How Often Should We Vaccinate Dogs?
Reviewer Fiona Hickford, BVSc, MVSc, DACVIM
Publication Citation
Title: Clinical use of serum parvovirus and distemper virus antibody titers for determining revaccination strategies in healthy dogs
Author: Twark L, Dodds WJ
Journal: J Am Vet Med Assoc
Volume: 217
Number: 7
Pages: 1021-1024
Date: 10/1/00
Purpose of Study
Background
Currently, a debate is ongoing regarding how frequently veterinarians
should administer booster vaccinations. Studies in cats have shown
that antibody titers against panleukopenia and respiratory (herpes
and calici) viruses remain high and that cats appear to be protected
(according to challenge experiments) for several years after vaccination.
For this reason, some veterinarians no longer vaccinate cats annually.
This has left veterinarians wondering what is an appropriate vaccination
interval for dogs.
Hypothesis
The objective of the study was to assess whether serum canine parvovirus and canine distemper virus antibody titers could be used to determine revaccination protocols in healthy dogs.
Study Design
Immunofluorescent antibody (IFA) titers against canine parvovirus
and canine distemper virus were determined in approximately 1400
serum samples from dogs of various ages. The date of most recent
vaccine administration was evaluated when available. A subgroup
of sera was tested by serum neutralization and hemagglutination
inhibition techniques, and the titers were compared with the IFA
results to determine a cut-off point at which the IFA titer could
be deemed protective.
Study Results
It was concluded that an IFA titer >/=1:5 was consistent with adequate antibody response. Approximately 95% of dogs had an adequate response to canine parvovirus and 98% had an adequate response to canine distemper virus. Approximately 93% of dogs still had adequate antibody titers against canine parvovirus and canine distemper virus >2 years after vaccine administration.
Commentary
Design Evaluation
The study design was not really appropriate to fulfill the objective
because dogs were not challenged with virus to prove protection.
Also, less than one third of the serum samples were accompanied
by information regarding the most recent vaccine administration;
therefore, a large amount of data was missing, so how could one
confidently determine an appropriate revaccination protocol? The
study basically validated an IFA for canine parvovirus and canine
distemper virus by comparing it to other techniques used to measure
the same antibodies at a reference laboratory. The "cut-off"
IFA titer, which implies protection, was determined by correlating
IFA titers with those from this reference laboratory and then
extrapolating from the laboratory's cut-off value. However, the
method by which the reference laboratory determined whether a
particular titer was protective was not described—was it
by challenge experiments? We must remember that although high
titers generally correlate with protection, humoral immunity is
merely one component of the immune system. Also, some dogs with
low titers still may be protected by cell-mediated immunity or
local immunity. Choosing a cut-off titer is not easy!
Results Evaluation
If one assumes that high antibody titers usually correlate with
protection, then it appears that most dogs are protected for more
than 2 years after vaccine administration; therefore, annual revaccination,
as typically recommended by veterinarians, may not really be necessary.
Clinical Application
Some pet owners and veterinarians may prefer to measure titers
before deciding whether to give booster vaccines. A word of warning:
each laboratory must standardize their own technique; they cannot
merely use cut-off titers from other laboratories.
Questions Raised
Does vaccine administration protect dogs against canine infectious
hepatitis and other components of typical combination vaccines
for dogs for >2 years? Data suggests that this is probably
not the case for leptospirosis.
Summary
This study showed that most dogs have high titers against canine
parvovirus and canine distemper virus for more than 2 years after
vaccine administration. Therefore, if one assumes that high antibody
titers usually correlate with protection, annual vaccination may
not always be necessary in dogs.
ISI Abstract
Authors
Dodds, WJ
Article Title
Clinical use of serum parvovirus and distemper virus antibody
titers for determining revaccination strategies in healthy dogs
Abstract
Objective-To assess whether serum canine parvovirus (CPV) and
canine distemper virus (CDV) antibody titers can be used to determine
revaccination protocols in healthy dogs. Design-Case series. Animals-1,441
dogs between 6 weeks and 17 years old. Procedure-CPV and CDV antibody
titers in serum samples submitted to a commercial diagnostic laboratory
were measured by use of indirect fluorescent antibody (IFA) tests.
On the basis of parallel measurements of CPV and CDV serum antibody
titers in 61 paired serum samples determined by use of hemagglutination
inhibition and serum neutralization methods, respectively, we
considered titers greater than or equal to 1:5 (IFA test) indicative
of an adequate antibody response. Results-Age, breed, and sex
were not significantly associated with adequate CPV- or CDV-specific
antibody responses. Of 1,441 dogs, 1,370 (95.1%) had adequate
and 71 (4.9%) had inadequate antibody responses to CPV, whereas
1,346 of 1,379 (97.6%) dogs had adequate and 33 (2.4%) had inadequate
responses to CDV. Vaccination histories were available for 468
dogs (468 for CPV, 457 for CDV). interval between last vaccination
and antibody measurement was 1 to 2 years for the majority (281/468;
60.0%) of dogs and 2 to 7 years for 142 of 468 (30.3%) dogs. interval
was < 1 year in only 45 of 468 (9.6%) dogs. Conclusions and
Clinical Relevance-The high prevalence of adequate antibody responses
(CPV, 95.1%; CDV, 97.6%) in this large population of dogs suggests
that annual revaccination against CPV and CDV may not be necessary.
Reprints
DODDS WJ,HEMOPET & ANTECH DIAGNOST,;17672A COWAN AVE;IRVINE,CA
92614 USA.
Research Institutions
Hemopet & Antech Diagnost, Irvine, CA 92614 USA.
Source
JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION,217: (7)
-1024 OCT 1 2000
Document Type
Article
Language
English
Discipline
A VETERINARY MEDICINE/ANIMAL HEALTH
IDS No.
357ZG
Publisher
AMER VETERINARY MEDICAL ASSOC
ISSN/ISBN
0003-1488
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