Download VACCINATION – THE FACTS

UK KENNEL CLUB: VACCINATION ADVICE SHEET
Over the past decades, vaccination has had major impact on the prevalence of lifethreatening infectious disease in the canine population. More recently, just as in
human vaccination, there have been changes in advice given related to the vaccine
components administered and the frequency of administration. These changes have
affected vaccination schedules for puppies and adult dogs. This document aims to
explain the importance of vaccination and the way it is currently practiced for the dog.
Puppies can receive their first vaccination from approximately 8 weeks of age. The
reason that vaccination cannot be started any earlier relates to the fact that newborn
puppies obtain protection from infection through the ‘first milk’ or colostrum. The
colostrum is enriched with protective antibodies from the bitch (maternally-derived
antibody or MDA) that is crucial for providing protection, but also prevents the pup
from mounting its own protective immune response until such time as the MDA has
gone (maternal antibodies gradually disappear until they are all gone by around 1416 weeks of age). The presence of inhibitory MDA, which may vary in amount
between individual puppies, is the reason why it is necessary to give repeated
vaccines to very young animals.
The vaccines that are given, and their frequency of administration, will vary
depending on the normal practice of your veterinary surgeon. Your veterinary
surgeon will start your puppy on a course of vaccinations against the three main
infectious diseases: canine distemper (caused by canine distemper virus;
CDV), hepatitis (caused by canine adenovirus; CAV-1) and parvovirus (caused by
canine parvovirus; CPV-2). In the UK most veterinary surgeons will also advise
vaccination against leptospirosis (caused by a bacterium – Leptospira). Current
vaccines against hepatitis are based on use of CAV-2, which protects against
hepatitis, but also respiratory disease caused by CAV-2. For parvovirus, CPV-2
variants are those currently circulating amongst the canine population. The vaccine
against the three viral diseases (referred to as a CORE vaccine) is a combination
product and the Leptospira vaccine (referred to as a NON-CORE vaccine) is
separate.
In order to ensure development of immunity, puppies require a series of early-life
vaccines together with a booster vaccination given either at 1 year of age or 12
months after completing the puppy series. Current recommendations of Vaccination
Guidelines Groups (see later) is for a first CORE vaccination at 8 – 9 weeks of age, a
second 3 – 4 weeks later and a third given between 14 – 16 weeks of age (followed
by the booster 12 months later). The Leptospira vaccine may be started later than
those for the CORE diseases and must be given as two injections, 3 – 4 weeks apart,
followed by a 12 month booster.
Your veterinary surgeon may also elect to use a vaccine that provides additional
protection against other NON-CORE agents, such as those that contribute to the
development of upper respiratory tract disease in the dog (canine parainfluenza virus
[CPi] and the bacterium, Bordetella bronchiseptica).
All of the CORE diseases and leptospirosis can be fatal, so after its first course of
vaccinations, the dog will need re-vaccinating no more frequently than every 3 years
for CORE components (CDV, CAV-2 and CPV-2) and annually for leptospirosis. The
difference between the CORE and NON-CORE vaccines in how frequently they are
administered to adult dogs relates to the way in which the vaccines work (see below)
and the period of time for which they are known to protect the animal (called the
‘duration of immunity’ or DOI). For CORE vaccines the MINIMUM duration of
immunity is at least 3 or 4 years and likely much longer. Your veterinary surgeon can
now use a simple test kit to determine whether your dog has protective immunity to
the CORE vaccine-preventable diseases and whether it requires revaccination. For
NON-CORE vaccines, the DOI is only 1 year and annual revaccination is still
necessary if these products are used. Keep vaccination certificates safe as you may
need to show them at boarding kennels, dog-training classes or if you take your dog
abroad (when a pet passport will also be required).
Until your puppy is fully vaccinated at 14-16 weeks, you should ideally not take it
anywhere where it might come into contact with dogs or ground that may be infected,
but you can take it out in your arms or the car to get it used to different places and
situations. Even if a puppy has been vaccinated at 8 and 10 weeks using a so-called
‘early finish’ protocol, it may not be fully protected until receiving the third vaccination
at 14-16 weeks. This is because in around 10% of puppies, the antibody received in
the colostrum from the mother (MDA) can still block responses to vaccination up to
12 weeks of age. Early socialization of puppies has great behavioural benefit, but if
you attend a ‘puppy class’ you should ensure that all of the participants are
vaccinated and that it is held in an environment where there is minimal risk of contact
with infectious agents.
How does vaccination work?
The immune system is the body’s defence mechanism against infectious disease.
The body recognises invading viruses and bacteria as ‘foreign’ and its reaction to
these ‘foreign invaders’ is called an immune response. The body produces antibodies
which destroy or remove the foreign substances.
