new environment is at
greater risk here, as its relatively immature immune system can be temporarily
or more permanently harmed. Consequences in later life may be the increased
susceptibility to chronic debilitating diseases.
As combination vaccines contain antigens other
than those of the clinically important infectious disease agents, some may
be unnecessary; and their use may increase the risk of adverse reactions.
With the exception of recently
introduced mutivalent Leptospira spp. vaccines,
the other leptospirosis vaccines afford little protection against the clinically
important fields strains of leptospirosis, and the antibodies they elicit
typically last only a few months. Other vaccines, such as for Lyme disease,
may be advisable only in those geographical areas where the risk of exposure
to Borrelia burgdorferi is significant.
Annual or biannual revaccination for rabies is required by some states even
though most USDA licensed rabies vaccine have a 3-year duration. Thus, the
overall risk-benefit ratio of using certain vaccines or multiple antigen
vaccines given simultaneously and repeatedly should be reexamined. It must
be recognized, however, that we have the luxury of asking such questions
today only because the risk of disease has been effectively reduced by the
widespread use of vaccination programs.
Given this troublesome
situation, what are the experts saying about these issues? In 1995, a landmark
review commentary focused the attention of the veterinary profession on the
advisability of current vaccine practices. Are we overvaccinating companion
animals, and if so, what is the appropriate periodicity of booster
Discussion of this provocative topic has generally lead to
other questions about the duration of immunity conferred by the currently
licensed vaccine components.
In response to questions posed in the first part
of this article, veterinary vaccinologists have recommended new protocols
for dogs and cats. These include: 1) giving the puppy or kitten vaccine
series followed by a booster at one year of age; 2) administering further
boosters in a combination vaccine every three years or as split components
alternating every other year until; 3) the pet reaches geriatric age, at
which time booster vaccination is likely to be unnecessary and may be unadvisable
for those with aging or immunologic disorders. In
the intervening years between booster vaccinations, and in the case of
geriatric pets, circulating humoral immunity can be evaluated by measuring
serum vaccine antibody titers as an indication of the presence of Aimmune memory@. Titers do not distinguish between
immunity generated by vaccination and/or exposure to the disease, although
the magnitude of immunity produced just by vaccination is usually lower
where vaccination is required by law, all animals, but especially those
dogs or close relatives that previously experienced an adverse reaction
to vaccination can have serum antibody titers measured annually instead
of revaccination. If adequate titers are found, the
animal should not need revaccination until some future date. Rechecking antibody titers can be performed
annually, thereafter, or can
be offered as an alternative to pet owners who prefer not to follow the
conventional practice of annual boosters. Reliable serologic vaccine
titering is available from several university and commercial laboratories
and the cost is reasonable (Twark and Dodds, 2000; Lappin et al, 2002;
Paul et al, 2003; Moore and Glickman, 2004).
Relatively little has been published
about the duration of immunity following vaccination, although new data
are beginning to appear for both dogs and cats.
study (Twark and Dodds,
valuated 1441 dogs for CPV antibody titer and 1379 dogs
for CDV antibody titer. Of these, 95.1 % were judged to have adequate CPV
titers, and nearly all (97.6 %) had adequate CDV titers. Vaccine histories
were available for 444 dogs (CPV) and 433 dogs (CDV). Only 43 dogs had
been vaccinated within the previous year, with the majority of dogs (268
or 60%) having received a booster vaccination 1-2 years beforehand. On
the basis of our data, we concluded that annual revaccination is unnecessary.
Similar findings and conclusions have been published recently for dogs
in New Zealand (Kyle et al, 2002), and cats (Scott and Geissinger, 1999;
Lappin et al, 2002).
Comprehensive studies of the duration
of serologic response to five viral vaccine antigens in dogs and three
viral vaccine antigens in cats were recently published by researchers at
Pfizer Animal Health ( Mouzin et al, 2004).
When an adequate
immune memory has already been established, there is little reason to introduce
unnecessary antigen, adjuvant, and preservatives by administering booster
vaccines. By titering annually,
one can assess whether a given animal=s
humoral immune response has fallen below levels of adequate immune memory.
In that event,
an appropriate vaccine booster can be administered.
