Vaccines, as I have mentioned many times on this blog, are perennially controversial. Many people worry that pets are vaccinated too often. Experts voice concerns that over vaccination may lead to autoimmune disease. Leukemia and rabies vaccines in cats have been linked to cancers at the injection sites.
The obvious goal for every veterinarian and conscientious pet owner should be to vaccinate pets neither too frequently nor too rarely. In an ideal world, we would vaccinate pets exactly as often as necessary. I predict that in the future this will be the norm. But as of 2009, it is impossible to say how often pets need vaccinations.
Some facts are clear. Juveniles (puppies and kittens) need vaccines more often than adults. Animals with different lifestyles need different vaccination protocols. And most important, every individual responds differently to vaccines. Every individual therefore has unique needs.
Measuring those needs is impossible. Blood tests called titers give some idea of a pet’s response to previous vaccinations, but titers measure only half of the picture. Titers measure antibody levels in the blood. However, antibodies cannot function without another component of the immune system called cell-mediated immunity. At this time there is no way to measure cell-mediated immunity. Therefore there is no way to measure a pet’s true level of immunity to disease.
I agree that many pets are vaccinated more often than necessary. On several instances I have treated animals for autoimmune disease and wondered whether vaccines might have contributed to the problem.
However, on hundreds of instances I have treated canine parvovirus. In every single one of these cases I knew with certainty that vaccination would have prevented the problem. I never have treated a properly vaccinated dog for parvo. The vaccine works.
I euthanized a 12-week-old puppy today because of parvo. A vaccine could have saved his life if it had been administered at the right time.
Over vaccination is a bad thing. Veterinarians and pet owners should work to prevent it. But don’t forget that under vaccination is even worse.
Your best option as a pet owner is to find a good vet who will take the time to discuss the controversies surrounding vaccines. Tailor a vaccination protocol to your pet based upon his or her needs, age, and lifestyle.
I have said repeatedly on this blog, and I firmly believe, that children derive emotional and physical health benefits from pets. I believe that pets help children to learn patience and empathy. Studies have shown that children living with cats or dogs may be less likely to develop asthma, and that pet visits motivate hospitalized children to get well. Pets make wonderful friends and confidantes for people of all ages.
However, the intermingling of children and pets poses risks for both. Here are some guidelines for protecting your offspring and your furry pals.
Unhealthy pets can spread disease to people. Children are most at risk. The diseases range from ringworm to roundworm to rabies.
However, the key phrase in the above paragraph is unhealthy pets. The risk to children from healthy pets is very low. The first guideline for safe interactions between pets and children is therefore to confirm that your pet is free of parasites and disease. Your vet can check your pet for disease by performing a physical exam and running basic tests. Broad spectrum anti-parasite medications can be used regularly to protect your children–and your pet.
Pets occasionally bite or scratch children. I have noted that many child injuries occur when an unsupervised, poorly socialized pet interacts with an unsupervised, poorly behaved child. I therefore recommend that you properly supervise and socialize your pet, and that you properly supervise and socialize your child. It’s also a good idea to keep your cat’s nails trimmed.
Injury can be a two way street when pets and children mix. Last weekend at the emergency hospital I treated several pets who wound up hurt (accidentally, of course) when left with a child. One, a Yorkshire Terrier puppy, wiggled out of a five-year-old’s arms and broke her leg. I expect her to make a full recovery. Another, a Terrier cross, was not so lucky. A child was holding her leash and she broke loose near a busy street. I don’t need to tell you what happened next. The child was inconsolable. For the sake of your pet and your child, do not allow your child to handle your pet unsupervised until he or she is able to do it safely.
Countless other pitfalls exist. Large dogs can knock children over accidentally. Pets can steal potentially toxic (to them) foods from the hands of careless children. For the sake of both children and pets, exercise common sense and practice due diligence.
The skunk was captured by San Francisco’s department of Animal Care and Control. It had been behaving erratically, staggering, and acting disoriented. Animal Care and Control did not have a veterinarian on duty at the time (it was the middle of the night), so the officer brought the skunk to the emergency hospital where I was working for euthanasia (the skunk’s condition was deemed to be beyond help).
The skunk’s likely diagnosis was canine distemper virus–the same virus that causes serious disease in dogs, wild canids, marine mammals, and African lions.
