Ask a veterinarian

By Dr. Alice Crook
First published in Chatelaine's September 2002 issue.
© Dr. Alice Crook

Vaccinating your kitten will make a big difference to her health. The shots protect animals against infectious diseases that cause serious illnesses, such as panleukopenia in cats and distemper and parvovirus in dogs. And vaccinating animals against rabies is crucial for you, too, since the disease is deadly for both animals and humans.

Kittens and puppies should be vaccinated at about eight to 10 weeks of age. Your vet will follow up with two more vaccination boosters about four and eight weeks later and again when your cat is one and two years old. Generally, adult animals are vaccinated once a year.

How they work
A vaccine is a small dose of a modified virus or bacteria. It stimulates the immune system to produce antibodies, which fight off a disease when your animal comes into contact with it. When animals are first vaccinated, they receive several injections to boost the immune response. Over time the animal's immunity wanes, until she receives another booster shot.

There's some debate about the necessity of annual vaccinations. We now know that some vaccines protect animals for more than a year and there's some risk, however mild, to your pet every time she's vaccinated (see " The risks " below). The Canadian Veterinary Medical Association (CVMA) recently reported that less frequent vaccination will probably be the trend in the future, but currently there isn't enough information on how long immunity lasts to change the recommendation of yearly vaccinations.

The risks
Animals may suffer adverse reactions to vaccinations but they're usually mild. For example, your cat may be tired, slightly sore or feverish for a day or so afterwards. In rare cases, animals have severe allergic reactions, which can cause weakness, breathing problems or collapse. It's common to feel a small lump for a few days after vaccination, but if it doesn't go away or grows larger, see your vet. Occasionally, cats develop a fast-growing tumour called a sarcoma at the site of a vaccination, which must be removed surgically.

Special circumstances
Indoor pets also need to be vaccinated. Even if your animal doesn't come into contact with other animals, some germs--such as parvovirus in dogs and panleukopenia in cats--are extremely hardy and can be carried into your home on people's shoes or clothes, exposing your pet to infection.

While some vaccinations, such as rabies, are must-haves for your pet, others depend on factors such as where you live. For example, vaccinating your dog against Lyme disease is a good idea if you live in an area where it's a problem, but it's unnecessary otherwise. Your vet is the best person to advise you about what's right for your pet, taking into account where you live and your circumstances. She'll also be aware of any future changes in the CVMA vaccination guidelines.

Dr. Alice Crook co-ordinates the Sir James Dunn Animal Welfare Centre at the Atlantic Veterinary College, University of Prince Edward Island. She also chairs the Animal Welfare Committee of the Canadian Veterinary Medical Association.