Last week I gave a basic overview of vaccinations, including a discussion of why dogs need them. I made the distinction between core vaccines (those that every dog needs for public health reasons, including rabies, which is required by law) and noncore, which should be administered depending on a dog’s particular circumstances — exposure to other dogs, for example, or geographical location. The American Animal Hospital Association (AAHA)  recommends that noncore vaccines be given whenever the risk of the disease is high enough to override the risk of vaccination.

Here I pick up with a discussion of “the risk of vaccination” part of that equation.


Adverse Reactions

Very few dogs — less than ½ of 1% — have adverse reactions to vaccination. And most of those reactions are mild. But if your dog falls into a high-risk category (see the “Is Your Dog at Risk?” box) or you prefer to err on the side of caution, there are strategies that can help mitigate any potential problems.

[stextbox id=”alert” caption=”Is Your Dog at Risk?”]

A very large, comprehensive study — 1,226,159 dogs vaccinated with 3,439,576 doses of vaccine at 360 veterinary hospitals — conducted in 2005 determined that the dogs at greatest risk of having an adverse reaction to immunizations were young adult, small-breed, neutered dogs who received multiple vaccinations during a single office visit. (The results of this study can be found in JAVMA — Journal of the American Veterinary Medical Association — Vol. 227, No. 7, October 1, 2005; I would attach a pdf if I knew how.)

Most reactions fell into the following categories: swelling of the face and eye area (31%); raised, itchy areas (21%); generalized itching (15%); vomiting (10 %); swelling, inflammation, or soreness of the vaccination site (8 %); fever, lethargy, and lack of appetite (5.5%).  Most dogs were successfully treated with an antihistamine and/or glucocorticoid (steroid that reduces inflammation).

Small breeds. The larger the dog, the lower the risk of a reaction. Here’s why, and it’s a shocker: The manufacturers’ recommended dose for vaccines are not adjusted for body weight, in contrast to doses of almost all other veterinary pharmaceuticals.

Within the small breed category, the dogs most likely to experience symptoms after vaccination were dachshunds, pugs, Boston terriers, miniature pinschers and Chihuahuas. A genetic predisposition to allergies likely plays a role in this response because, in general, small mixed breeds had far fewer bad reactions to vaccination.

Multiple vaccinations:  The risk of a reaction increased as the number of vaccine doses administered per office visit increased, especially with small dogs. Each additional vaccine increased the likelihood of reaction by 27% in dogs that weighed less than 22 pounds and 12% in dogs larger than 22 pounds.

Neutered dogs: Both male (27%) and female (38%)  neutered dogs were more likely to have a reaction than sexually intact dogs.

Young adults: Dogs of approximately 1 to 3 years old had the greatest number of   adverse reactions, which is probably related to the fact that most boosters for puppy vaccinations are administered during this age span. Dogs older than 8 years experienced the fewest side effects.


There’s little you can do about most of the risk factors noted here — you can’t change your dog’s size or age or un-neuter him — but you can control how many vaccines you have your vet administer at a time. This requires spending additional money on individual office visits, but with an at risk dog it’s likely worth the investment in your peace of mind.

Another peace-of-mind inspiring tactic is to wait in the vet’s office for half an hour after the vaccination. Some 73% of reactions take place within the first 24 hours, and the most severe ones occur almost immediately.


Titers are blood tests that measure the level of immunity your dog has against various diseases by measuring the level of antibodies in the blood. Titering, also called vaccine serology, is becoming increasingly common.

Although effective in many cases, titering has several limitations, including expense. In addition to the cost of an office visit, you have to have your dog’s blood drawn and sent to be analyzed by a laboratory. Then, if your dog doesn’t show immunity, you have to return to the vet for a vaccination.

And titers are not available for all diseases. The most commonly administered and the most reliable are for the core diseases, parvovirus and distemper (there is also a titer for rabies, but no state allows its substitution for vaccination).  Nor are all titer tests as useful as others. Linda Ross, DVM, ACVIM at Cummings School of Veterinary Medicine at Tufts University, gives the example of leptosporosis, which has many strains. A titer test might find antibodies for one subtype of the disease, but your dog might still be susceptible to others. In addition, titers aren’t always a good gauge of the level of protection. Some dogs that don’t have a measurable number of antibodies nevertheless have immunity to the disease.

There is also the question of how often to titer. Dr. Ross asks the hypothetical questions: “If your dog has antibodies to a certain disease, when do you check again? The following year? Two years?” Still, Dr. Ross says, “If a client is concerned, especially the owner of a breed that’s susceptible to a reaction, having titers done is a good alternative to vaccination for those who can afford it.”

