Vaccines

Our Progressive Vaccination Protocol

Vaccinations To begin, Wilmington Animal Hospital takes a progressive approach to vaccines, designed to minimize the risk of negative reactions in young and healthy pets as well as to ensure the safety of sick or older pets. As a result of our rather unique and highly individualized vaccine protocol, we are the first choice for pet owners who have at-risk animals, animals that have experienced a negative reaction to a vaccine, or who are holistically-oriented when it comes to the treatment of their pet.

Our Philosophy

Since 1996, Wilmington Animal Hospital has adopted a very conservative vaccination policy. Our goal is to minimize the number of vaccines given to any one patient. We have found that this has resulted in a reduction of problems in our patients. For example, vaccine reactions in our patients are very rare. In short, we believe that vaccines can prevent diseases, but they never make you healthy.

How We Do It

We have found that by carefully evaluating each dog and cat's risk of exposure to infectious diseases, we can safely limit the number of vaccines that each patient requires.

Wilmington Animal Hospital has also undertaken a very critical review of all of the vaccinations available for our patients. Working with experts at the veterinary schools of Cornell University and the University of Wisconsin, we have determined the vaccines that are safe and most effective as well as those that are not necessary and/or that pose a higher risk of reaction than the actual risk of the disease.

Most of our puppies receive 3-5 vaccinations (for parvovirus, distemper virus, and rabies) and most of our kittens receive 4-7 vaccinations (combination vaccination for feline distemper, herpes virus, and calicivirus given once or twice depending on risk; and rabies). Contrast this to the more common vaccination schedules in which puppies receive anywhere from 24 to over 50 vaccine agents by 5 months of age, and kittens receive anywhere from 7 to over 14 vaccine agents!

What We Do

At the first annual exam, all dogs are evaluated for risk and vaccine requirements. For example, dogs boarding at certain kennels may be subject to certain vaccination requirements. Whenever possible, we begin measuring immunity to parvovirus and distemper in our patients. These tests that measure immunity are called titers.

At each annual exam, we reevaluate and do the titer tests according to the dog's risks and requirements. Most of our patients that do not board or who board at Wilmington Animal Hospital are able to stop all vaccines (except rabies) and titers by the age of 10, when the risk of contracting infectious diseases is virtually zero.

Similarly, for cats we evaluate their risks and vaccine requirements. Cornell University's Feline Health Center has performed studies evaluating duration of immunity in the feline distemper/herpes virus/calicivirus vaccine. The American Association of Feline Practitioners and the American Animal Hospital Association has been very proactive in developing vaccine recommendations for cats. Consequently, there are a number of boarding kennels and veterinary facilities that no longer require annual feline booster vaccinations.

For our patients that have no risk of exposure to infectious diseases, booster vaccinations are usually not recommended (except rabies, according to state law). These cats include solo indoor cats that never board or never go to grooming facilities.

For our patients who have a risk of exposure to infectious diseases, booster vaccinations every 3-5 years are recommended for the distemper/herpes virus/calicivirus vaccine. This includes cats that go outside; cats living in households that will be bringing in new, stray, or rescue cats; and cats that board or go to grooming facilities. Occasionally, we will run titers on these cats if we have concerns for risks posed by vaccination.

The Exception: Rabies

Rabies vaccination is recommended in compliance with state laws.

According to the vaccine label, the vaccine is licensed to be administered to only healthy animals. Medical exemptions can be given when the patient is not healthy enough to receive the vaccination.

However, in the event of a human exposure, state public health laws override individual medical exemptions. For example, if a cat has been given a medical exemption, but goes outside and receives a bite wound of unknown origin, this cat will still be required to undergo a six-month quarantine or be euthanized. If an unvaccinated dog or cat bites a human, including a member of a veterinary staff, this pet will be required to undergo a 10-day quarantine at the owner's expense, even if the pet had not been healthy enough to be vaccinated.

