The Risks and Benefits of Vaccinating Pets

By Beth Boynton, D.V.M.

Most of us have heard that a year in the life of a dog or a cat is the equivalent of seven years in a human lifespan. That means it is vital that pets receive at least an annual medical checkup by a licensed veterinarian. These examinations can lead to early disease detection. Equally important, they often involve vaccinations to protect companion animals against diseases.

Vaccines have reduced the incidence of many major diseases for humans and for animals. Rabies, canine distemper, adenovirus, parainfluenza virus, and canine parvovirus are the core diseases against which dogs are inoculated. In cats, the traditional vaccines given are for panleukopenia, rhinotracheitis, and calici virus. Other vaccines that may be recommended based on risk factors include: bordetella, corona virus, Lyme disease, leptospirosis, and giardia in dogs; and chlamydia, leukemia, feline infectious peritonitis, feline immunodeficiency virus, bordetella, giardia, and dermatophytosis in cats.

Basic vaccination protocols vary by clinic. Disease incidence can vary with geography and year. In general, we have greatly reduced the incidence of many serious and fatal diseases, but we know the viruses are still seen in populations of domestic and wild animals. Direct contact is not necessary to spread diseases just contact with body secretions. Vaccines generally are very safe but as with human vaccines, animal vaccines in rare occasions may be associated with side effects sometimes serious.

In the early 1990s, researchers began noticing that vaccines with additives to improve immune response seemed to be linked with tumors in cats. Roughly two of every 10,000 cats, it was discovered, will form an inflammation that becomes a sarcoma, or tumor. This prompted veterinarians to ask, how often do we really need to vaccinate cats? What's the length of immunity? What vaccines are appropriate for indoor cats versus outdoor cats?

The vaccine industry responded by developing less reactive additives, manufacturing effective products without them, and promoting vaccines given in alternate ways.

In the 1998, the American Association of Feline Practitioners (AAFP) helped veterinary practitioners formulate new vaccination protocols for cats. These recommendations included a core vaccination series for kittens, beginning at six to eight weeks and with boosters every three to four weeks until the kitten is about sixteen weeks. (Puppies need an equivalent series.) Optional vaccines may be indicated if the cat will be outdoors or exposed to many cats. A year later, core vaccines such as rabies and upper respiratory should be administered, along with any indicated non-core vaccines. In 1998 the AAFP also recommended that adult cats have upper respiratory boosters every three years instead of the traditional annual immunization. Rabies vaccine may still need to be given annually recombinant vaccines do not have the proof for longer duration of immunity yet.

The American Animal Hospital Association has just published new guidelines for canine vaccinations, also suggesting longer intervals between vaccinations for some products in older dogs. Products vary greatly, and some products that might be chosen for safety features for example, may only give a year of expected immunity. Several of the non-core vaccines such as bordetella, leptospirosis, and Lyme disease vaccine do not confer long immunity and need to be given at least yearly. Ask your veterinarian about the efficacy and duration of recommended vaccines. This area continues to be studied and remains controversial. 

Unfortunately, many pets remain unvaccinated. But compliance with vaccination protocols helps reduce disease outbreaks and their effects in the broader animal population. Vaccinations are an essential part of good health care. At your pet's annual exam, confer with your veterinarian, look at your pet's health and lifestyle, and formulate a vaccine plan appropriate for those factors.

Beth Boynton, D.V.M., is a community practice veterinarian with University of Minnesota's Veterinary Teaching Hospital.This column is an educational service of the University of Minnesota. Advice presented should not take the place of an examination by a health-care professional. For more health-related information, go to http://www.healthtalk.umn.edu/