Why And How Are Pets Vaccinated

You have had vaccines, your pets have had vaccines, we have all had vaccines. But have you ever really pondered how or why they are given? 

Vaccines are administered to help prevent us and our pets from getting sick due to infection with common viruses, toxins and bacteria. Vaccines are also given to decrease the spread of disease. 

When you acquire a natural infection, like Chicken pox, your immune system begins to respond to the viral infection. The immune system learns how to defend itself against that disease and begins forming antibodies against the virus, antibodies attack and neutralize the infection. From that point on you have ‘immunity’ or antibodies that will attack and kill the virus should you be exposed to it again. The next time you are exposed, as long as your immune system is working properly, you will not become ill because your immune system has protected you. 

A vaccine works similarly, except the patient does not become ill. Vaccines are produced by taking a portion of the bacteria or virus or modifying the infective agent so that it will not make you sick. However, the modified infection is enough to trigger your immune system to respond. Sometimes there is a carrier or adjuvant that helps increase the immune response to the vaccine. Once the vaccine is administered, that bodies natural defense system, the immune system, is attracted to the injected material. Then the immune system begins to form antibodies against that disease. Basically the vaccine is teaching our bodies to develop immunity to a specific disease. The next time the vaccinated individual is exposed to that disease, the immune system jumps to their defense and prevents them from becoming sick. 

Vaccines infrequently cause reactions. Typical vaccine reactions can be soreness or swelling at the vaccine site. This is usually very brief, resolving in 24 hours. Patients may also experience fever and lethargy, this too may last only a few hours to a day. Even more infrequent are allergic type vaccine reactions where the patients face may swell and they develop hives and itching.Patients that have this type of reaction should be seen by their veterinarian and treated immediately. Typically, at our office, we suggest that patients that have vaccine reactions no longer receive vaccines since repeat exposure may result in even more severe vaccine reactions. Very infrequently, tumors can form at the site of the injection. This is seen in cats more than in dogs. Vaccines have been modified to to limit tumor formation and other reactions. Also, we have changed how we administer vaccines, giving them as far on the periphery of the pet as possible, so any tumor can be treated more effectively. 

In veterinary medicine our vaccines are typically given either subcutaneously (under the skin) or intranasally (liquid dripped or sprayed into the nasal passages). Unlike people, dogs and cats have loose skin and a large, subcutaneous (meaning under the skin)  space. Placing a vaccine or injection in this area is much less painful than an intramuscular injection (the type we humans commonly receive). It is very important that all vaccines be administered as far down on the leg as possible. Then, if there is a problem associated with the vaccine, it is not on the body where it may be more difficult to treat. This means that your pet may need to be gently restrained to be sure that vaccine is placed correctly. Subcutaneous vaccines may be a little more challenging to administer since it is easy to inject through the skin rather than under it! 

Intranasal vaccines are typically administered when we are vaccinating against respiratory illness, these vaccines are non-painful (no needles necessary), but the hardest part is convincing the patient to let us squirt a little liquid up their nose. 

We have become much more conservative in the use of vaccines in veterinary medicine. However, vaccines serve a vital function in limiting the spread and devastating consequences of many illnesses. The fact that rabies is an infrequent illness in pets and people in the United States is due to vaccines. Vaccines are the reason so many illnesses that were once common causes of death in our pets are  seldom seen.