What We Have Found

Wilmington Animal Hospital feels that our patients are healthier with the judicious use of vaccines. For example, a study published in the American Journal of Veterinary Research in 2005 showed that cats inoculated with the feline distemper/rhinotracheitis/calicivirus vaccine developed antibodies to feline kidney tissue. Although none of the eight cats in the study developed kidney disease during the 56 weeks of the study, a direct connection between kidney disease in cats and the three-in-one vaccine was not ruled out. Restricted use of the vaccine can only have positive benefits in this regard. (For more go here.)

We see very few vaccination reactions in kittens. We attribute this to our policy of giving only one injection every 3-4 weeks at most to kittens.

The Lyme vaccine is controversial. In the U.S., two basic forms of the vaccine are on the market. One type is made from the whole bacteria (bacterin) and the other, a recombinant vaccine, is made from the only protein (rOspA) needed for protection from the bacteria. Bacterins in general tend to cause more reactions. Subunit vaccines like the rOspA one are considered to be safer as they only introduce one antigen (foreign protein) into the body.

In some areas where Lyme disease is prevalent, over 70-90 percent of dogs (healthy as well as sick) will test positive. More than 95 percent of these dogs that are exposed to the Lyme organism are not genetically predisposed to develop serious illness. Some of these dogs may develop non-serious symptoms that resolve within a week on their own. Those dogs that do develop Lyme arthritis, less than 5 percent of those that are exposed, are easily treated with safe and inexpensive antibiotics.

A less common, but more serious form of Lyme disease that tends to affect Labrador Retrievers, Golden Retrievers, and Shelties can include the joint form (arthropathy) as well as eventual kidney disease. This is probably due to an immune-mediated condition because of genetic risk. Experts differ as to whether or not vaccinating dogs may predispose them to the Lyme arthropathy and/or nephropathy. Studies in mice have shown that first vaccinating them against Lyme disease, and then infecting them with the organism results in severe immune-mediated arthritis and kidney disease.

Finally, the efficacy of the vaccine has been called into question. Response to the vaccine can be measured in two ways. First, seroconversion (the ability to make the intended antibodies) can be measured. In one study, 90 percent of the dogs made the antibodies to the bacterin, and 60 percent to the rOspA vaccine. The other measurement of response is to see how many vaccinated dogs later become ill with Lyme disease. In another study, 78 percent of dogs vaccinated with the bacterin were protected, and out of those, 58 percent were seropositive, 86 percent were seronegative. In both of these studies, however, dogs had not been evaluated for exposure to the Lyme organism before vaccination, complicating the interpretation of the data presented. One expert estimates that all the vaccines for Lyme protect about 70% of dogs. (Schultz) In any case, the vaccines did not appear to confer protection to 100 percent of the dogs vaccinated in real-life situations.

A recent hypothesis (not proven) is that clinical illness with Lyme disease may be related to the number of spirochetes (Lyme organisms) in the dog. For this reason, diligent topical tick prevention may be a good idea. Some experts advocate vaccination to take down the number of spirochetes in the system in order to decrease the likelihood of clinical illness. (Ford)

In conclusion, in spite of more evidence accumulating on Lyme disease and the vaccines for it, the experts continue to disagree on the recommendations for vaccinating for Lyme disease. At WAH, we do not offer this vaccine and continue to see very few cases of Lyme disease.

Lyme vaccine references:

1. Meryl P. Littman, lecture at Penn Annual Conference 2006
2. Meryl P. Littman, "The Lyme Test is Positive: Now What?" lecture at ACVIM 2007
3. Littman MP et al. ACVIM Small Animal Consensus Statement on Lyme Disease In Dogs: Diagnosis, Treatment, and Prevention. J Vet Intern Med 2006;20:422-434.
4. Dambach DM et al. Morphologic, immunohistochemical, and ultrastructural characterization of a distinctive renal lesion in dogs putatively associated with Borrelia burgdorferi infection: 49 cases (1987-1992). Vet Pathol 1997;34:85-96.
5. Rich Ford, "2012 Vaccines and Vaccination: The Facts v. The Fiction" lecture at PVMA 2012.
6. Dr. Ron Schultz, personal communication, August 2012.

