Vaccine Adverse Reactions

1. VACCINATION OF SMALL BREED DOGS: Is it appropriate to reduce the volume of an individual dose of parenteral vaccine when vaccinating small breed dogs?

The volume recommended by the manufacturer generally represents the minimum immunizing dose; therefore, the total volume of a vaccine dose should always be administered. Arbitrarily reducing the volume of a vaccine may result in an immune response that is less than protective. Furthermore, there is no evidence that lowering the dose/volume of a vaccine will prevent an adverse event.

Administration of reduced dose volume of a rabies vaccine is “off-label” and may not be supported in state or local law.

2. INAPPROPRIATE ADMINISTRATION OF VACCINE: What are the consequences of administering an IN or oral Bordetella bronchiseptica vaccine by the SQ or IM route?

IN and oral Bordetella bronchiseptica vaccines contain live, avirulent gram-negative bacteria capable of replication following administration. For this reason, these vaccines must be administered by the route for which the product is licensed. B. bronchiseptica vaccine that is licensed for parenteral administration is inactivated, is incapable of replication post-administration, and therefore must be administered by injection.

Intranasal B. bronchiseptica vaccine administered parenterally (subcutaneously) has been reported (rarely) to cause cellulitis and abscess formation at the injection site. Deaths associated with bacterial replication, bacteremia, release of hepatotoxic proteins, and hepatic necrosis have been reported.72,100,101, 103

Dogs inadvertently vaccinated with an oral or intranasal Bordetella bronchiseptica vaccine administered parenterally may benefit from a minimum 5-day treatment with an appropriate antibiotic (e.g., doxycycline).

NOTE: Administration of an oral or intranasal Bordetella bronchiseptica vaccine to a patient that is concurrently receiving antibiotic therapy may significantly alter the vaccine (live bacteria) resulting in minimal or no response following vaccination.

3. ANTIMICROBIAL THERAPY and VACCINATION. Should an oral or intranasal vaccine containing Bordetella bronchiseptica be administered to a dog that is concurrently receiving antibiotic therapy?

Doing so is not recommended. Because B. bronchiseptica vaccines administered onto a mucosal surface (oral and intranasal) contain living (attenuated) bacteria, vaccination of a dog that is concurrently receiving antimicrobial therapy may culminate in the inactivation of the live bacteria. This could result in a reduced or no immune response to the vaccine.

4. FAILURE TO IMMUNIZE: Will administration of vaccine to a puppy “bind” or otherwise deplete Maternally Derived Antibody (MDA), leaving the dog susceptible to infection?

Vaccination in the presence of MDA can interfere with the vaccine but will not deplete, or measurably alter, the level of protection a puppy derives from passive (maternal) immunity.

5. FAILURE TO IMMUNIZE. Are nosodes (holistic preparations) effective agents in preventing infectious disease in a dog?

Nosodes have never been demonstrated (even in challenge studies) to provide a measurable degree of prevention against a vaccine preventable disease in dogs. They do not immunize because they do not contain sufficient amounts of antigen required for the development of cell-mediated and/or humoral immunity.9

6. FAILURE TO IMMUNIZE. Are there new variants of canine distemper viruses (CDV) in the field for which current CDV vaccines do not provide protective immunity?

All of the current infectious CDV (modified-live virus and recombinant) vaccines provide protection against all the known isolates (variants) of CDV.26

7. FAILURE TO IMMUNIZE. Do the current infectious canine parvovirus (CPV) vaccines provide protection from disease caused by the CPV-2c variant present in North America?

Currently, all attenuated CPV vaccines induce a protective immune response that provides long-term (>3 yr) protection from all known CPV variants (2a, 2b, and 2c) once the initial vaccination series has been administered.

NOTE: CPV vaccines provide excellent immunity among the majority of vaccinates. However, other “host” factors such as MDA, genetic non-responder status, concurrent illness or CPV infection, etc. may lead to failure of a vaccine dose to immunize.28,29

8. FAILURE TO IMMUNIZE. Are certain breeds incapable of mounting an immune response following vaccination?

Although rare, “genetic non-responders” have been documented among dogs in several countries (best characterized in the United States during the 1980s among Doberman Pinschers and Rottweilers that failed to develop protective canine parvovirus antibody following administration of an appropriate series of core vaccines).

