Are Veterinarians Over-vaccinating?

Are veterinarians really over vaccinating? Recently, claims of a class action lawsuit surfaced accusing veterinarians of vaccinating pets that don't need it.

The Law Firm of Childress Duffy Goldblatt, Ltd. of Chicago, Illinois, is investigating the pursuit of a class action lawsuit arising from the misrepresentation of the need for pet vaccinations. The investigation claims that every year over 30 thousand dogs and cats in the U.S. die from adverse reactions from unnecessary vaccines.

Are vaccines needed?

Over 10 years ago, some research was conducted that questioned the immunity resulting from vaccines and whether annual vaccinations should be required. There have not been any conclusions in this research. However, during this time, most veterinary schools in the U. S. have recommended a reduction in the number and frequency of required vaccination.

Some veterinarians believe that annual revaccination is an important and critical part of preventative health care. Others suggest that there is little scientific information to suggest that annual revaccination of older dogs is necessary for some diseases. There is insufficient information regarding the duration of immunity beyond a year. Of course, some vaccines (rabies) are required by law.

Vaccine "titers," a blood test that determine the presence of antibodies that develop in response to the vaccine, can be done to help determine if a pet really needs a vaccine prior to actually getting a vaccine. The problems associated with "titers" is that very few laboratories perform the test and titers are often more expensive than the vaccines.

According to several veterinarians interviewed, the biggest obstacle to vaccine titers is that pet owners don't want to pay $100.00 to $200.00 for titer testing to determine if a vaccine is required when they can get the vaccine for a fraction of that cost.

Until recent years, annual vaccines were recommended in both dogs and cats. However, in 1998, the American Association of Feline Practitioners published a report recommending vaccinating adult cats against panleukopenia virus, feline herpesvirus-1, and feline calicivirus, every three years, rather than annually.

In the spring of 2003, the American Animal Hospital Association Canine Vaccine Task Force released its vaccination guidelines that recommended three-year booster intervals in adult dogs for distemper virus, parvovirus, adenovirus-2, and parainfluenza virus.

The above recommendations may change as more information is being made available in a regular basis. The important factor is that the benefits must outweigh the risks. For example, if you have an outdoor cat the benefit of an annual vaccine to prevent some very deadly contagious diseases common in outdoor cats probably outweighs the risks of the vaccine in the eyes of most veterinarians.

Do vaccines actually cause harm?

Vaccines have been associated with minor allergic reactions such as facial swelling and itching to severe reactions associated with the formation cancerous tumor in cats. Vaccines have also been linked to autoimmune diseases in dogs such as anemia, platelet problems,and joint disease.

The number of pets that experience a reaction is very low, although it is difficult to find accurate data as many reactions are not reported or either falsely-associated, or not-associated with the vaccine.
Unfortunately, there is also no longer a national database in the United States that allows veterinarians to report adverse vaccines reactions or to obtain information about adverse reactions to particular products. The U.S. Pharmacopeia's Veterinary Practitioners' Reporting Program lost funding and was discontinued in April 2003.

According to information published in the website, some vaccine reactions may be as frequent at 1:1,000 to 1:10,000.


Vaccinations have saved the lives of millions of dogs and cats. Before the days of effective vaccines, dogs routinely died from distemper, hepatitis, leptospirosis, parvovirus and complications of upper respiratory infections. Current vaccination programs protect our dogs, cats, and us from the threat of rabies.

Despite the well-known benefits of vaccination, the practice of annual vaccination of mature dogs and cats is a matter of debate. One fact is clear, pets should not be over-vaccinated. Vaccines can be associated with some significant problems and the benefit of the vaccine must outweigh the risk of the vaccine. To determine what vaccines your pet needs, your veterinarian should weight the risk-benefit relationship that is relevant to your pet and based on the most current research and recommendations available.

Until more research is done and better data is collected to definitively determine the needed frequency of vaccinations, choose a veterinarian you trust and ask them what they believe is best for your pet. Regardless, your pet should receive an annual examination by your veterinarian.

Additional Comments:

Letter to the Editor: Comments from a Vet about Over-vaccinating