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 Vaccine Issues:

There are 3 types of vaccines and depending on the type generally determines whether boosters are necessary or not.  Vaccines are either modified live (MLV), killed or recombinant.  The first two are most common.

MLV are more like the original pathogen in the way they elicit an immune reaction. In general, vaccines that contain the living organisms will produce a stronger and a longer-lasting immunity, but their virulence is reduced to a safe level (attenuated). Once MLVs are introduced into the body they elicit the expected immune response, but die rapidly and rarely cause the disease.  MLVs can shed vaccinal virus into the environment which can be a risk for unvaccinated animals or immunocompromised animals.  Examples of MLVs are Canine Distemper, Canine Parvovirus, Canine Adenovirus and Canine Parainfluenza.

Killed or inactivated vaccines are safer because unlike the MLVs they do not shed virus into the environment nor can they cause the illness they are supposed to be preventing. However, in order to maximize their effectiveness, killed vaccines often have adjuvants in them.  Adjuvants stimulate an inflammatory response to increase the immune response. Killed vaccines also may have remnant chemicals which were used to kill the bug so one can see reactions from the chemicals or the adjuvant, but one can not get the infection from a killed vaccine.  Killed vaccines don’t tend to stimulate the immune system as much as MLV so booster doses for killed vaccines are often required.  Examples of killed vaccines are Rabies, Canine Influenza, Canine Coronavirus, Lyme, Bordatella, Leptospirosis.

In a recombinant vaccine, the “bug” has had its genetic material artificially modified. This modification usually involves deletion of all or part of some genetic material or the insertion of one or more genes from another organism. USDA has classified three different types of recombinant vaccines - subunit, gene-deleted and vectored.  Examples are Merial’s distemper, canine parvo, corona and lyme vaccine. 

When determining which vaccine, the type of vaccine, when to start vaccination in a puppy and frequency of vaccination (if boosters are required), one needs to look at several factors and discuss them with your veterinarian:

(1) Environmental exposures – where the dog lives (what bugs are endemic like Lyme in deer infested areas of NE USA), where the dog goes (shows all over the country vs backyard pet that is generally always home);

(2) Breed of dog – some breeds are either oversensitive to a type of vaccine or its adjuvant and some breeds develop poor immunity to a particular vaccine, likely genetic in nature.

(3) Amount of passive immunity the puppy receives (in utero and from colostrum) – orphaned pups will likely need vaccination sooner than pups that got colostrum.

(4) Laws regarding vaccination (i.e. USA laws requiring rabies vaccine).

(5) Health of dog – immunocompromised or sick dogs – these dogs are vaccinated differently or their vaccinations are delayed.

Why do some vaccinated pups get the illness from the vaccine that was supposed to prevent it? There are several possible reasons that can negatively impact on the effectiveness of vaccines: (1) maternal antibody interference; (2) stress, such as flying a dog immediately after vaccination; (3) animal has poor immune system (3) parasites or other concomitant illnesses; (4) poorly handled, stored or administered vaccine; (4) vaccines give too close together or given too far apart; (5) variant stains not covered in the vaccine.  (6) owners assumption that the vaccination infers immediate immunity and takes the dog to a high risk area.  I’m sure there may be others.

Properly administered vaccination for humans or dogs is not an absolute or sure thing.  No vaccine produces 100% protection all of the time.  All dogs are not the same, they have differently functioning immune systems that respond differently to vaccines.   Please do your own research for your own dogs.  Rely on evidence-based information, like vaccine studies, studies regarding titer testing.  Your vet should be willing to help you locate this type of information which will help in making the right decisions for your dogs.

Information present in the scientific literature suggests that parvo’s CPV-2c (aka F-strain) is very similar genetically to CPV-2a and CPV-2b; and, that vaccines developed prior to the discovery of CPV-2c protect dogs from the CPV-2c challenge.  This new 2c strain seems to be more virulent with faster onset of symptoms so any inkling of parvo, seek medical care immediately for supportive care.

For more information about vaccines please contact me.