Vaccine Information For You And Your Pet

Important Vaccine Information for You and Your Pet

Vaccines for people and pets have been in the news quite a bit lately, for various reasons. New diseases to the United States like West Nile Virus and new threats from old diseases like smallpox have increased perceived need for vaccines, while concern about reactions to vaccines is driving sentiments in the opposite direction. There is a lot of new information, some mis-information, and much controversy regarding vaccination of people and pets alike.

Historically, vaccines have played a very important role (second only to improved hygiene and sanitation) in reducing contagious diseases in people and animals. Some of the most dramatic examples are Rabies in people and animals; distemper and Parvovirus in dogs; and smallpox, measles, and polio in people. These diseases were once common, but are now rarely seen where a large percentage of the population are immunized.

Vaccines work by introducing an individual’s immune system to a disease-causing organism without actually causing the disease. This allows the immune system to react quickly when confronted with the disease naturally. This can be done by presenting the immune system with weakened germs (polio in people, distemper in dogs), killed or inactivated germs (rabies for dogs, horses, and people, some Lyme disease vaccines for dogs); parts of germs (newer Lyme vaccines for dogs and Rabies vaccines for cats); or similar germs (early use of cowpox to prevent smallpox in people, measles vaccine to prevent distemper in dogs). Vaccines are often given by injection (diphtheria/pertussis/tetanus for children, distemper for dogs) but other routes are used as well. Oral vaccines are used for polio in humans, and an oral rabies vaccine has been used for wildlife to control an epidemic in Texas. Even nose or eye drops are used for some, such as Bordetella (kennel cough) in dogs, and some upper respiratory vaccines in cats.

Regardless the form or route, and despite the obvious benefits, vaccines do have some potential to cause harm to a patient. In the case of live vaccines, patients in rare instances can develop the actual disease, like with polio and some of the early canine parvovirus vaccines. Any type of vaccine has the potential to trigger an allergic reaction or inflammation at the injection site. And there is some speculation that repeated stimulation of the immune system may contribute to or exacerbate immune system disorders. These associations are difficult to prove or disprove, and research continues in this area.

Because vaccines have such an important positive role but also the potential for harm, every patient should be evaluated individually to assess benefits and possible risks. One current example is the increased risk with smallpox vaccines for people with heart disease. Vaccines shouldn’t automatically be given to every patient on an inflexible schedule; however, we do need to keep a high percentage of the population protected from important diseases to prevent epidemics from emerging.

At Hallett Veterinary Hospital, each patient’s history is evaluated to determine the need for the available vaccines, including any previous adverse effects from vaccines, and any previous medical conditions that would increase need or risk. A thorough physical examination is done to identify any current conditions that would influence decisions to vaccinate or not. Once all factors have been evaluated and medical concerns addressed, a decision regarding which vaccines should be given, and future vaccine schedule, will be made cooperatively between the pet owner and the veterinarian.

One option that exists to help this decision process is to perform a blood test to measure a patient’s immunity to a specific disease. This is called a "titer," or level of antibody present in the blood.

Titers are not foolproof, but can assist decision-making in specific instances. When antibodies are high, a patient is usually (but not always) well protected. However, a low antibody level does not necessarily mean a lack of immunity or a need for a booster. There are other branches of the immune system that can rapidly respond to infection even if antibody levels aren’t very high. Nonetheless, we may be able to avoid some un-needed boosters in patients with high antibody titers, especially those with a history of reactions to vaccines or other medical concerns.

Please call us at 569-0801 if you have any questions regarding vaccines for your pet, or any other pet-health concerns.


  • Contagious diseases
  • Titers