For the most part, diseases tend to be species specific. Dogs most often catch diseases from other dogs. Cats catch diseases from other cats. Humans catch diseases from other humans.
But there are exceptions. Rabies is the most famous exception. The virus can infect any mammal. Many parasitic worms can infest multiple species. Feline toxoplasmosis can infect humans, sea otters, and wild cats. Canine distemper virus can infect a variety of wild animals.
Fortunately, basic hygiene and vaccinations can protect your pet from many wildlife-borne diseases.
Pets who have minimal exposure to other members of their species (such as indoor cats and small dogs that rarely go out) may still be at risk for exposure to wildlife. Talk to your vet about these risks, and make life style and vaccination decisions accordingly.
Molly was minding her own business when the raccoon attacked her. The poor dog didn’t see it coming.
The sweet nine-year-old Yorkshire Terrier stepped out of her owner’s back door for her bedtime bathroom break. She rounded the corner. The owner heard a commotion, and the bloodied dog scampered back to the safety of the home. If her tail had been more than a stub, it certainly would have been between her legs. The incident lasted just a few seconds.
When I treated Molly I found several bite wounds on her face and muzzle. She also had three or four puncture wounds on her rear end. From her injuries, it appeared that she had run headlong into the raccoon. The raccoon savaged her face. The dog turned to run away, and was tagged a few times on her rump during the escape.
Fortunately, the injuries were not serious. But legal matters threw an additional wrench into the gears of the evening. After animal attacks I am required to determine the victim’s rabies vaccination status. I wish the owner had lied.
Molly lived the life of a homebody. She lived mostly indoors. The owner had decided to forego rabies vaccination for several years. Her vaccines were overdue.
Molly’s chances of contracting rabies during the encounter were basically nil. But San Mateo County law still dictates that pets with overdue rabies vaccines must be quarantined for six months after wild animal encounters. Five and one half months of the quarantine can take place at home. But the first 14 days must take place at the San Mateo animal shelter.
I’ve never been to that shelter. But I can’t imagine Molly is happy there. I feel bad for her–none of this was her fault.
Hi Dr. Barchas,
I know that the feline rabies vaccine has been associated with fibrosarcomas at the site of injection. Is it possible for the vaccine to cause tumors in other locations? Someone told me that the three-year rabies vaccine was more likely to cause cancer – is this true?
My cats received the three-year vaccine several years ago. One of them developed an aggressive tumor in her abdomen a couple years later. As surgery would not improve her quality of health, we elected to put her to sleep. Although a couple of years have passed, I remain worried about my other cat (her sister) and if my choice to have them vaccinated with the three-year shot contributed to my beloved cat’s death. Thank you for any insight.
Tera
Columbus, OH
You have asked some very good questions. I’ll do my best to answer each of them.
Vaccine-associated fibrosarcomas are cancers that develop rarely at the site of rabies or feline leukemia vaccines. They appear to occur only in cats. The cause of the tumors is very poorly understood.
The cancers develop at the site of injection. I have not seen any reports of vaccines causing tumors in distant locations. Therefore, it is extremely unlikely that your cat’s abdominal tumor was linked to a vaccine. Fibrosarcomas can develop naturally, and if your cat suffered from a fibrosarcoma in her abdomen it likely occurred spontaneously. I sincerely doubt that your decision to vaccinate your cat contributed to her death.
Three-year rabies vaccines usually contain a component called adjuvant that is designed to help stimulate the immune system. One-year vaccines generally do not contain this component. Some people have hypothesized that adjuvant contributes to fibrosaroma development. These people therefore speculate that the one-year vaccine may be less likely to cause cancer than the three-year vaccine. I have not seen conclusive proof of this.
For instance, some studies have suggested that merely inserting a needle into the skin may trigger a cascade of inflammation that ultimately leads to cancer. This implies that the adjuvant is not to blame.
Also, remember that one-year vaccines must be given three times as often as three-year vaccines. The relevant question therefore is whether one-year vaccines are three times less likely to lead to cancer.
A few years ago I attended a lecture by a representative of a company that produces one-year, non-adjuvanted feline rabies vaccines. After the lecture I cornered her (literally–she was trying to get away and I backed her into a corner) and asked the following question. I remember it verbatim.
Can you provide quantitative evidence that three-year vaccines are three times more likely to cause cancer as your one-year, non-adjuvanted vaccine?