Canine parvovirus vaccine “non-responders” do exist within the general canine population today. It is suggested that as many as 1 in 1000 dogs (predominantly purebred) are genetically incapable of responding to the parvovirus antigen and, therefore, remain susceptible to the consequences of infection if exposed.

Anecdotally, reports of young, well-vaccinated Pit Bull terriers developing fulminant parvovirus infection, despite an excellent vaccination history, have surfaced throughout the United States.

No vaccine is considered 100% effective among 100% of vaccinates. Therefore, it is likely that undocumented failure to respond does occur following vaccination against diseases other than canine parvovirus infection.

9. ACUTE REACTIONS. Should dogs with a history of acute post-vaccinal adverse reaction (angioedema, anaphylaxis, etc.) receive booster vaccines?

The decision to revaccinate a dog in which an acute, post-vaccination adverse reaction occurred must be based on assessment of the patient’s current health status, vaccination history, immune status (antibody testing), risk for exposure, as well as the number of vaccines deemed necessary at the time of the appointment.

Dogs with a history of a mild, acute post-vaccination reaction (e.g., facial swelling) are commonly treated with a single dose of diphenhydramine prior to vaccination (although the benefit of doing so has not been definitively established); dogs that have a mild post-vaccination reaction that requires treatment should receive a single, anti-inflammatory dose of a corticosteroid.

Dogs with a history of having had a serious, acute vaccine-associated reaction (anaphylaxis) should not be revaccinated unless deemed necessary and then only when the patient can be monitored for several hours post-vaccination.

NOTE: While a small number of states authorize veterinarians to exempt the rabies virus vaccination requirement on medical grounds, most states mandate that dogs be revaccinated against rabies virus regardless of the dog’s health status or medical history (see

10. ACUTE REACTIONS. Does the acute adverse reaction risk of a killed (inactivated) vaccine persist in the individual patient for an extended period or is it of short duration?

The duration of immune memory associated with acute (type 1) hypersensitivity is difficult to predict. Among children that experience relatively minor post-vaccination acute type 1 hypersensitivity reactions (e.g., angioedema), the risk of an adverse reaction tends to decrease with age. It is not known if this consistently occurs in dogs.

Dogs experiencing a severe, type 1 hypersensitivity reaction (e.g., systemic anaphylaxis) must be monitored closely following subsequent vaccine administration or, as an option, tested for the presence of antibody (canine distemper virus, parvovirus and adenovirus-2) to assess the need to administer a vaccine.

11. DELAYED REACTIONS. Should dogs with a history of a suspected delayed-onset post-vaccinal adverse reaction (e.g., immune-mediated hemolytic anemia or thrombocytopenia) receive booster vaccines?

Doing so is not generally recommended. When feasible, avoid administering booster doses of vaccine to patients having a history of immune-mediated disease (e.g., hemolytic anemia, thrombocytopenia). It has been suggested that doing so could re-activate disease. Testing for antibody (canine distemper virus, parvovirus and adenovirus-2) is a means of assessing protective immune status in at-risk dogs.

NOTE: While a small number of states authorize veterinarians to exempt the rabies virus vaccination requirement on medical grounds, most states mandate that dogs be revaccinated against rabies virus regardless of the dog’s age, health status, or medical history (for information on your state see

12. DELAYED REACTIONS. Can vaccines cause immune-mediated disease?

Immunologically speaking, it is possible. While vaccination has been anecdotally linked to immune-mediated disease in dogs, definitive studies demonstrating a clear cause-and-effect relationship have not been published.

Immune-mediated disease following vaccination has been documented in humans (e.g., Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy [CIDP]).

In veterinary medicine, the relationship between vaccine-associated immune-mediated disease and vaccination has been associated with (although not definitively proven) adjuvant in inactivated (killed) vaccine.14,87,89,97 It has also been suggested that in dogs/cats vaccine administration may pose a risk for re-activation of an immune-mediated disease from which the patient recovered. In these dogs, and when feasible, it may be prudent to forego administration of booster vaccines and perform antibody testing instead.