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Why Does a Chihuahua Receive the Same Dose of Vaccine as a Great Dane?

Why Half Dose Vaccinations Are a Bad Idea


                We have had a few questions here and there about why small dogs don’t receive a smaller dose of vaccine or why they can’t receive half dose of vaccines.  In truth, half dose vaccines do not make any sense.  We will explore a basic notion of how a vaccine works and why the volume of vaccine has no bearing on safety of vaccine and does not prevent vaccine reaction.  Failing to give the full dose may also prevent your pet from building proper immunity thus leaving him unprotected against disease. 

                What does a vaccine do?  A vaccine is intended to stimulate the body’s immune system to create antibodies to protect it should the same virus or bacteria attack again. 

                Why does a five pound patient receive the same dose as a 150lb patient?  The volume of the vaccine has little to do with whether or not it will produce side effects.  All mammals, regardless of size, have lymph nodes in their bodies.  Lymph nodes contain groups of cells in the middle known as germinal centers.  The germinal center contains lymphocytes responsible for creating immunity.  These germinal centers are roughly the same size in each node relative to the size of the animal.  So, regardless of the size of the patient, the same vaccine volume is needed to induce the germinal center to produce immune cells.

                If a dog were to be given only a half dose of vaccine, it may not stimulate the germinal center enough to produce immunity, and, worse, it does not mean the patient cannot still have a reaction to the vaccine.  Only one study was done to see if a lower volume created proper immunity and this study was flawed using only a small number of previously vaccinated adult dogs.  All the dogs showed a good vaccine titer after receiving a half dose vaccine, but, since they were previously vaccinated, it was likely that they still had existing immunity. 

                Half dose vaccines are bad medicine.  They neither prevent vaccine reactions nor provide adequate immunity against disease.  While we aim to prevent over-vaccination and limit adverse reactions, there is no benefit to using a smaller volume vaccine, and we do not support this practice.

                This blog brought to you by the Patton Veterinary Hospital serving Red Lion, York and the surrounding communities.

Source:  https://www.cdc.gov/vaccines/hcp/conversations/downloads/vacsafe-understand-color-office.pdf

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