• Dodds WJ. More bumps on the vaccine road. Adv Vet Med 41:715-732, 1999.
• Dodds WJ. Vaccination protocols for dogs predisposed to vaccine reactions. J Am An Hosp Assoc 38: 1-4, 2001.
• Hogenesch H, Azcona-Olivera J, Scott-Moncreiff C, et al. Vaccine-induced autoimmunity in the dog. Adv Vet Med 41: 733-744, 1999.
• Hustead DR, Carpenter T, Sawyer DC, et al. Vaccination issues of concern to practitioners. J Am Vet Med Assoc 214: 1000-1002, 1999.
• Kyle AHM, Squires RA,Davies PR. Serologic status and response to vaccination against canine distemper (CDV) and canine parvovirus (CPV) of dogs vaccinated at different intervals. J Sm An Pract, June 2002.
• Lappin MR, Andrews J, Simpson D, et al. Use of serologic tests to predict resistance to feline herpesvirus 1, feline calicivirus, and feline parvovirus infection in cats. J Am Vet Med Assoc 220: 38-42, 2002.
• McGaw DL, Thompson M, Tate, D, et al. Serum distemper virus and parvovirus antibody titers among dogs brought to a veterinary hospital for revaccination. J Am Vet Med Assoc 213: 72-75, 1998.
• Moore GE, Glickman LT. A perspective on vaccine guidelines and titer tests for dogs. J Am Vet Med Assoc 224: 200-203. 2004.
• Mouzin DE, Lorenzen M J, Haworth, et al. Duration of serologic response to five viral antigens in dogs. J Am Vet Med Assoc 224: 55-60, 2004.
• Mouzin DE, Lorenzen M J, Haworth, et al. Duration of serologic response to three viral antigens in cats. J Am Vet Med Assoc 224: 61-66, 2004.
• Paul MA.Credibility in the face of controversy. Am An Hosp Assoc Trends MagazineXIV(2):19-21,1998.
• Paul MA (chair) et al. Report of the AAHA Canine Vaccine Task Force: 2003
canine vaccine guidelines, recommendations, and supporting literature. AAHA,
April 2003, 28 pp.
• Schultz RD. Current and future canine and feline vaccination programs. Vet Med 93:233-254, 1998.
• Schultz RD, Ford RB, Olsen J, Scott F. Titer testing and vaccination: a new look at traditional practices. Vet Med, 97: 1-13, 2002 (insert).
• Scott FW, Geissinger CM. Long-term immunity in cats vaccinated with an inactivated trivalent vaccine. Am J Vet Res 60: 652-658, 1999.
• Scott-Moncrieff JC, Azcona-Olivera J, Glickman NW, et al. Evaluation of antithyroglobulin antibodies after routine vaccination in pet and research dogs. J Am Vet Med Assoc 221: 515-521, 2002.
• Smith CA. Are we vaccinating too much? J Am Vet Med Assoc 207:421-425, 1995.
• Tizard I, Ni Y. Use of serologic testing to assess immune status of companion animals. J Am Vet Med Assoc 213: 54-60, 1998.
• Twark L, Dodds WJ. Clinical application of serum parvovirus and distemper virus antibody titers for determining revaccination strategies in healthy dogs. J Am Vet Med Assoc 217:1021-1024, 2000.
• Vascellari M, Melchiotti E, Bozza MA et al. Fibrosarcomas at presumed sites of injection in dogs: characteristics and comparison with non-vaccination site fibrosarcomas and feline post-vaccinal firosarcomas. J Vet Med 50 (6): 286-291, 2003.
1. "Core" Vaccines *
Vaccines that every dog and cat should have
Table 2. Adverse
Reaction Risks for Vaccines *
is less risk associated with taking a blood sample
a titer test than giving an unnecessary vaccination."
Veterinary Medicine, February, 2002.
3. Titer Testing and Vaccination *
difficult to prove, risks associated with overvaccination
an increasing concern among veterinarians. These experts
antibody titer testing may prove to be a valuable tool in
determining your patients' vaccination
Veterinary Medicine, February, 2002.
4. Vaccine Titer Testing *
shows that once an animal's titer stabilizes,
it is likely to remain constant for many
Veterinary Medicine, February, 2002.