Vaccine dangers

by Hsin-Yi Cohen

Read the in-depth article in November's Dogs Today about the Leptospirosis vaccine and alleged outbreaks. Here is some extra background information about vaccine reactions and over-vaccination. Dogs Today is currently looking at parvovirus and is hearing reporting of outbreaks and a 'new strain' that appears to killed some vaccinated dogs. If you have any knowledge of such cases please email

Vaccines have long been regarded as one of the greatest developments in human and veterinary medicine, with their ability to reduce illness hardly questioned. However, while a complete set of puppy vaccinations and annual boosters is still the norm (and what is currently recommended by the British Small Animal Veterinary Association), more and more dog owners, breeders and even vets are starting to question the risks associated with over-vaccinating and the stress it puts on the dog's immune system - leading, many believe, to a range of autoimmune diseases, allergies, organ failure, brain and nerve damage, cancer and possibly even death. While research conducted to explore the risks of vaccines has so far not gathered enough information to give a definitive answer on the safety of vaccines, many studies do seem to show a strong association between vaccination and adverse side effects; in particular, a report in the Journal of Veterinary Internal Medicine (1996) providing clinical evidence that vaccines can trigger immune-mediated haemolytic anaemia in dogs, a terrible disease that can kill in a matter of days, and another study in the Journal of Veterinary Medicine (2003) confirming that both dogs and cats can develop vaccine-induced cancers at their injection sites.

Catherine O'Driscoll believes that these findings are just the tip of the iceberg. Devastated after losing three young dogs to what she believed was adverse vaccine reactions and watching her other dogs suffer similar debilitating illnesses, Catherine was determined to protect other owners from her tragedy and so set up Canine Health Concern, dedicated to sharing information about canine healthcare and educating owners about the unnecessary risks they may be taking with their pets' lives. Since launching CHC and spreading the word, Catherine has been receiving three or four emails every week, telling heart-breaking stories of pets tragically lost to mysterious illnesses following vaccination.

One reads: "I wish to God I [had] found your site before my two beautiful dogs were vaccinated in April. Unfortunately, I didn't know anything about the harmful effects of vaccine on our beloved friends. Tragically, my nine-year-old Golden, Tyson, passed away from liver and spleen complications. My vet said it was an autoimmune reaction to his vaccines. I feel like my heart is completely broken, empty and hollow. In addition, I feel so angry at the vaccination company and at my vet for not telling me this was a possible reaction to vaccination. Two agonizing weeks of pain and desperation and almost $1,000 later, my poor baby boy, Tyson, is gone. I would have gladly given someone everything I own to save him, but I couldn't help him."

Catherine passionately believes that today's pet dogs are being subjected to unnecessary, excessive and potentially dangerous vaccination as a result of marketing pressure from vaccine manufacturers, coupled with naïve or apathetic compliance on the part of most vets. She is particular sceptical of annual boosters, which seem to put an unnecessarily frequent immune load on the dog's system, especially in light of recent research that suggest that antibodies to viral vaccines last for several years; therefore (as in humans) a vaccine given in puppyhood (or childhood) can provide immunity for several years of life, without the need of annual boosters. In fact, the antibodies already in the body simply fight the booster and so no additional protection is provided. However, Catherine argues, every time your dog is injected with the booster, you are laying him open to the host of adverse side effects, from chronic skin allergies to life-threatening anaphylactic shock.

Catherine is not alone in her view. Many leading veterinarians, both in the UK and the United States, believe that there has been a significant increase in the frequency of blood, autoimmune and allergic diseases in the pet population since the introduction of canine vaccines. Some are worried not only about the effect of the viral and bacterial antigens within the vaccines but also the adjuvants added to vaccines to further stimulate the immune system, such as toxic aluminium and mercury.

In the face of the lack of information about vaccine reactions, Catherine embarked on her own research to find out more. With the help of vets, Catherine devised a vaccine survey that scanned 3,800 dogs based on the voluntary return of a questionnaire by owners. The survey found a definite statistical correlation between a vaccine event and the onset of a number of specific illnesses - in fact, it was conservatively estimated that 1 in 10 dogs suffered illness within three months of vaccination. It also seemed to suggest that a large percentage of dogs contracted the very disease that they had been vaccinated for, showing that the vaccines were no guarantee of protection.

Catherine's observations have been echoed in the United States where mounting evidence about the risk of vaccines has led the authorities to reconsider the need for traditional annual boosters, and in September 2001, the American Veterinary Medical Association approved a new 'Principles of Vaccination', stating that "unnecessary stimulation of the immune system does not result in enhanced disease resistance and may increase the risk of adverse post-vaccination events."