Leptospirosis is a disease that can infect dogs and humans. The bacteria causes severe kidney and/or liver disease.

It is unknown at this time if the actual incidence of leptospirosis is growing in dogs. George E. Moore, DVM, Ph.D., Dipl. ACVIM, of Purdue University, stated in an article in Veterinary Practice News Magazine (October 2010) that, "There's good evidence to support an increase of diagnosed cases of leptospirosis in the U.S." Dr. Ron Schultz of the University of Wisconsin states that there has been no increase in the number of human cases during the past 10-20 years; and a recent study looking for serologic prevalence in raccoons in Wisconsin found 25 percent prevalence, which was the same as found in a study 25 years ago. (Personal communication November 2010). Experts all seem to agree that the incidence of the disease is increasing in urban dogs, as wildlife concentrations increase in these areas. An urban dog is now just as likely to become infected as a hunting dog.

Until recently, Leptospirosis has been considered a zoonotic disease, meaning an infected dog can pass it on to a human. While this potential for transmission exists, it is being called into question. The belief now is that humans contract leptospirosis through the same sources as their dogs, not from their dogs. People like triathletes who swim in open water are at risk.

Before you rush out to get your dog vaccinated, here are five important issues related to this vaccine.

  1. Ten serovars (types) of Leptospirosis are most likely to infect dogs. A vaccine that only protects against two serovars-or even 4 serovars- might be missing the one that could infect your dog.
  2. Infection is much more common than disease.
  3. Duration of immunity, or how long the vaccine lasts, is a concern. For most of the Leptospirosis vaccines, duration of immunity varies from 3-18 months, and varies with different serovars, some creating longer-lasting immunity than others. The immunity to three of the four common serovars most likely lasts 12-18 months. (Schultz, Ford)
  4. Leptospirosis is significant because it is a disease that can be transmitted to humans. Ideally, the vaccine should prevent the dog from getting infected by the leptospirosis organism. However, studies have shown that dogs vaccinated with certain vaccines and then exposed to leptospirosis, while not necessarily getting sick themselves, still "shed" the organism from one serovar in their urine. This could pose a false sense of security to dog owners and actually increase their risk of contracting the disease. Two of the veterinary vaccines now prevent infection and shedding of the organism.
  5. The safety of the vaccine has come into question. All of the vaccines have been shown to cause a hypersensitivity reaction in genetically predisposed animals, and this can last up to four years. (Personal communication with Dr. Ronald Schultz, School of Veterinary Medicine University of Wisconsin-Madison, October 2005, November 2007, August 2012)

In our experience, this disease is extremely rare in our patients, and seems to be found mostly in dogs with poor immune systems.

If you do get the vaccine (we do not offer it at WAH), consider the following:

  • Do not get it at the same time as any other vaccines, especially viral ones, as they drive the immune responses differently. The body preferentially creates immunity to the Leptospirosis over the viral components (like Distemper and Parvovirus).
  • Do not give to dogs less than 12 weeks of age. In fact, if you can wait until after the initial core vaccines have been given, this may be safer for your dog.
  • Remember that the more vaccines given in one office visit, the higher the risk of a reaction, especially in dogs less than 22lbs. ("Adverse events diagnosed within three days of vaccine administration in dogs," JAVMA, Oct. 1, 2005.)

The Canine Influenza vaccine is a relatively new vaccine (approved in 2009) for a disease that has been recognized since 2004. Canine flu appears in most dogs like regular kennel cough. Twenty percent of dogs can be infected with no clinical signs. Five percent mortality has been documented. Deaths are from severe bacterial pneumonia and can occur in previously healthy young dogs. Pneumonia usually shows up 10-12 days after exposure.

