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  • Fabiola Frederico

VACCINE FAILURE & WHAT CAN BE DONE ABOUT IT

IMMUNIZATION & IMMUNITY IN PUPPIESThe terms immunization, vaccination, and inoculation are often used interchangeably, but the terms technically have slightly different definitions. "immunization is the process whereby a puppy is made immune or resistant to an infectious disease, typically by the administration of a vaccine. Vaccines stimulate the body’s own immune system to protect the puppy against subsequent infection or disease. A puppy becomes immune to a disease when the body has been exposed to it either through illness or vaccination. The immune system develops antibodies to the disease so that sickness cannot happen again.


Immunization describes the actual changes the body goes through after receiving a vaccine. A vaccine as "a product that stimulates the immune system to produce immunity to a specific disease, protecting from that disease. Vaccines are usually administered through needle injections, but can also be administered by mouth or sprayed into the nose.

Vaccination is the process of getting a vaccine into the body or "the act of introducing a vaccine into the body to produce immunity to a specific disease." A vaccine is what initiates the immunization process.


Inoculation

The definition of inoculation is "to give a person or animal a vaccine—a substance to prevent a disease." Inoculation is simply the process of giving a person a vaccine.



When a vaccinated dog develops the disease against which she was vaccinated, it is often refereed to as vaccine failure. In most cases however it is not the vaccine that has failed but rater it was an inadequate immune response to the vaccine. Listed below are some of the main reasons disease may occur in vaccinated dogs.

Maternal Antibody

Newborn puppies receive disease protection from their mother thought the transfer of antibodies. These antibodies are transferred from the mother through the placenta and through colostrums, the first milk the newborns receive. Antibodies are small disease fighting proteins produced by certain types of cells called B cells . The proteins are made in response to foreign particles such as bacteria or viruses. These antibodies bind with certain proteins antigens on foreign particles like bacteria, to help inactivate them.

The age at which puppies can effectively be immunized is proportional to the amount of antibody protecting the young animals received from their mother. High levels of maternal antibodies present in a puppys bloodstream will block the effectiveness of a vaccine. When the maternal antibodies drop to a low enough level in the puppy immunity protection from disease can be produced through vaccination.

The antibodies from the mother generally circulate in the newborns blood for a number of weeks. There is a period of them from several days to several weeks in which the maternal antibodies are too low to provide protection against the disease, but too high to allow a vaccine to work. This period is called the window of susceptibility is different in every litter and between animals in the same litter.

A vaccine does not immediately provide protection. It takes several days to a week or more for an animals body to respond to the vaccine. A young animal is susceptible to a disease if it is exposed to the disease before a vaccination has had time to stimulate the body’s immunity. Too short of an interval between vaccination and exposure to disease can result in the dog developing the disease. In some cases the same is true if the length of time between vaccination and exposure to disease is too long.

Using a High titer, low passage vaccine can stimulate active immunity in the young pup even when maternal antibodies are present. This modified live vaccine contains a higher number of virus particles, high tier which are less attenuated low passage than average vaccines. Another type the recombinant vaccine is made from portions of the gens of the virus or bacteria


Using CAVIDS Titer Testing , and canine nomograph can give us the best timing to vaccinate our puppies and follow up to check the individual pups immune response to the vaccine.

Canine Nomograph – What is it?

A nomograph is an estimate of the amount of antibody passed to a litter of pups from the mother via her colostrum. During the puppy’s first hours of life, its intestinal tract is able to allow colostral antibody to be absorbed into the bloodstream. This passive antibody helps to protect the newborn from all the diseases that the mother is protected from. As the puppy grows up, maternal antibody breaks down in approximately 2 week “half lives” until it is no longer present in the pup. While this antibody is at higher levels, it is able to neutralize viruses such as canine parvovirus and canine distemper virus. Because of this neutralization, puppy vaccine can be blocked. Maternal antibody interference is one of the most common causes of vaccine failure to immunize! The reason that puppies are given multiple doses of vaccine is because most of the time we don’t know what their maternal antibody titers are, and so don’t know when the vaccine will be effective. Nomograph testing helps us understand the best timing of vaccination to assure a litter will be effectively immunized. Because the nomograph is limited by the ability of the dam to make colostrum and for the pups to receive it, nomograph results should not be used as a definitive indication of protection from disease.

  1. It is highly recommended to test puppies to ensure they have become immune after their initial vaccination(s). The biggest risk factor for failure of vaccine to immunize is when vaccine is neutralized by antibody that the puppy received passively from the mother at birth. While this maternal antibody is above a certain level, it will neutralize the infectious virus in modified live vaccines, just as antibody does when actively produced by an immune animal. However, maternal antibody is not actively being made by the puppy or kitten itself. With time, it is metabolized and disappears, leaving the puppy susceptible to infection. Puppy vaccines are given multiple times in order to be sure to catch the right moment when the vaccine virus can infect the puppy to do the job of immunizing her. If that moment is missed, the puppy goes through months of disease susceptibility until vaccination at one year induces immunity. It is much preferable to discover lack of immunity as soon as possible through titer testing rather than to find this out the hard way!


Often we do not know what level of antibody the mother may have passed to her pups. In that case, the puppy series of vaccinations should be continued until 16 weeks of age, with titer testing completed 2 weeks later at 18 weeks of age. An in-clinic “yes/no” test can be used instead of titer testing, but this must wait until the puppy is 24 weeks of age or older since this test cannot differentiate between active and passive immunity as well as quantitative tests can.

However, when a nomograph has been completed to determine the titers of the dam of a litter, we are able to determine conservatively when that antibody will be dissipated and no longer present to interfere with vaccination or with titer testing. We are able to “do the math” to determine active responses in the young vaccinate, sometimes at quite young ages when dam titers are low. When we know the amount of antibody the mother has, we can titer test the puppy at an age uniquely tailored to the litter. Confirming immunity in a young puppy allows the new family to have peace of mind during critical early socialization periods, such as puppy kindergarten.


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