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M. Day1
1WSAVA, Vaccination Guidelines Group, Cheddar, United Kingdom
Chairman, WSAVA Vaccination Guidelines Group
Global Canine Vaccination Guidelines
There are two sets of canine vaccination guidelines available: those produced by the American Animal Hospital Association [1] and those from the WSAVA VGG [2-4]. The fundamental principle of both sets of guidelines, as encapsulated by the VGG, is that ‘We should aim to vaccinate every animal with core vaccines. Non-core vaccines should be given no more frequently than is deemed necessary.’
The WSAVA guidelines suggest that we should
aim to vaccinate MORE animals. This relates to the phenomenon of ‘herd immunity’. Herd immunity suggests that where a minimum proportion (for example 75%) of a herd of animals is vaccinated, it is difficult for an infectious disease outbreak to occur in that herd. The ‘herd’ for the canine practitioner is the population of dogs living within his or her practice area – and our aim should be to have as many of these animals vaccinated as possible, in order to reduce the chances of disease outbreak in the herd. This is particularly important in
the context of canine rabies. Where a mass vaccination campaign results in at least 70% of the dog population receiving vaccine, there is marked impact on the prevalence of canine and human rabies.
In order to apply the principles of vaccination guidelines, it is firstly necessary to understand the definitions of ‘core’ and ‘non-core’ vaccines. CORE vaccines are those that all animals should receive to protect them against potentially lethal diseases of global significance or where legislation may dictate [i.e. canine rabies]. The use of NON-CORE vaccines in certain animals is dictated by geographical location, lifestyle and exposure risk. Some vaccines are NOT RECOMMENDED because there is little scientific justification for their use.
For dogs, the core vaccines are those that protect
against canine distemper virus (CDV), canine adenovirus (CAV) and canine parvovirus-2 (CPV). In any country
in which rabies is an endemic disease, then rabies vaccination is also considered core for dogs. Non-core canine vaccines include those that protect against leptospirosis, canine parainfluenza virus (CPi), Bordetella bronchiseptica and Borrelia. Canine coronavirus (CCV) vaccine is not recommended as there is little evidence that CCV is a primary enteric pathogen or that the vaccine can protect against such infection. The WSAVA global guidelines do not consider some vaccines that have very restricted geographical availability (e.g. vaccines against canine herpesvirus, Leishmania or Babesia).
WSAVA guidelines provide generic advice to practitioners, but it is impossible to ensure that the guidelines are tailored to best fit the local situation in each of the 86 WSAVA member countries. The VGG encourages national associations to adapt and modify the guidelines for local use where appropriate. This process might involve altering the classification of a vaccine. For example, in the UK, Leptospira vaccine is generally considered core for the dog and attempts are now being made to provide data that define disease prevalence and characterize locally circulating serovars [5].
Core Vaccination of Puppies
The vaccination of puppies is determined by the transfer of maternally-derived antibody (MDA) from the bitch
in colostrum. This antibody is crucial for protection of the pup during early life, but simultaneously blocks the endogenous immune response of the puppy to core vaccination with most available modified live virus (MLV) vaccine products. Canine immunoglobulin has a half
life of around 11 days and there is progressive decline
in MDA concentrations in pups over the first weeks of life. The ‘window of susceptibility’ occurs when there
is no longer sufficient maternal antibody to provide full protection from infectious disease, but where sufficient antibody remains to block the ability of the pup to
make its own immune response to MLV core vaccine. Traditionally, this window has been taken to occur at between 8 – 10 weeks of age, but new evidence shows that higher titre vaccines increase maternal antibody concentrations leading to persistence of MDA for longer periods of time. Studies have now shown that around 1 in every 10 puppies has ‘blocking’ levels of MDA against CPV at 12-14 weeks of age. For this reason, vaccination guidelines now recommend that puppy vaccination (with MLV core vaccines) starts at 8 – 9 weeks of age, with
a second vaccine 3 – 4 weeks later and a third vaccine given at 16 weeks of age or older. The puppy protocol now includes a fourth core vaccine, which optimally
An Urban Experience

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