Her answer was no. To this day I have not seen any study that proves that three one-year vaccines are safer than one three-year vaccine (if anyone is aware of such a study, please let me know).
It is unlikely that your remaining cat will develop a fibrosarcoma from her rabies vaccine. Fibrosarcomas develop in approximately one out of every 3000 – 10,000 cats that receive the vaccine. I have no reason to believe that your cat is at increased risk.
Although vaccine-associated fibrosarcomas are not common, I still recommend that you never accept a one-size-fits-all vaccination plan for your pet. Good vets always are willing to talk about the risks and benefits of vaccination. Make an informed decision.
Photo: Myriah after removal of a vaccine-associated fibrosarcoma.
Rabies vaccination became a discussion in a dog park . . .
Is the 3yr rabies vaccine exactly the same as a 1yr rabies vaccine and just, on first use, it is only good clinically for 1 yr?
Why, in some states, is the first vaccination a 1yr only vaccination and, in other states, a first vaccination can be a 3yr vaccination if the dog is over one yr old?
Is this just because of individual state laws? This came up around a discussion on puppies and also adoption of dogs and vaccinations.
Fred
Pleasanton, CA
The Vet Blog has not touched upon vaccines in a while. Vaccines seem to be second only to food when it comes to causing controversy on this blog. Now that most of us seem to have recovered from the raw food disucssion, I think it is time to open up a new can of worms.
Tomorrow’s post will discuss the use of titers in lieu of vaccines. Today, let’s talk about rabies vaccines.
Rabies is among the most dreaded human diseases. According to the ultimate repository of human knowledge, Wikipedia, the disease kills 55,000 people each year. Untreated rabies has the distinction of being the most deadly disease known to mankind–mortality is 100%.
Until the advent of rabies vaccines, dogs were by far the leading source of human rabies. In areas where canine rabies vaccination is common, human rabies is very rare. Most human rabies cases occur in developing countries where pets do not routinely receive vaccines. In many of these countries, the mainstay of rabies control is mass slaughter of dogs during outbreaks. Poisoned meatballs were recently used in an attempt to control a rabies outbreak in Bali. In 2006, tens of thousands of dogs in China were killed in an attempt to halt a rabies outbreak.
Pets receive rabies vaccines to prevent the disease from spreading to humans. And given the events in Bali and China it is clear that rabies vaccination, in general, saves the lives of pets–both through prevention of rabies (which is 100% fatal in dogs and cats) and prevention of mass slaughters.
But . . . there is a highly relevant but.
In the United States rabies vaccines are administered by veterinarians to dogs (and sometimes cats) as required by law. Rabies vaccination laws are developed by state or local governments. And once the government gets involved, reason goes out the window.
Some rabies vaccines are labelled only for one year use. These must be given every year. Other rabies vaccines are labelled for three year use.
Those that are labelled for three year use are subject to the laws of local governments. In municipalities where annual rabies vaccination is required, the vaccine is given every year despite the label. In areas where three year vaccination is mandated, the exact same vaccine is given triannually.
There is no rhyme, reason, or hard science to back up any rabies law with which I’m familiar.
Rabies vaccination laws are capricious. This is especially true in cats. A case of rabies in a feral cat several years ago prompted San Mateo county, near San Francisco, to require rabies vaccines in all resident cats. Adjacent San Francisco county does not require feline vaccination. Rabies has not been reported in a cat in either county for several years (more than 100 years in the case of San Francisco).
In many places, rabies vaccinations administered to pets less than 16 weeks old are considered invalid even though there is no scientific basis for such a timeline. A puppy in Alaska recently exposed several people to the disease when it was younger than 16 weeks and had therefore not been vaccinated.
Rabies vaccinations have been linked, rarely, to cancers in cats. Some experts have suggested that rabies vaccination may trigger scary problems such as immune-mediated hemolytic anemia and ischemic dermatopathy in both species.
On balance, there is no doubt in my mind that rabies vaccination benefits pets and people. I’ll take the one-in-100,000 case of ischemic dermatopathy over mass culling with strychnine meatballs (or a high prevalence of human rabies) any day. But I believe that a more rational and scientific approach to rabies vaccination is in order.
The Rabies Challenge Fund is working to investigate the efficacy of rabies vaccines and promote a scientifically validated rabies vaccination schedule for pets. Perhaps some day it, and organizations like it, will lead to rabies vaccine requirements that are evidence based.