Dr Ronald Schultz, Chairman of Pathobiological Sciences at the University of Wisconsin School of Veterinary Medicine, is at the forefront of vaccine research and one of the world's leading authorities on veterinary vaccines. The results from his challenge studies (where laboratory animals are deliberately subjected to the disease threat) show that live virus vaccines are protective for at least seven years, if not for the lifetime of the animal (eg, once fully immunised, more than 90 per cent of dogs retain immunity to parvovirus-2 for more than seven years and distemper immunisation may last up to 15 years) and this has led the American Animal Hospital Association (AAHA), The American Veterinary Medical Association, the American Feline Academy and the Canadian Veterinary Medical Association to revise their guidelines to vets.

Accordingly, it is now recommended that the interval for major viral diseases of normal adult dogs can be safely extended to three years. Furthermore, vaccinations are divided into 'core' or 'non-core', with the latter being optional and administered selectively based on the animal's geographic and lifestyle exposure and an assessment of risk/benefit ratios. Thus, parvovirus would be a core vaccine while Leptospirosis would be a low-priority, non-core vaccine. The guidelines also stress the importance of informed consent from owners and encourage vets to discuss clearly risks and benefits with clients, as well as documenting and reporting all adverse reactions.

Should we in the UK be pushing for a similar change in vaccine protocol so that dogs are vaccinated at longer intervals and vaccines are re-categorised into essential or optional? This is certainly the view of a group of vets - Dogs Today's own Richard Allport and Nick Thompson included - who signed a letter to the Veterinary Times in January 2004, citing the dangers from vaccines and asking for a change in vaccine protocol. Unfortunately, in contrast to the pro-active approach taken in the United States, Britain seems to be retaining a conservative stance. The British Small Animal Veterinary Association (BSAVA) stated in its vaccine policy:

"In recent years there has been much discussion and concern both within and outside the veterinary profession regarding current protocols for the vaccination of companion animals (dog and cat). The major concern has been the spectrum of adverse reactions that have been associated with the administration of vaccines and, related to this, the issue of frequency of administration of vaccine boosters. The single most significant contribution has been the report of the UK Veterinary Products Committee (VPC)... This report again emphasises the safety and value of vaccination, and presents UK data on the very low prevalence of adverse reactions to these products in dogs and cats. On the issue of extended booster intervals, the VPC recommends that, until such time as more extensive scientific evidence is presented, there is insufficient basis to alter the current data sheet recommendations for companion animal vaccines."

The BSAVA is basing this policy on an epidemiological study - done partly in response to Catherine's CHC survey - conducted by the Animal Health Trust, a registered charity dedicated to improving the health and welfare of the UK's dogs and cats. Using a number of British veterinary practices that had agreed to participate and questionnaires sent to owners about specific dogs randomly selected from the practice databases, the AHT asked questions about a range of dog health issues, in order to prevent the study hypothesis from being known to the respondent. The results from 4,040 dogs show that there is no evidence of a temporal association between recent vaccination and signs of ill-health, although the paper did admit that "the absence of a statistically significant association did not necessarily imply that recent vaccination had no effect on canine ill-health."

The results of this study have been widely cited by the vaccine manufacturers and vets as independent support, which shows the need to continue with the current yearly vaccination regime. However, Catherine has reservations. In her latest book, Shock to the System, she points out that the AHT study was funded by the National Office of Animal Health (NOAH), a trade association that represents the manufacturers of veterinary vaccines and other drugs in the UK. Furthermore, she notes that the VPC committee that advises the BSAVA regarding canine and feline vaccines is made up of four members only, two of which are consultants to a vaccine manufacturer and one who is a member of the Veterinary Defence Society Limited. How - she asks - can such a committee and study be unbiased and "independent"?

Dr Jean Dodd, a leading US expert on canine vaccines, shares Catherine's reservations. "Studies not designed by epidemiologists unassociated with the industry are likely to be of flawed design."

Perhaps, as a compromise, we should be pushing for informed consent, a concept that does not seem to be widely put into practice with regards to vaccines at the moment. While the BSAVA vaccine policy does say that "owners might request veterinary surgeons to use revaccination intervals different from those recommended by the manufacturer following an informed discussion of the relative risks and benefits", most pet owners are simply told to vaccinate and when to return for annual boosters. Very few have had the risks and benefits explained to them, so that they can make a decision for themselves. This is in stark contrast to other life-threatening procedures a vet might perform (eg surgery) where options and outcomes are clearly discussed before any action is taken.

The one thing everyone agrees on is that we need more information. The vaccine industry concedes that adverse reactions do occur but insists that they are so rare, that their significance is negligible. But just how rare are they? Without a truly independent study - not funded or designed by the vaccine industry - following a large group of dogs over a significant period of time (and compared against a good control group) - it is impossible to tell. We also need a better reporting system for vaccine reactions and more willingness or ability on the part of vets to report any events. We need better understanding of the way vaccines affect dogs' bodies and more information about the prevalence of key diseases. We also need reliable information on the effectiveness of vaccines, from their level of cover to the length of immunity. Unless these questions are answered, the debate will rage on.

Article copyright of Hsin-Yi Cohen and Dogs Today