Talk to your Vet

Overall, the most important way to feel confident about your dog’s immunizations is to discuss them in detail with your veterinarian. It’s a two-way street. On the one hand, you should be comfortable asking about the potential side effects of any proposed vaccinations and how to recognize them. Inquire too about whether there are any restrictions for your dog in the days immediately following vaccination.

In turn, you should make your vet aware of any symptoms or medical issues your dog is experiencing; if your dog’s immune system is preoccupied with fighting off another disease, vaccination should usually be postponed. It’s also crucial to let your veterinarian know about any side effects your dog might have experienced in the past, even if you considered them too minimal or unrelated to report them at the time.

As Dr. Ross notes, you can expect your veterinarian to be very familiar with the ins and outs of vaccination because it’s a routine part of every practice. This is one instance where the generalist is a specialist.

28 thoughts on “Vaccinating Your Dog, Part 2: Risk Assessment”

  1. Buster just had his annual vet visit yesterday, and I’ve been watching him really closely – just in case! Fortunately, he only needed one booster and he seems to be fine. I know that only a very small percentage of dogs have a reaction, but Busty has so many sensitivities that I worry about him. We did talk about the Lyme vaccine with our vet yesterday, and he said it’s really good vaccine, but we opted for a flea/tick collar instead. Better to kill the little suckers (literally!) before they bite him. Hopefully we’ll keep him tick-free in New England this summer.

    1. I hear you, and I think being overcautious is better than the opposite. After all, if you weren’t watching and something went wrong, you’d be convinced that it was all your fault! Glad Buster seems to be doing fine. Being in areas where there’s Lyme disease is difficult — vaccines, chemicals in flea/tick collars… it’s a tough choice all around. But you can’t take any chances with that one and I hear the ticks are out in full force this year. Unless the recent cold snap helped get rid of them…

    1. Indeed! I was thinking of Lilly when looking at the data. She doesn’t seem to be high risk based on any of the categories either. I would wonder about whether it was a bad batch, except your vet would know if others had had similar reactions.

  2. We discuss vaccinations with the vet upon each annual visit. In our case that is twice per year since Sampson and Delilah are on protocol about six months apart. This is very good for our wallets. 🙂

    The discussion includes what the chances of them catching something. Currently we vaccinate for Rabies (state required every three years) and Leptos. When Delilah goes in June we will discuss Lyme and Parvo.

    I absolutely refuse to vaccinate for Bordatella. Both times Sampson got sick with the cough, he’d had the vaccine. Strangely enough the last time he had it, Delilah did not catch it even though she drinks from the same water dish.

    I’m a firm believer we over-vaccinate in this country. Don’t get me wrong if my vet said vaccinate for Bordatella I would, but the conversation usually ends with me asking, “What do you vaccinate your dog for?” If she vaccinates her dog then I usually follow suit.

    It’s a good thing to educate yourself (and your readers) about vaccinations. Just because someone in an authoratative position tells you “it’s ok” does not mean it is. Do your own research and be an advocate for your dog.

    Great information!!

    1. Thanks, Jodi. It sounds like you’re being very responsible and thoughtful about your dog care. What a drag about the Bordatella not being prevented by the vaccine. We don’t vaccinate humans nearly often; I wonder how we got in the habit of vaccinating our pets so frequently?

      1. Part of the super-vaccine process began in the 1970s when PARVO first hit and hit hard. Vets were scrambling to save these dogs, and when the vaccine came out, there was a real push to protect, protect, protect.

        Really before that, dogs mostly got rabies and distemper shots. The others came later.

  3. The one thing I’ve learned in my short time as a dog owner is how to be comfortable asking questions, no matter how silly they may seem or how many times I’ve asked them before. We actually switched vets last year when our previous clinic was most unhelpful and did not enjoy answering my questions – that and he didn’t seem to even like our dog. We are lucky in that our dog doesn’t seem to be sensitive to anything but it’s just smart to arm yourself with knowledge. And as I’ve learned, it never hurts to seek a second opinion.

    1. Ha! I know what you mean. Two vets in the practice I go to insulted Frankie. One said he was “weird”; another said he was a “bad patient”! Luckily, the third one is the kindest man in the universe and will answer my endless questions with endless patience. And he seems to like Frankie 😉

  4. Hi, Edie, great post! There’s a new titer test that only recently became available in the U.S. that pet parents should be aware of. It’s called VacciCheck (, which Spectrum Labs has made available to businesses such as vets, shelters and rescues. The test will check the antibody levels for canine parvovirus, distemper and infectious hepatitis-adenovirus type 2 viruses, to determine if a booster is REALLY required. The best part is results are provided within 21 minutes for a low cost. I hope this helps!

    1. Wow — great news on all counts. It sounds like VacciCheck resolves several of the problems described here, including the need to return to the vet for a second visit and also the high cost. I hope it gets into widespread use soon.