The essence of vaccination is that it makes use of the body’s natural systems for
fighting disease. This is done by presenting a substance (the vaccine) to the body
which mimics a disease, but does not actually cause the disease. In dogs the
vaccine can be introduced by injection or by intranasal delivery (to protect against
agents that contribute to upper respiratory tract disease).
The body prepares its immune response, which then is activated if that disease is
detected at some time in the future. The immune system of the body has memory,
especially for diseases prevented by CORE vaccines. This memory can prevent
those CORE diseases in an animal protected by previous vaccination. Vaccination is
the most important way to prevent certain diseases. The immune system is
continuously active in defence against disease and vaccination simply amplifies or
augments this system of defence.
How do diseases spread?
All living organisms share the genetic drive to make sure that their species continues
to exist. This applies to viruses and bacteria as much as to man and animals.
Disease-causing organisms therefore have built into their structure the ability to
spread from one susceptible organism to another. They can be transferred from host
to host by physical contact, contact with body fluids, by the consumption of diseased
food, transferred by a ‘third party’ vector (i.e. mosquitoes, fleas, ticks or midges) or
they can be airborne, requiring proximity, but no physical contact to jump from host to
host. Some diseases are specific to one animal species, while others can infect, or
are carried by, a range of species.
Does vaccination have any side effects?
Anybody who has ever been vaccinated knows that it can occasionally make you feel
quite feverish and poorly for a short while. Whilst this effect is not pleasant, it is a
sign that the vaccine is stimulating the body’s disease defences. The vaccine may be
expected to cause those effects as it stimulates an immune response and this is
simply an indication that the vaccine is working and should not be a matter of
concern. Exceptionally, there can be more severe side effects, but they are so rare
that the benefits obtained with CORE vaccination far outweighs the risks of not being
protected from life-threatening infectious diseases.
What are the different types of vaccines?
A vaccine must stimulate an immune reaction in the recipient, similar to the immune
reaction that the real disease would produce, but the vaccine must not actually cause
the harmful effects of that disease. The manner in which the vaccine component is
processed in the laboratory is intended to make it safe, but sufficiently similar to the
disease so that the body recognises it. There are two broad techniques that are
used:
 Infectious: a weak or ‘attenuated’ form of the disease-causing agent (virus or
bacteria) is grown in the laboratory which, when injected into an animal, does
not have the power to cause actual disease but causes a mild infection
(without signs) in order to stimulate immunity.
 Non-infectious: the disease organism or parts of the organism in the vaccine
are not infectious, but they are able to stimulate immunity sufficient to prevent
disease or reduce the severity of disease.
Both types of vaccines (infectious and non-infectious) have their advantages and
disadvantages. There are also new genetically modified vaccines available. Such
vaccines have the ability to better target the type of immunity required and provide
new exciting possibilities in disease control.
How frequently should vaccines be used?
Vaccination plays a very important role in the control of infectious diseases. Whilst it
is recognised that adverse reactions such as an allergic response or a lack of
efficacy (the vaccine fails to protect from the infection) may occasionally occur, an
analysis of the overall benefits and risks strongly supports the continued use of
vaccination.
Your veterinary surgeon should make a thorough assessment of the benefits and
risks on an individual case basis and discuss them with you when deciding the timing
of vaccination and the use of particular vaccines. Your veterinary surgeon will use
various sources of information to decide the frequency of vaccination, including the
manufacturer’s data sheet and scientific guidelines that are made available by
professional bodies (e.g. the WSAVA Vaccination Guidelines Group, the American
Animal Hospital Association and the American Association for Feline Practitioners).
Veterinary surgeons will use vaccines in accordance with current scientific
knowledge and what they know of the prevailing disease trends in their area.
What are the benefits of vaccinating dogs?
There is no doubt that the use of vaccination has been of huge benefit to our pets by
bringing some very significant diseases under control The use of ‘combination’ or
‘multivalent’ vaccines (where several different vaccines are given together) has
transformed the control of many diseases of dogs. Virus diseases such as those
caused by CDV, CAV-1 and CPV-2 used to be scourges. The development of
vaccines and their widespread use has brought the diseases in question under
control.
The way in which vaccines are used in dogs is no different to the way in which they
are used in human populations. When the uptake of vaccination by responsible dog
owners who wish to prevent their pet from catching certain diseases is sufficient it
may reduce the amount of infectious disease circulating amongst dogs in that
geographical area. The vaccine has therefore produced ‘herd immunity’, which is an
ideal situation for disease control. It is much better to prevent infection with CDV,
CAV-1 and CPV-2 than to attempt to treat the diseases caused by these viruses,
since they are often fatal.
ACKNOWLEDGMENT
This information sheet has been prepared in collaboration with the WSAVA
Vaccination Guidelines Group. A detailed information document on canine and feline
vaccination for owners and breeders of dogs and cats may be accessed from the
Vaccination Guidelines Group page on the WSAVA website:
http://www.wsava.org/VGG1.htm