What is the immune system? Why is it important? The immune system plays a pivotal role in maintaining your pet’s health. One of the most important functions of this highly complex system of specialized cells and molecules is to protect pets from disease and infection caused by foreign invadersâ€”viruses, bacteria and a host of other microbes and parasites intent on assaulting the body and causing disease.
What does vaccination accomplish? Vaccines are given to prepare the body’s immune system against invasion by particular disease-causing organisms. Vaccines contain antigens which to the immune system “look” like the organism but don’t, ideally, cause disease. When the vaccine is introduced by injection or by some other means, the immune system responds by mounting a protective response. When your pet is subsequently exposed to the organism, the immune system is prepared and either prevents infection or reduces the severity of disease.
Why do young animals require a series of vaccinations? Young animals receive antibodies from colostrum (the first milk the mother produces) that is ingested during the early hours after birth. Maternal antibodies help protect against infectious disease until the youngster’s own immune system is more mature. Unfortunately, maternal antibodies also interfere with the vaccine’s ability to stimulate the youngster’s immune system. To counteract this problem, veterinarians often administer a series of vaccines, usually beginning when the youngster is around six to eight weeks of age, and then repeating the vaccination at three to four week intervals until maternal antibodies have waned, usually at around twelve to sixteen weeks of age. In some cases (e.g., rabies vaccine) the initial vaccine is not given until maternal antibodies have altogether disappeared.