But at this point bureaucracy is carrying the day.
Photo: This photo from the CDC illustrates why pets get rabies vaccines.
In 1991 veterinary medicine suffered a disturbing revelation. Two commonly used feline vaccines were linked to the development of malignant tumors at the site of vaccination. The tumors, called fibrosarcomas, are associated with the vaccines for rabies (in cats only) and feline leukemia. They are aggressive and difficult to remove. They occur in approximately one out of every 3000 – 10,000 cats who receives a rabies or leukemia vaccine.
The discovery of these so-called vaccine associated fibrosarcomas lead to the creation of a special task force (called, unsurprisingly, the Vaccine Associated Fibrosarcoma Task Force). The recommendations of the task force were supposed to cause a dramatic shift in the way cats are vaccinated.
Prior to the discovery of the fibrosarcomas and the formation of the task force, most cats were vaccinated against rabies and leukemia every year. The vaccines were administered between the shoulder blades because that is the easiest place to give injections to cats.
The task force recommended that the leukemia vaccine should be administered only to cats who spend time outdoors. The rabies vaccine should be administered as required by law. If possible, both vaccines should be administered no more frequently than once every three years.
Finally, the task force advised veterinarians to change injection sites. Fibrosarcomas between the shoulders are virtually impossible to remove. Therefore, the leukemia vaccine should be administered in the left rear leg, near the ankle. The rabies vaccine should be administered similarly in the right rear leg. If a fibrosarcoma develops in either of these locations, the cat’s life can be saved by amputating the leg–a less than perfect solution to the problem, but better than the alternative.
Vaccine associated fibrosarcomas are a source of angst for me. I have worked during my career to minimize the number of rabies and leukemia vaccines I give to cats. And I always give the vaccines in the rear legs.
However, a very disturbing paper published in the February 1, 2009 Journal of the American Veterinary Medical Association (JAVMA) indicates that many veterinarians are ignoring the recommendations of the task force and needlessly endangering the lives of their feline patients. According to the paper, significant numbers of cats are developing vaccine associated fibrosarcomas between their shoulder blades. This means that significant numbers of veterinarians are still giving rabies and leukemia vaccines in that spot.
Here are the conclusions of the paper.
Conclusions and Clinical Relevance–Despite publication of the vaccination recommendations, a high proportion of tumors still developed in the [region between the shoulder blades] . . . [v]eterinarians are complying with vaccination recommendations to some extent, but need to focus on administering vaccines as [far down] as possible on a limb to allow for compete surgical margins if amputation of a limb is required. (J Am Vet Med Assoc 2009;234:376-380)
What can you do to ensure that your vet is following the task force’s recommendations? Talk to him or her. Ask whether vaccination for leukemia and rabies is appropriate for your cat. If the vaccines are appropriate, ask where they will be administered. Never accept a one-size-fits-all approach to vaccination.
Photo: A vaccine associated fibrosarcoma between the shoulder blades of a cat, courtesy of Texas A&M’s School of Veterinary Medicine.
Green posted a comment on January 7th, 2009 at 9:20 pm
My 7 pound dog is always inside with me or in the fenced urban garden. I take him on leas[h]ed walks at a paved park. When or how could he be exposed to rabies? If our law requires vaccines every three years do you still recommend a yearly vaccine like his vet says. I see a greater, more likely danger in losing my dog to a vaccine reaction than rabies.
I recommend adhering to local rabies vaccination requirements unless a specific reason exists to increase the frequency of vaccination.
Green, your dog is at low risk of exposure to rabies. Remember that low is not the same as zero. For instance, a rabid bat could fly into your back yard and bite your dog. Bats have tiny teeth, and most bitten individuals do not suffer significant wounds. In many instances, the wounds aren’t visible. Bats are ubiquitous in urban and rural areas. They are a leading carrier of rabies in the US.
If a rabid bat in your backyard sounds implausible, consider the case of Zachary Jones, a teenager in Texas who died after a rabid bat flew through his window and bit him while he was sleeping.
Such cases may be rare, but they are sensational and tragic. They give local governments a legitimate reason to take steps they believe may protect humans from exposure to rabies.
Green, if your dog has been vaccinated against rabies at least twice, he’s probably immune for life. Even if he is the one-in-ten-million case in which a mainly indoor dog is bitten by a rabid bat, he probably would be fine.
