Our Unique 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 “adverse events” 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

By carefully evaluating each dog’s 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.

We recommend vaccinating puppies for parvovirus and distemper (“DP,” a 2-in-1 vaccine) and rabies, making sure that puppies are vaccinated every 3 to 4 weeks, with the last DP vaccine given at 16 weeks of age or older. For kittens, we recommend vaccinating against Feline Distemper, Herpesvirus, and Calicivirus (“FVRCP,” a 3-in-1 vaccine given every 3 to 4 weeks, with the last one given at 16 weeks of age or older) 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!

Pet Vaccinations in WilmingtonWhat We Do

At the first annual exam for adult pets, all dogs are evaluated for risk and any required vaccines. 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 very low..

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 feline 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 feline 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. These laws are constantly being updated according to CDC recommendations but vary from state to state. At present, Delaware has some of the strictest rabies laws.

According to the vaccine label, the vaccine is licensed for healthy animals. Medical exemptions can be given for up to one year for pets residing in Pennsylvania; Delaware has no official exemptions. This means that unvaccinated cats and dogs are subject to quarantines of up to 6 months and owners subject to fines if their unvaccinated animals bite or scratch humans or receive bite wounds from other animals, known or unknown, vaccinated or not vaccinated.

With the health of your cat or dog in mind, we will discuss your pet’s risks of exposure versus risks of adverse events if vaccinated, with state laws and their consequences/penalties in mind, and allow you to make the decision for your pet.

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 3-in-1 vaccine was not ruled out. Restricted use of the vaccine can only have positive benefits in this regard.

We see very few vaccination reactions in kittens. We attribute this to our policy of giving only one injection every 3-4 weeks and separating out the rabies vaccine for a different office visit.

Lyme Disease Vaccine

Expert consensus on whether or not to give the Lyme vaccine in areas in which Lyme exposure is prevalent is lacking. 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, typically respond promptly and well to 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 (polyarthropathy) as well as kidney disease. This is probably due to an immune-mediated condition because of increased genetic risk. Experts differ as to whether or not vaccinating dogs may predispose them to the Lyme polyarthropathy 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. Similar clinical results were obtained in dogs seen at the University of Pennsylvania veterinary school after giving them the original bacterin vaccine before they were naturally infected (Dr. Meryl Littman).

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 only about 70% of dogs (Dr. Ron 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) within the dog. For this reason, diligent topical or oral 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 (Dr. Rich Ford). Others disagree, arguing that the side effects of the vaccine and it’s relatively poor efficacy outweigh the risks of exposure and disease (Dr. Jean Dodds).

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 currently do not offer this vaccine based on our assessment of the risks versus benefits including prevalence of symptomatic dogs, response to therapy in symptomatic dogs, and severity of vaccine reactions. However, all the experts agree that excellent tick control is the best course of action. Note that ticks can carry other serious diseases like Rocky Mountain Spotted Fever, Babesiosis, Ehrlichiosis, and Anaplasmosis. Year-round tick control with oral or topical products is recommended in Delaware and Pennsylvania, as ticks can be active all year-round.

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.
  7. Dr. Jean Dodds, personal communication, November 2016.

vacs3Leptospirosis Vaccine

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 certain serovars 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 or immature immune systems.

If you do get the vaccine (we do not offer it at WAH but can special order it in special circumstances), 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,  as suggested by the 2011 American Animal Hospital Association’s Canine Vaccination Guidelines, 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.)

Canine Influenza Vaccines

The first Canine Influenza Virus (CIV) vaccine to be manufactured was first approved in 2009, for the H3N8 strain that has been recognized since 2004. A newer vaccine to the H3N2 strain was released with a conditional license in 2015.

Canine flu H3N8 strain appears in most dogs like regular kennel cough. Twenty percent of dogs can be infected with no clinical signs. Dogs showing signs can be as high as 60-80% of those exposed.  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.

According to Cornell’s Animal Health Diagnostic Center (AHDC):

CIV is transmitted by close contact with an infected dog, often in a restricted space such as an animal shelter, day care center, or boarding kennel. Casual contact is less likely to be a factor mainly due to the relatively low amount of virus shed by an infected dog. Virtually all dogs are susceptible regardless of age or breed.

Influenza virus infection in dogs follows a similar pattern to infections in other species. The onset of clinical signs will be 2-3 days post infection. Peak of virus shed is 3-4 days post infection and the presence of infectious virus declines rapidly with the onset of an immune response. Dogs coughing for > 10 days are not infectious as the cough is due to damage to the respiratory tract epithelium. While in the past CIV infections in and of themselves have not shown a significant mortality rate, CIV infections as well as other respiratory viruses compromise the normal defenses of the lung permitting secondary bacterial pneumonias.

(https://ahdc.vet.cornell.edu/news/civchicago.cfm. Last visited November 25, 2016.)

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.

In one study of 700 dogs, the H3N8 vaccine was reaction-free, most likely meaning without immediate reactions like fevers and injection site pain. As with 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 canine rabies vaccines).

Currently we are suggesting that clients consider the H3N8 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.

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.

The H3N2 strain appears to have burned out, as shown by data from the AHDC Canine Influenza Virus Surveillance Network.

Feline Leukemia Virus (FeLV)

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. We do not carry this vaccine.

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.