It appears that infection after casual contact with an infected dog is not a major concern, as the virus is not shed at high levels and is not readily transmitted. Three to four days of continuous contact (like that seen in boarding kennels, for example) is needed for an infected dog to transmit the virus to a susceptible dog. It also appears that coinfection with other respiratory disease agents may be needed for dogs to show signs of the flu. Dogs that play in dog parks or participate in outdoor activities are unlikely to contract the flu virus in these environments.

After exposure to the virus, dogs start shedding the virus in secretions within 24 hours. They stop shedding the virus by 7 days after exposure. Clinical signs usually start by day 2-5 after exposure. Coughing, when present, can last for 30 days.

In one study of 700 dogs, the vaccine was reaction-free, most likely meaning without immediate reactions like fevers and injection site pain. The vaccine has not been in widespread use as of yet to determine further side effects; and of course, like most vaccines, it is difficult to connect chronic problems with any one vaccine that has been given. This is a killed vaccine with an adjuvant (like the rabies vaccines).

Currently we are suggesting that clients consider this vaccine only if their dogs will be at high risk for Canine Influenza (H3N8). Outbreaks have been noted in Delaware, and are mostly from boarding facilities and shelters. Accordingly, if your dog will be boarding, showing, doing obedience trials, or being placed in other situations of prolonged contact with many dogs at once, you might want to consider this vaccine.

Two doses given three weeks apart are required for the vaccine, and immunity does not occur until two weeks after the second dose.

This vaccine, while effective at inducing immunity, does NOT prevent infection. In other words, dogs can still contract the virus and spread it to other dogs, although the amount of virus that is shed is reduced. Like the human flu vaccines, it may reduce the severity of an infection.

Based on the more recent findings that co-infection with Bordetella (commonly called 'Kennel Cough') and Parainfluenza (commonly included in many canine vaccines) may contribute to flu symptoms, vaccination with these (the simple intranasal vaccine) may help prevent clinical flu disease. Other viruses and bacteria can be responsible for these co-infections, but vaccines are not on the market for these agents.

The Feline Leukemia Virus (FeLV) vaccine remains controversial because of a serious risk posed by the killed type of vaccine and because of the lack of risk posed by the virus to adult cats. We do not recommend this vaccine for most cats.

First, the killed form of the FeLV vaccine has been linked to tumors (fibrosarcomas) at the vaccine site. Second, the risk of contracting feline leukemia virus declines markedly after 16 weeks of age, and is extremely low, according to one prominent vaccine researcher, by one year of age. In rare cases in our practice, adult cats may become positive for Feline Leukemia, and they may show signs of illness, but their chances of clearing the virus are excellent. In one unpublished study, 300 susceptible cats were injected with a high dose of the virus directly into the abdomen. Only one cat developed a persistent infection (Personal communication with Dr. Ron Schultz, School of Veterinary Medicine University of Wisconsin-Madison, December 2006.) Other studies proving the efficacy of this vaccine relied on suppressing the immune system in order for the cats in the control groups to succumb to the virus.

The risk of contracting the Feline Leukemia Virus increases with concurrent infection with FIV (Feline Immunodeficiency Virus) and with prolonged direct contact with infected cats. For cats that go outside, this would include sharing similar food and water dishes. In other words, adult cats not only need to have marked exposure to the virus, but also need a compromised immune system to develop a persistent infection with the virus. For these and other reasons, we feel that most of our patients would not benefit from this vaccine, and might actually engender a risk from receiving it.

Feline vaccines in general should be given judiciously because of the cats' unique propensity to form sarcomas (tumors) at injection sites. While it appears that killed vaccines may present a higher risk, all types of vaccines and even other drugs injected into cats have been implicated in tumor formation. (JAVMA Sept. 1, 2012).

Additional Resources

Many more vaccines exist and are marketed to veterinarians. We are happy to discuss any vaccines you might be interested in for your pet.

For more information on vaccinations for dogs and cats, visit UC Davis VMTH Canine and Feline Vaccination Guidelines.

For more information on vaccines and potential links to autoimmune diseases, please read the Purdue University and Hayward Foundation Study on Vaccines.