Vaccines contain viruses, bacteria or other disease-causing organisms that have been killed or altered so that they can no longer cause disease. Newer vaccines may contain genetically engineered components derived from those disease agents. When given to an animal, vaccines will stimulate the body's immune system to form disease fighting cells and proteins (known as antibodies) to protect against the disease. Although the protection afforded by vaccines can be reduced by poor health and poor nutrition, most vaccinated animals will be resistant to the disease for which they are fully vaccinated.
How are Vaccines Given?
Most vaccines are given by injection, either under the skin or into the muscle. Some vaccines may be administered as drops into the nostril.
Are Vaccines Safe?
Although vaccines are considered very safe, they can still cause reactions in a small number of pets. Most commonly, cats will feel tired, may run a fever for 24 to 48 hours after vaccination, and may not eat. In some cats, a small, non-painful lump may form at the site where the vaccine was injected; usually disappearing 4 weeks later. Rarely, a cat will develop facial swelling or a severe allergic reaction (anaphylaxis), accompanied by vomiting, diarrhea, breathing difficulties and collapse. Intense facial itchiness may also occur. Anaphylactic reactions are rarely fatal if treated immediately and appropriately.
Are there alternatives to Vaccination?
There are no alternatives to vaccination. Despite the occasional risks associated with vaccination, it is universally accepted that vaccination plays an important role in protecting pets. However, some owners may be disinclined to have their pet vaccinated frequently. For some repeat vaccines, blood samples can measure antibody titers. Though these may not always provide solid evidence of immunity, some clinicians use them as an indicator, along with low risk, that vaccines may be administered at a longer than annual revaccination interval. At this time, not all laboratories are standardized to allow accurate interpretation of results, nor can immunity to all diseases be tested this way. Community health does require vaccination as a strategy to control disease outbreak.
Core Vaccines for Dogs
This disease, caused by the morbillivirus (a paramyxovirus), causes respiratory, digestive, and nervous system signs in affected dogs, and can be fatal in about half of unvaccinated dogs. Recovered dogs may have permanent damage to their nervous systems. The chronic form of the disease can lead to hard pad disease, a chronic thickening of foot pads, and encephalitis, an inflammation of the brain. Some dogs that acquire the virus show no signs or very mild signs, but can easily infect other susceptible dogs. Unvaccinated dogs are at a 350 fold increased risk of contracting this highly contagious disease which is spread by discharges from the nose and eyes of infected dogs.
Infectious Canine Hepatitis
This virus is caused by a viral agent, the canine adenovirus CAV-1, and is spread through infected urine. The virus may cause liver failure, eye damage, respiratory problems, and can be fatal. Commonly encountered clinical signs are vomiting, abdominal pain, diarrhea, and occasionally coughing. It is actually CAV-2, a closely related virus that is used in the vaccine because it is less likely to cause side effects and is cross-protective.
The disease is caused by parvovirus of types CPV-2, CPV-2a and CPV-2b. Infection is both serious and widespread in dogs. Signs, which include severe vomiting and diarrhea with blood, result from the virus damaging the gastrointestinal tract. The disease is spread via infected feces. Death in as early as 48 to 72 hours can occur in some dogs, although sudden death can also occur. Parvovirus infection may also cause bone marrow suppression and myocarditis (inflammation of the heart muscle). This virus is very resistant in the environment and is easily carried around on people's shoes and other objects, leading to virus transfer. For this reason, even indoor hi-rise apartment dogs that never go out require protection. Vaccination is the most effective protective strategy for all dogs, young and old.
Canine Parainfluenza Virus
One of the causes of kennel cough, this respiratory disease is caused by a parainfluenza virus. Characteristic features of kennel cough are a hacking cough, discharge from the nose, and occasional fever. While the parainfluenza virus on its own produces mild symptoms, especially a cough, it is frequently present as a co-infection with other kennel cough agents.
All mammals, including humans, are at risk of contracting rabies, which is almost invariably fatal. Rabies is sometimes called the great pretender because signs are so variable in animals. Rabid dogs may display a "dumb" form, characterized by listlessness, weakness, and paralysis, or the "furious" form of rabies characterized by abnormal aggression. Less commonly, dogs may just have signs of drooling with their tongue hanging out. In areas where risk is high, vaccination of dogs and cats is mandatory. Even dogs that do not go outside much should be vaccinated: rabid bats can fly into homes, and rabid wildlife such as skunks and raccoons can enter a fenced yard.
Research shows that animals with rabies can shed the virus (infect people) before the signs are obvious, so avoid close contact with a stray. Instead, contact the appropriate authorities to rescue it for you.