But there is absolutely no way to prove that. Rabies titers (blood tests to measure immunity) are not 100% accurate. There is absolutely no way to prove that an individual is immune to rabies. I, personally, have been vaccinated against the disease seven times. My titer is very high (that’s good). Yet if I were exposed to a rabid animal I would not sit back with a wait-and-see attitude–after all, only a few individuals in the history of humanity have survived rabies after symptoms developed. I’d high-tail it to the doctor for post-exposure rabies injections.
Rabies vaccinations are required by law not to protect dogs, but to protect people. Whether you agree with the law or not, you only have a few choices. You can obey the law. Or, although I don’t recommend it, you can ignore the law (this may put your dog at risk of euthanasia for rabies testing if he ever bites anyone). Or, finally, you can challenge the law by contacting your local government.
To those who believe that rabies vaccinations are bad for dogs, consider this. Before the advent of canine rabies vaccination laws, dogs were the leading source of human rabies exposure in the US by a mile. Now they are not. The shift has changed the public’s perception of dogs in a very favorable way. That is good for dogs.
Photo: the gentleman depicted died from rabies in 1959, soon after the photo (courtesy of US CDC) was taken.
Vaccines are perennially controversial in veterinary medicine. However, there is one vaccine that causes almost no controversy whatsoever. I am referring to the canine rabies vaccine.
In the United States, local or state governments dictate the frequency of rabies vaccination in dogs. Veterinarians and people with dogs must comply with the laws.
Most municipalities require an initial rabies vaccination after the dog is 16 weeks old. Vaccines given before that date may be considered invalid. The initial vaccine generally is valid for one year. In some places, subsequent vaccines are good for three years. In other places, annual revaccination is mandated.
In rabies-free areas such as the United Kingdom, Hawaii or Australia rabies vaccinations may not be required at all.
Legally mandated rabies vaccination requirements have nothing to do with dogs’ needs. Because rabies can spread to humans, governments generally are concerned only with protecting public health.
And, like most issues involving government oversight, rabies vaccination regulations may be logically spurious. A recent case of rabies in a young puppy (less than 16 weeks old) in Alaska has led some vets to question the rationality of making dogs wait until they are 16 weeks old to be vaccinated. Also, many municipalities will not license a dog whose rabies vaccine was given when it was 15 weeks and six days old. Some veterinarians have been known to get around this problem by changing the dog’s birth date in their records.
Despite the capricious nature of rabies vaccination laws, one thing is certain. Legally mandated canine rabies vaccines have dramatically reduced human exposure to the most lethal infectious disease on earth.
Hi, Anders here–I’m nudging Dr. B off of his soapbox for a few minutes to jump in on the Vet Blog today because I had the opportunity to meet with Dr. Barchas this past weekend for Tailer’s first check-up since he arrived from Sweden.
Due to Tailer’s leap of faith at 0:24 in the video, I almost posted this on Snuzzy as well, but in the end felt that, thanks to a super thorough and very informative interview with Dr. Barchas, it really needed to be posted here.
Dr. Barchas talks about common vaccines, rabies, feline Leukemia, feline HIV and microchipping, among other things. Hope you enjoy it–HUGE thanks to Dr. Barchas for making this happen.
You have questions. Veterinarian Eric Barchas (pronounced bark-us) has answers, plus stories from the vet’s office, commentary on pet news and more. This blog is brought to you by Dogster, Inc., makers of the hydrant-famous Dogster and the unnecessarily feared Catster. You can ask Dr. Barchas a question. If he can answer it he will.
This service is provided for educational purposes only. This blog is not a substitute for the regular veterinary care for your cats, dogs or other pets, that a licensed veterinarian provides through regular, routine office visits. Dogster.com is not an emergency consultation facility and does not provide advice or consultation regarding immediate emergency attention. If your pet has been in an accident, or is in immediate medical need, you need to contact your regular veterinarian or local animal hospital immediately.
Vaccines, as I have mentioned many times on this blog, are perennially controversial. Many people worry that pets are vaccinated too often. Experts voice concerns that over vaccination may lead to autoimmune disease. Leukemia and rabies vaccines in cats have been linked to cancers at the injection sites.
Rabies vaccination became a discussion in a dog park . . .
You have questions. 