  5. Excellent series of posts, Edie. Although sometimes these issues mean that we have to make tough choices about whether to vaccinate, this info is extremely useful in helping people make an educated decision.

  6. My city actually accepts the rabies titer for licensing, and as far as I know, there is not currently a rabies law in my state. (Legislation is pending, though… and perhaps it’s passed?)

    However, if my dog were to bite someone, she would be treated as an unvaccinated dog and have to be quarantined.

    1. Interesting. I didn’t know that was possible, especially on a municipal — vs. state — level. What city do you live in, if you don’t mind saying?

  7. Very informative, I hope tittering becomes an option in the EU as well. Most country’s legislation require vaccination for rabbies. When we travel with the dogs they also regularly get their EU passports checked by customs (open internal borders, yeah right).

    I would wish the industry did something about the adjustment for body weight. That was a shocker indeed. Especially when you think small dogs are in the risk category – however small odds less than 1% percent might seem. I wonder why they have not already done that. Surely there must be a demand for it, like every other medicine.

    1. Interesting about the EU. I didn’t know there were no titering options – or that you get your passports checked at borders!

      It is odd about the dosage, isn’t it? I can understand why they don’t do long term tests for frequency of dosage — expense! — but adjusting for body weight seems like a no brainer.

  8. Hi Y”all,

    So glad to see so much discussion of vaccinations. Over the years I’ve researched vaccinations in horses, farm animals and of course our retrievers.

    Hawk is lucky to have 3 different vets he sees. One is an older rural vet, one a young vet who bought out the vet practice were we took him and the 3rd a large specialty hospital. The young vet was willing to forgo ALL vaccinations except Rabies last year. This year when a vaccination notice came Hawk was going for a check up at the specialist. The young vet he sees there discussed his clinics protocol on vaccinations. Once the puppy shots are out of the way…and no multi shots are given even to pups… they put the dogs on alternating 3 year regimen. If a dog has a problem or allergies they titer instead. Hawk had Rabies last year and the vet suggested Parvo this year.

    One comment mentioned Bordatello. I have refused the shot also. Lyme is another shot that is only good for one year. If you fail to vaccinate every year, evidently the protection is no longer good. I use tick prevention and watch Hawk closely. If I find a tick I check for signs of Lyme…an ounce of prevention…Years ago hubby and I both had Lyme that was not recognized and treated. The result was years of misery and health problems. Even though we’ve had Lyme we can get it again.

    Each of us owes it to ourselves and our pets to read everything we can on vaccinations and the deceases it protects against. This way we can make an intelligent decision that will hopefully benefit our own pet(s).

    BrownDog’s Human

    1. It’s so interesting to hear how much vaccination protocols have changed in your experience. Thank you very much for your contributions here to the conversation about vaccination.

  9. I’m so lucky to live in an area where rabies vaccination is not the law – and where we have a super low rabies rate despite that. I titer test my dogs and I have had fabulous experience finding groomers, boarders, sports classes and trainers that accept the titers. Felix exhibits a lot of the symptoms of rabies vaccinosis and we actually changed vets after learning that vaccinations were not even recommended for him (He has immuno-regulated allergies). I wish that more vets were interested in exploring the same information us pet owners are! Great post!

    1. Thanks, Jodi. I didn’t realize there were places where there was no law requiring rabies shots. That’s excellent that they accept titers. I do think that rabies vaccinations are essential because of the wild animals that can attack pets. I just read this awful story of someone whose dog was required to be destroyed because it had been near a rabid skunk and had never been vaccinated. Ugh.

  10. With a dog who had a mast cell reaction to a vaccine, I am very cautious to whatever goes into my dog now and always. When we know better we do better and all. TY for this and the outstanding research. This needs to be shared.

    1. Thanks, Carol. Glad you found it useful, even after the fact. Yes, some of that information was mind-boggling — especially the part about not adjusting vaccinations for the size of the dog.

  11. Leptospirosis is a zoonotic (potentially contagious to humans) disease that affects the kidneys and sometimes the liver. It is caused by the bacterium Leptospira interrogans. The core vaccine that contains distemper, adenovirus, parainfluenza and parvovirus is also available with the leptospirosis organism. However, this portion of the vaccine is the most reactive fraction of the combination core vaccine and is a common offender in causing adverse vaccination reactions in dogs. In addition, the immunity conferred by the leptospirosis portion is believed to be short-lived, probably six months or less. For these reasons, we do not recommend the leptospirosis vaccine be routinely administered to all dogs. If a doctor feels that a particular dog is at high risk, i.e., due to increased contact with potential wildlife reservoirs or with rats, he or she can offer the vaccine to the client. It is not to be used in puppies less than 16 weeks of age.

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