Vaccines have been used for hundreds of years, and continue to save lives every day. Most vaccines are either killed vaccines, or modified live vaccines. Killed vaccines are made by taking the disease organism (virus or bacteria) to be vaccinated against, killing that organism, and then administering it into the animal that is to be protected. Modified live vaccines are made by inactivating the dangerous parts of the bacteria or virus that is to be vaccinated for, then administering it to the animal.
There are many different ways that vaccines can be administered. Most commonly vaccines are administered under the skin. Other commonly used routes are into the nose or mouth.
When vaccines are administered to an animal or person, they stimulate the body’s immune system. The body reacts by making antibodies and many other protective things in the body. By exposing the animal to a non-disease form of the infectious agent (virus/bacteria), the body can prime itself to be ready if exposure to the actual disease occurs. As long as the vaccine has been in the body long enough to generate an immune response (generally days to a couple weeks), the animal is usually protected against whatever it was vaccinated against.
Upon exposure to the infectious organism, since the body is already primed from the previous vaccine, the animal is able to fight the disease better. Most vaccines work to prevent disease, so in many cases, no signs of sickness are seen. Other vaccines work to decrease disease, so although sometimes mild clinical signs are seen, they are not nearly as severe as those seen in non-vaccinated animals.
In a herd of animals, it is possible that an occasional animal will not develop a complete immune response to the vaccine, and if exposed to the infectious organism, may develop disease although it has been vaccinated. Its vaccinated herdmates that have responded well to the vaccine work to help prevent disease spreading to the animals that have not developed a complete immune response. This is called ‘herd immunity’ and works not only in animals, but also in people. Herd immunity also works to protect those animals and people that cannot be vaccinated due to some reason or another.
Preventative medicine is key to helping decrease sickness, and vaccines play a very important part in preventing disease. Whether it be a herd of cattle or horses, or an individual dog or cat, certain vaccines may be helpful in keeping your animals as healthy as possible. If you have questions regarding which vaccines are right for your animals, speak to your veterinarian.
Dr. Corinna Goodine was born and raised in the Fort St. John Community and discovered her passion for veterinary medicine at an early age. In June 2015 she completed her dream of becoming a veterinarian and graduated from The Western College of Veterinary Medicine. She is excited and enthusiastic about joining the veterinary team as a mixed animal practitioner with special interests in beef cattle and small animal medicine and surgery.